The Raw Vegan Diet - Worth A Try?

Raw food diets are a big hit right now - Instagram is swamped with thousands of pictures of raw meals, and more raw food products keep popping up in our supermarkets and health food shops. Advocates of raw food diets, including celebrities like Gwyneth Paltrow, Sting, and Demi Moore, claim the health benefits range from weight loss to detoxifying our bodies. Many supporters of the diet also claim that raw food is 'alive' and cooked food is 'dead', because cooking food supposedly destroys nutrients and enzymes. 

On the other hand, most health care professionals dismiss raw food diets as a fad that puts dieters at risk of developing eating disorders, nutritional deficiencies, and of being stigmatized.

As ever, I want to take a balanced look at both sides of the argument using the best evidence we have, to answer some of the common questions about raw food diets:

What is a raw food diet?

The diet consists of uncooked, unprocessed foods – mainly raw fruits, vegetables, nuts, and seeds.

It’s possible to warm your food a bit – but not above 40C (104F). Some like to sprout grains and beans to make them edible without cooking them. Fermenting foods and the use of dehydrators are also allowed to provide a little more variety into your diet. 

Does cooking food destroy nutrients?

Yes and no. Certain nutrients, such as vitamin C and folate, are decreased during cooking, especially when vegetables are boiled rather than steamed or baked (1).

However, other nutrients, such as the carotenoids beta-carotene, lycopene, and lutein, are made much more bioavailable (your body can absorb more of it) when cooked (2). Carotenoids are really important because they've been shown to be associated with decreased risk of cancers, cardiovascular diseases, and obesity (3). Another example is curcumin, the yellow pigment found in turmeric that has antioxidant and anti-inflammatory effects shown to protect against many diseases, including cancers, cardiovascular disease, and even arthritis (4-6). Eaten raw, the health effects are limited because of its extremely limited water solubility. However, when cooked, there can be up to a 12-fold increase in the solubility and therefore the amount we can absorb and benefit from (7). One more example is oxalates, found in some plants, which inhibit the absorption of calcium, iron and zinc. Cooking vegetables significantly reduces oxalate levels (8), so when many plant foods are cooked, absorption of calcium, iron and zinc is actually improved.

There’s loads more examples of how cooking food can decrease levels of some nutrients, but increase the bioavailability of others. So while a raw food diet may help you take in higher levels of certain nutrients, sticking solely to raw foods can actually put you at risk of becoming deficient in several others.

Is a raw food diet nutritionally complete?

Raw food diets naturally encourage the consumption of more fruit and veg, and that’s always a good idea. Fruit and veg are rich in vitamins, minerals, fibre, phytonutrients and antioxidants, and a higher intake of them is associated with reduced risk of cardiovascular disease, cancer, and all-cause mortality (9).

However, while it is possible to eat beans and grains ‘raw’, the process involves soaking and sprouting, which can take days. While sprouted foods can be a great addition to the diet (see my guide to sprouting here), the effort involved means most raw foodies won’t eat them regularly enough. And since whole grains, beans, chickpeas, and lentils are significant sources of protein, iron, and zinc - especially important for vegans - it’s easy to become deficient in many of these essential nutrients on a raw food diet.

And this has been shown in human studies: people on raw food diets have shown to have low plasma lycopene (10), and low intakes of vitamin D, zinc, and calcium (11). In fact, almost a third of women surveyed on a raw food diet had partial or complete amenorrhea (missed periods) possibly due to the lack of certain nutrients and calories in the diet (12).

What about the enzymes?

It’s undeniably true – cooking food denatures enzymes found in plants, which is why raw foodies don’t heat their food over 40C.

But hang on a minute… memories of GCSE biology are kicking in here... doesn’t acid also denature enzymes? The hydrochloric acid released by the parietal cells in our stomachs is strong enough to kill bacteria, convert pepsinogen into pepsin to break down proteins, and it’s certainly strong enough to denature almost all plant enzymes. A few do make it through to the small intestine, for example fermented foods like sauerkraut can carry enzymes through to the gut. But the effect is minimal – digestion in the gut relies almost entirely on human-generated bile and pancreatic enzymes.

So it really seems that labelling raw food ‘alive’ and cooked food as ‘dead’ is a classic marketing tactic, designed to play to people’s emotions and to help sell diets / products.

Does a raw food diet help you lose weight?

Most of the evidence around the weight loss effects of raw food diets is anecdotal, not conducted under controlled conditions, and so should be taken with a pinch of salt (more on what evidence to believe here). That being said, it does make sense that you’d lose weight on the diet, seeing as processed foods like cakes, sweets, cookies, doughnuts, pastries, cheese, processed meats (you get the point, lots of the unhealthy foods) are shunned.

But hold on a minute – in order to cut out these junk foods, do you need to be on a raw food diet? Absolutely not. If weight loss is your goal, why not do it in a healthy way that doesn’t put you at risk of deficiencies and still benefits from all the wonderful foods that are usually cooked? For example, whole grains can help with weight loss and have a long list of other health benefits (as I explained here). Beans and pulses, which aren’t typically eaten often on a raw food diet, can also be really helpful with weight loss because they’re so high in protein and fibre, both of which help to increase satiety. Higher protein diets can help preserve muscle during weight loss (13), which improves metabolism and makes the weight loss more sustainable.

So yes, a raw vegan diet can help with weight loss, but it doesn’t seem to be the most sustainable (or enjoyable!) way to do it.

Can a raw vegan diet help with detoxing?

Hmmm, detoxing… I promised balanced arguments, but when it comes to detox diets, there really isn’t any science at all to back them up, so this point has to be a little one-sided!

What does detoxing mean to you? Flushing our system of an accumulation of toxins that builds up in our bodies over time, leaving our organs squeaky clean and healthy?

Well, firstly, isn’t that what our liver, kidneys, gut, skin, and even lungs are for? Your body is unimaginably expert at getting rid of toxins already, and it does so through thousands of complex chemical reactions to create substances that can then be excreted. In fact there’s no known way to make this incredibly complex system, which already works amazingly well, work any better.

Secondly, what toxins exactly are removed by raw food diets, or any ‘detox’ diet for that matter? If these toxins were named, then we could measure them before and after the ‘detoxes’ to test their effectiveness. They’re never actually named, because detoxes are untested, bogus treatments, that belong firmly in the realm of pseudoscience.

As you can probably tell, I feel quite strongly against detox diets. Unfortunately, the word ‘detox’ has been hijacked by entrepreneurs to sell products, treatments, and programmes in exchange for large sums of money. They also encourage people to believe that they can live unhealthily because they can always just ‘detox’ later on to reverse any damage they’ve done. So overall, people end up less healthy, and so do their bank accounts.

Are there any other drawbacks of raw vegan diets?

There’s no doubt about it: a raw vegan diet is restrictive. There are rarely raw food options at restaurants, so one of life’s greatest pleasures – dining out with family and friends – can be at best awkward, or at worst impossible. Friends may also find it difficult to cater for you at dinner parties and so it can even become socially isolating.

And just imagine all of those amazing cuisines / foods that are off the menu on a raw food diet: freshly baked bread, hearty winter stews, barbecued vegetables, rich pasta dishes, curry… imagine a life without curry!

Having a healthy relationship with food is one of the most important ways we can stay healthy and happy. Allowing yourself to believe that some foods can be ‘dead vs. alive’ or even ‘dirty vs. clean’ creates unhealthy eating habits and can even lead to eating disorders like orthorexia, an obsession with eating healthily that paradoxically often becomes dangerously unhealthy for both the mind and the body.

On a practical level, there’s a high level of effort involved with raw food diets too – if you want any kind of variety in your diet, you’ll need to use food dehydrators, and be constantly fermenting foods or soaking / sprouting grains and pulses. It has also been linked to dental problems – the high intake of acidic and sugary fruit, plus the tendency to ‘graze’ throughout the day on raw snacks and juices, leads to tooth decay as plaque acids form on your teeth and damage the enamel.

So what’s the take-home message?

There are some positive aspects of raw food diets: it cuts out processed junk foods and, as with pretty much any type of diet, it at least gets people conscious about what they eat (so many people just eat unconsciously, which in itself can be a dangerous habit).

However, a raw food diet can leave you at risk of deficiencies and can have many other social and psychological drawbacks. While it can help you to lose weight, there are other healthier, more enjoyable, and more sustainable ways to do it. And it certainly doesn't 'detox' your body. An important drawback for me, and for anyone else who enjoys great food, is that you miss out on so many wonderful and healthy cuisines - a travesty in my opinion! 

My advice? Eat lots of fruit and vegetables, that's the most important thing. And just eat them how you like them. A varied, balanced, diet containing lots of raw and cooked vegetables (along with whole grains, beans, pulses, nuts, and seeds) is the best solution - and most importantly remember... enjoy your food! 

References:

1. Chai, W., & Liebman, M. (2005). Effect of different cooking methods on vegetable oxalate content. Journal Of Agricultural And Food Chemistry, 53(8), 3027-3030.

2. Livny, O., Reifen, R., Levy, I., Madar, Z., Faulks, R., Southon, S., & Schwartz, B. (2003). β-carotene bioavailability from differently processed carrot meals in human ileostomy volunteers. European Journal of Nutrition, 42(6), 338-345.

3. Perveen, R., Suleria, H., Anjum, F., Butt, M., Pasha, I., & Ahmad, S. (2013). Tomato (Solanum lycopersicum) carotenoids & lycopenes chemistry; Metabolism, absorption, nutrition and allied health claims- A comprehensive review. Critical Reviews in Food Science and Nutrition, Critical Reviews in Food Science and Nutrition, 01 January 2013.

4. Teiten, M., Gaascht, F., Eifes, S., Dicato, M., & Diederich, M. (2010). Chemopreventive potential of curcumin in prostate cancer. Genes & Nutrition, 5(1), 61-74.

5. Wongcharoen, & Phrommintikul. (2009). The protective role of curcumin in cardiovascular diseases. International Journal of Cardiology, 133(2), 145-151.

6. Daily, J., Yang, M., & Park, S. (2016). Efficacy of Turmeric Extracts and Curcumin for Alleviating the Symptoms of Joint Arthritis: A Systematic Review and Meta-Analysis of Randomized Clinical Trials. Journal of Medicinal Food, 19(8), 717-729.

7. Kurien, B., Singh, A., Matsumoto, H., & Scofield, R. (2007). Improving the solubility and pharmacological efficacy of curcumin by heat treatment. Assay and Drug Development Technologies, 5(4), 567-76.

8. Chai, W., & Liebman, M. (2005). Effect of different cooking methods on vegetable oxalate content. Journal of Agricultural and Food Chemistry, 53(8), 3027-30.

9. Aune, D., Giovannucci, E., Boffetta, P., Fadnes, L., Keum, N., Norat, T., . . . Tonstad, S. (2017). Fruit and vegetable intake and the risk of cardiovascular disease, total cancer and all-cause mortality—a systematic review and dose-response meta-analysis of prospective studies. International Journal of Epidemiology, 46(3), 1029-1056.

10. Garcia, A., Koebnick, C., Dagnelie, P., Strassner, C., Elmadfa, I., Katz, N., . . . Hoffmann, I. (2008). Long-term strict raw food diet is associated with favourable plasma beta-carotene and low plasma lycopene concentrations in Germans. The British Journal of Nutrition, 99(6), 1293-300.

11. Strassner, C., Doerries, S., Kwanbunian, K., & Leitzmann, C. (1999). Vegetarian raw food diet: Health habits and nutrient intake. American Journal Of Clinical Nutrition, 70(3), 632S.

12. Koebnick, Strassner, Hoffmann, & Leitzmann. (1999). Consequences of a Long-Term Raw Food Diet on Body Weight and Menstruation: Results of a Questionnaire Survey. Annals of Nutrition & Metabolism, 43(2), 69-79.

13. Soenen, S., Martens, E., Hochstenbach-Waelen, A., Lemmens, S., & Westerterp-Plantenga, M. (2013). Normal protein intake is required for body weight loss and weight maintenance, and elevated protein intake for additional preservation of resting energy expenditure and fat free mass. The Journal of Nutrition, 143(5), 591-6.

Gluten - Friend or Foe?

For some, gluten can cause serious problems: diarrhoea, abdominal pain, indigestion, fatigue, deficiencies, and even nerve damage are some of the complications caused by eating gluten for people with coeliac disease. With the condition, eating gluten (a protein found in wheat, barley, and rye) causes the immune system to produce antibodies that attack the lining of the small intestine. Some people also suffer with wheat allergies, where an immune response to any of the proteins found in wheat (not just gluten) can cause vomiting, diarrhoea, hives, and difficulty breathing.

Quite rightly, it’s also more recently been recognised and accepted that non-coeliac or wheat allergy patients can suffer too, in the form of gluten sensitivity. Here, eating even small amounts can cause uncomfortable bloating, headaches, and chronic fatigue. For people who suffer from these conditions, the increase in the availability of gluten-free products is a real blessing as it makes dealing with strict gluten-free diets much easier.

But, seeing as these three conditions affect about 2% of the population (coeliac disease affects 1 in 100, wheat allergy approx. 1 in 1000, and gluten sensitivity around 1 in 100), why have sales of gluten-free products soared so high in recent years? 22% of the UK has bought or eaten a gluten-free product at least once in the last six months (1).

Most people buy gluten-free products because they believe they’re healthier, rather than for medical reasons. This could be down to celebrity endorsements from the likes of Miley Cyrus and Kim Kardashian who claim there are health benefits or even weight loss properties of gluten free diets.

It could also be because of the huge increase in clever marketing creating a ‘health halo’ effect (even the packaging of these products makes them look healthier). It’s understandable why investment in marketing campaigns is so extensive, as the industry was worth an estimated $5 billion globally last year and is set to continue growing. Producers and retailers are capitalising on this growth in demand: while many staple food products have been facing price deflation, gluten-free products increased in price by 23% on average between 2011 and 2016.

But Can Gluten Be Healthy?

For healthcare professionals, this growth in popularity of gluten-free diets is seriously perplexing. Because for the approximately 98% of the population who do not have gluten issues, whole grains (including wheat, barley, and rye) have some important and significant health-promoting effects. They’re rich in phytochemicals, antioxidants, vitamins, trace minerals, dietary fibre, and protein. In fact, because they’re so nutritious, increasing the amount in your diet has been shown to be associated with:

·       Lowered blood pressure and reduced risk of cardiovascular disease (2)

·       Reduced risk of some cancers (3,4)

·       Reduced risk of diabetes (5)

·       Lower body weight (6)

In fact, a gluten-free diet among healthy adults has been shown to negatively effect beneficial gut bacteria populations and immune function, because some of the components found in whole grains act as prebiotics, which feed our good gut bacteria (7). All of these reasons are why, as part of a balanced diet, experts suggest eating three portions of whole grains a day (8).

You may have heard stories about people without gluten issues feeling much better going gluten-free. This may well be the case, but if cutting out gluten means they’ve also shunned cakes, biscuits, doughnuts, pizza, pastries, and beer, then there’s no wonder they felt healthier. Cutting out gluten can also make it easier not to overeat. Think about it: pizza, pasta, and bread are some of the easiest foods to over-eat with, which can in itself cause bloating. Of course, if you feel unwell after eating just one slice of bread on an empty stomach, then it’s worth getting checked out (but you should see a doctor before you go gluten-free, because it’s more difficult to establish if someone has gluten issues after they’ve cut it out for a while).

The take home message? For the 98% of the population without gluten issues, save your money by avoiding expensive gluten-free products, and instead spend that money on higher quality foods - treat yourself to some fresh, locally made bread from the bakers (which won’t contain all the artificial softeners and preservatives that commercial bread contains). And try to aim for whole grains because the bran and the germ, which are removed in white cereals, are where you find most of the fibre and nutrients. But even white bread and pasta are significant sources of nutrients in the UK, as by law, white wheat flour is fortified with iron, calcium, thiamine and niacin. Aim for three portions of whole grains a day: it’s great for your health and – just as importantly – it means you get to enjoy some incredibly tasty foods. This ultimately is the key, because when you stop restricting yourself unnecessarily, you can build a really positive relationship with food, and you’re more likely to keep your healthy habits long into the future!

References

1. http://www.mintel.com/press-centre/food-and-drink/free-from-gains-momentum-sales-of-free-from-food-products-forecast-to-surpass-half-a-billion-in-the-uk-in-2016

2. Tighe, Paula, Duthie, Garry, Vaughan, Nicholas, Brittenden, Julie, Simpson, William G, Duthie, Susan, . . . Thies, Frank. (2010). Effect of increased consumption of whole-grain foods on blood pressure and other cardiovascular risk markers in healthy middle-aged persons: A randomized controlled trial. The American Journal of Clinical Nutrition, 92(4), 733-40.

3. Aune, D., Chan, D., Lau, R., Vieira, R., Greenwood, D., Kampman, E., & Norat, T. (2011). Dietary fibre, whole grains, and risk of colorectal cancer: Systematic review and dose-response meta-analysis of prospective studies. BMJ : British Medical Journal, 343, BMJ : British Medical Journal, 2011, Vol.343.

4. Skeie, G., Braaten, T., Olsen, A., Kyrø, C., Tjønneland, A., Landberg, R., . . . Lund, E. (2016). Intake of whole grains and incidence of oesophageal cancer in the HELGA Cohort. European Journal of Epidemiology, 31(4), 405-414.

5. Chanson-Rolle, A., Meynier, A., Aubin, F., Lappi, J., Poutanen, K., Vinoy, S., . . . Barengo, N. (2015). Systematic Review and Meta-Analysis of Human Studies to Support a Quantitative Recommendation for Whole Grain Intake in Relation to Type 2 Diabetes (Meta-Analysis to Recommend a Whole Grain Intake). 10(6), E0131377.

6. Giacco, Della Pepa, Luongo, & Riccardi. (2011). Whole grain intake in relation to body weight: From epidemiological evidence to clinical trials. Nutrition, Metabolism and Cardiovascular Diseases, 21(12), 901-908.

7. De Palma, G., Nadal, I., Collado, M., & Sanz, Y. (2009). Effects of a gluten-free diet on gut microbiota and immune function in healthy adult human subjects. British Journal of Nutrition, 102(8), 1154-1160.

8. https://www.bda.uk.com/foodfacts/wholegrains.pdf

Coconut oil – the pros, the cons, and the 'as-yet unknowns'

Not many food products in history have boomed in popularity like coconut oil has in recent years, with a 500% increase in global demand for the product over the last decade.

But not many food products in history also come with such conflicting messages about their effects on health.

Even as a nutritionist, until I looked a little deeper into the research, I didn’t really know what to make of all the information out there.

What I did notice was that information touting the health benefits of coconut oil seem to mostly focus on the topical uses (such as applying to hair or skin) as well as the health benefits of medium-chain triglycerides (a type of saturated fat that makes up over half of the fats in the oil).

And while there are good quality studies behind some of the health benefits of coconut oil, other information comes from more questionable sources like celebrity endorsements, food producers / retailers with a financial interest, and low quality studies (e.g. done on mice).

Comparatively, the quality of the evidence warning us of the detrimental health effects seems to be much more robust (see my article on which types of evidence to believe here).

Here’s a breakdown of the most significant pros and cons of coconut oil, along with any issues with the credibility of the evidence:

Coconut oil: health benefits

Coconut oil is very high in saturated fat, and while most sources of saturated fat are made up of a high proportion of long-chain triglycerides, more than half of the saturated fats in coconut oil are medium chain triglycerides (MCTs). It's these MCT's that are behind most of the health claims behind coconut oil:

• MCTs can be easily converted to ketones by the liver, providing an alternative energy source for the brain which can be beneficial in the treatment of Alzheimer’s disease (1). However, there is no evidence that coconut oil can prevent Alzheimer’s from developing in the first place.

• MCTs do have some antibiotic properties – they can disrupt the cell membranes of bacteria and inhibit the growth of some pathogens (2). However, this has only ever been shown in vitro (i.e. in test tubes, petri dishes etc). There are no studies to show that eating coconut oil can prevent diseases in the human body.

• Some studies suggest that MCTs can aid in weight loss (3,4) compared to other fats. However, the evidence is not the highest quality (most studies have been done on mice, or very low numbers of humans).

• Coconut oil can be used topically to treat dermatitis (5) and there’s some anecdotal reports that it can prevent dandruff, possibly due to the lauric acid content, which has antimicrobial and antifungal properties.

Coconut oil: the health risks

• While coconut oil has been shown in some studies to aid in weight loss, these changes are very minor and the reports encourage many people to add too much of it to their diets. All fats contain 9 calories per gram, and coconut oil is no exception. Therefore, if you are adding extra coconut oil on top of what you’d normally eat, you’re likely to gain weight, not lose weight. There are many MUCH more effective, healthier, and cheaper ways to help with weight loss!

• A systematic review (one of the best forms of evidence) evaluated 21 human studies of coconut oil and concluded that it raised total cholesterol and LDL cholesterol (the bad type) more than unsaturated plant oils such as olive oil (6). They concluded that replacing coconut oil with unsaturated plant oils alters blood lipid profiles and reduces risk factors for cardiovascular disease.

• The environment should be taken into consideration too - of course coconuts do not tend to grow in the West so transporting them from top producing countries like Indonesia and The Philippines requires burning through more fossil fuels than if we used home-grown oils like rapeseed. Coconuts also tend to be grown as a mono-crop, meaning large areas of land with low biodiversity which can effect the environment. Lastly, large proportions of small-scale coconut farmers live in poverty, averaging about $1 per day throughout the year.

What should we make of all this?!

To summarise, there is some (slightly weaker) evidence behind the health benefits of coconut oil, and some (slightly stronger) evidence behind the negative effects. But there are still a lot of 'as-yet-unknowns' too. Any article you read that shows a very strong opinion either way is probably biased somehow, as none of the scientific evidence is overwhelmingly strong. 

While I'll enjoy watching out for any higher quality future studies, I for one plan to continue using coconut oil occasionally. It does help to enhance the flavours of certain dishes like curries, and also because it's solid at room temperature it can improve the consistency of homemade sweet treats like these vegan brownies. As I mentioned in a previous post about fats, we certainly shouldn't avoid fats altogether. But I will limit how much I use - as with any oil it contains about 120 calories per tablespoon, and the evidence behind the effects on LDL cholesterol is pretty strong. 

Regarding the sustainability of coconut oil, buying Fair Trade goes a long way, because as well as helping the environment by improving water conservation and proper waste disposal, it also helps to ensure safe working conditions and fairer pay for coconut farmers. 

So, if like me, you plan to continue using coconut oil but perhaps a little more sparsely, you can afford to go for a higher quality Fair Trade variety. 

References

1. Newport, Vanitallie, Kashiwaya, King, & Veech. (2015). A new way to produce hyperketonemia: Use of ketone ester in a case of Alzheimer's disease. Alzheimer's & Dementia: The Journal of the Alzheimer's Association, 11(1), 99-103.

2. Shilling, M., Matt, L., Rubin, E., Visitacion, M., Haller, N., Grey, S., & Woolverton, C. (2013). Antimicrobial effects of virgin coconut oil and its medium-chain fatty acids on Clostridium difficile. Journal of Medicinal Food, 16(12), 1079-85.

3. Lei, T., Xie, W., Han, J., Corkey, B., Hamilton, J., & Guo, W. (2004). Medium-chain Fatty acids attenuate agonist-stimulated lipolysis, mimicking the effects of starvation. Obesity Research, 12(4), 599-611.

4. Liau, K., Lee, Y., Chen, C., & Rasool, A. (2011). An Open-Label Pilot Study to Assess the Efficacy and Safety of Virgin Coconut Oil in Reducing Visceral Adiposity. ISRN Pharmacology, 2011, 7.

5. Verallo-Rowell, V., Dillague, K., & Syah-Tjundawan, B. (2008). Novel antibacterial and emollient effects of coconut and virgin olive oils in adult atopic dermatitis. Dermatitis : Contact, Atopic, Occupational, Drug,19(6), 308-15.

6. Eyres, Laurence, Eyres, Michael F., Chisholm, Alexandra, & Brown, Rachel C. (2016). Coconut oil consumption and cardiovascular risk factors in humans. Nutrition Reviews, 74(4), 267-280.

Should We Avoid Fats?

If we don’t want to get fat, we shouldn’t eat fat, right?

Well, the answer is not as simple as that. Yes, gram for gram, fat is the most calorific of the major food groups, containing 9 calories per gram (compared to 4 calories per gram of protein or carbohydrates). For this reason, it's suggested to limit fat intake to 70g per day (95g per day for men), because too much of any kind of fat can contribute to weight gain.

But does this mean we should be avoiding fat altogether? Most certainly not. Here are the reasons why:

Weight control

It sounds kind of counter-intuitive, but for weight loss or control, you should not be avoiding fats. Here’s why:

• Fats make you feel fuller. Fats take a long time to digest, and when fat hits your intestines, hormones that increase satiety, such as CCK and PYY, are released. In fact, studies have shown that meals rich in omega-3 fatty acids increase the feeling of fullness both directly after, and two hours after, eating the meal (2).
• Low fat foods are often high in sugars. When low (or zero) fat foods are made, in order to make them taste good, manufacturers tend to pump them full of sugar. Sugars raise blood sugar levels, triggering the release of insulin to bring them back down. How does insulin bring sugar levels down? Often by storing them as fat.
• Dietary fat can boost fat metabolism. Diets rich in healthy fats increase the release of the hormone adiponectin from your fat cells (3). Adiponectin plays important roles regulating insulin sensitivity, glucose and fat metabolism, which is why low levels of the hormone are associated with obesity. 

This sounds amazing – we no longer have to fear fats! While this is definitely true, it does come with two important caveats:

1. Not all fatty foods are created equal - the types of fats we eat are really important. We should aim to eat mono- and polyunsaturated fats, found in leafy vegetables, avocado, nuts, seeds, olive oil, and rapeseed oil. And we should limit saturated and trans fats, found in fatty meats, cheese, lard, cakes, biscuits, pies, and many processed or fried foods, as these can harm our health. 
2. Fat intake should still be within the UK guidelines. All fats, saturated or not, contain 9 calories per gram. So do add healthy fats to your diet, just not with reckless abandon, as the calories can mount up if you’re not careful.

Absorption of vitamins

Dietary fats are important for the absorption of fat-soluble vitamins (A, D, K and E). Without an adequate amount of fat in our diets, our bodies are unable to effectively absorb and process these vitamins, which are essential for our health.

Essential fatty acids

We can synthesise most fatty acids in our body. However, the ones we can’t make, and therefore must get from our diet, are the polyunsaturated fats linoleic acid (omega-6) and alpha-linoleic acid (omega-3). Omega-3 and 6 are essential for the normal functioning of all tissues in the body – so cutting out fats altogether can affect a whole host of symptoms and disorders. 

References:

1. https://www.nutrition.org.uk/nutritionscience/nutrients-food-and-ingredients/fat.html?limit=1&start=4

2.  Parra, Ramel, Bandarra, Kiely, Martínez, & Thorsdottir. (2008). A diet rich in long chain omega-3 fatty acids modulates satiety in overweight and obese volunteers during weight loss. Appetite,51(3), 676-680.

3.  Von Frankenberg, A., Silva, F., De Almeida, J., Piccoli, V., Do Nascimento, F., Sost, M., . . . Gerchman, F. (2014). Effect of dietary lipids on circulating adiponectin: A systematic review with meta-analysis of randomised controlled trials. The British Journal of Nutrition, 112(8), 1235-50.

The Truth About Soy

I get asked a lot whether or not soybeans and soy products, such as tofu and tempeh, are good for you. And it’s easy to see why there’s so much confusion on this topic, as many of the headline messages we see in the media are very conflicting. Some hail tofu as some kind of super-food, while after reading others you might expect to grow a third eye. So, I thought I would bring you the best quality and most up-to-date scientific evidence on the health topics surrounding soy.

Soy and hormones in men

The top concern I hear about from men is whether soy can affect male hormone levels. There have in the past been concerns about oestrogen-like activities of the isoflavones found in soy decreasing testosterone levels in men. However, the basis of these claims stems from early studies in rodents. And it’s been shown that rodents metabolise isoflavones very differently to humans. In fact, a recent meta-analysis – one of the best form of scientific evidence – combined the results from 15 human clinical trials, and concluded that soy foods do not alter testosterone levels in men (ref). Even at higher than average rates of consumption (higher than is even typical among some Asian cultures), there is also no evidence that soy isoflavones affect circulating oestrogen levels in men (ref). This does all kind of make sense… the hundreds of millions of men in Asian cultures who frequently eat soy products are not infertile or growing ‘man boobs’. In fact, there is reason to believe that soy is one of the reasons why the Japanese, among the biggest soy eating countries in the world, is also one of the healthiest nations. This brings me on to the health benefits of soy:

Soy is an excellent source of protein

Soybeans are a complete protein, meaning they provide all the essential amino acids (the ones we have to get from our food because we can’t make them in our body). A cup of cooked soy beans contains a whopping 22g protein, a 150g serving of tempeh has 28g, and a 150g serving of tofu contains 19g. This means for anyone looking to increase their protein intake, which can help with short-term weight loss or gaining muscle and strength, soy products can be an extremely useful addition to the diet.

Soy can replace foods that are bad for you

As mentioned, soy provides an excellent source of protein, and all without the cholesterol and saturated fat levels found in most meat products. So if you swap a pork sausage hot dog for a soy-based alternative, you are avoiding processed meat, which is bad for our health in a number of ways. If you’re replacing it with a high protein, low fat, high vitamin and mineral based food like tofu, there are significant advantages for your health.

Soy could be protective against cancer

This has been a topic of debate in the past, again because of early studies in rats who metabolise phyto-oestrogens differently to humans. But recent meta-analyses, which combine the results of numerous clinical trials in humans, show that soy consumption could in fact be associated with reduced risk of breast cancer incidence (ref) and prostate cancer (ref). These effects have been shown to be both through direct mehanims, and through the ‘displacement’ of red and processed meats (as mentioned above). That’s equally as important because red and processed meats have been classified by the World Health Organisation as carcinogens (cancer causing) (ref).

Soy can decrease risk of heart disease and stroke

Soy products can reduce our risk of heart disease and stroke, because they reduce our blood cholesterol levels (ref). It does this in two ways: firstly, by directly reducing our liver’s cholesterol output. Secondly, again through the ‘displacement’ theory - soy products like tofu are often eaten as a replacement in our meals for meat products, which are much higher in saturated fat. By replacing meat with tofu or tempeh, the saturated fat content of the meal is significantly reduced, which is why soy consumption is associated with lower risk of heart disease and stroke (ref).

Soy can improve bone health

Increased consumption of soy foods is associated with improved markers of bone health and lower risk of osteoporosis and bone fractures, especially in post-menopausal women (ref). More research is needed here but the evidence so far is very promising! (ref)

The downsides of soy products

Soy products that have been processed to resemble the taste of a bacon rasher or turkey slice require quite a bit of processing, and the ingredients list can look worryingly long. There is often added salt and fat in anything that has been battered, and other flavourings and colourings in mock-meat style products to give it a ‘meaty’ flavour. As with any foods, generally the less processing the better. For this reason, simple tofu is much better than the heavily processed imitation meats. Better still, tempeh which is made by simply fermenting cooked soybeans, is even less processed than tofu, and contains more protein too.

The take home message

The reason some people worry about soy foods is mainly because of early studies conducted in rats that used especially high levels of phyto-oestrogens. As mentioned before, rats metabolise the phyto-oestrogens in soy very differently to humans, and there’s a large (and growing) body of evidence showing the significant health benefits of soy products in humans. Want to incorporate soy into your diet more? Try my crispy sesame-coated baked tofu, incredible tofu quiche, or make a tofu ‘bacon’ BLT.

Should We Drink Coffee?

It seems that every few weeks there’s an article in the health sections of the papers about coffee or caffeine. Some of them seem to hail coffee as some kind of 'superfood', while others warn us of the dangers of drinking too much of the stuff. As with many nutritional messages reported by the media, the hype around coffee is pretty confusing and conflicting. But while we're drinking around 70 million cups of coffee every day in the UK, it’s worth knowing if we should be drinking it at all. Well, here’s a breakdown of the best scientific evidence behind that aromatic beverage so many of us love:

The Health Benefits of Drinking Coffee

As well as caffeine, coffee is loaded with potent compounds such as chlorogenic acid and polyphenols, which have antioxidant properties and contribute significantly towards antioxidant intake in Western diets (1). The combination of these compounds could delay the absorption of blood sugar, increase metabolic rate, and help blood vessels contract and relax. These actions may account for why coffee drinking is associated with lower risk of: 

• Obesity (2)

• Stroke (3)

• Developing type 2 diabetes (4)

• Neurological diseases such as Alzheimer’s (5) and Parkinson’s disease (6)

• Coffee has also been shown in meta-analyses (large reviews combining the results of numerous trials) to be significantly protective against several cancers, including colorectal (7), liver (8), oral (9), and pancreatic (10).

From a fitness perspective, the caffeine in coffee acts as a stimulant by blocking the inhibitory neurotransmitter adenosine (11) which can reduce fatigue, making you: Firstly, less likely to skip training sessions because you're feeling tired / sluggish; and secondly, improve alertness and concentration during training, meaning once you're at the gym, you're more likely to push yourself harder and make bigger improvements (12).

The Risks of Drinking Coffee

In some people, too much caffeine can lead to insomnia, nervousness, heart palpitations, and 'the jitters'. Caffeine taken in after lunchtime is particularly likely to interfere with sleep, and getting less sleep puts you at risk for other chronic conditions in the long term.

As mentioned, coffee reduces risk of several cancers. For most other cancers, it has no significant effect, with the exception of lung cancer, where risk is increased, but only amongst smokers (13). There is also some evidence that coffee could increase risk of non-fatal myocardial infarction (heart attack) amongst those with the gene that means caffeine is metabolised slowly (about half of us) (14, 15).

The polyphenols in coffee can inhibit absorption of non-heme iron (the kind found in plants) in a meal by between 50 and 90% (16). So vegetarians and vegans need to be particularly careful about holding back on the coffee for at least 30 minutes before or after eating to ensure iron absorption is maximised.

It’s also worth noting that all of the benefits mentioned above are referring to black coffee. The biggest risk of all comes from what you may add to it – creams, sugar, or sugary syrups add saturated fat and empty calories to your brew, raising blood sugar and promoting weight gain. It’s also important to brew coffee with filter paper, as unfiltered coffee (such as Turkish brew or French press) contains cafestol, a substance that can increase LDL (bad) cholesterol levels (17).

From an environmental perspective, it must be said that coffee isn’t great for the planet. Deforestation to make way for sun-cultivated coffee has seen off 2.5 million acres of natural ecosystems in Central America alone so far. There are also issues with water contamination, chemical use, waste, and soil quality / erosion. And take away coffees have the added impact of the used cups (7 million a day in the UK alone) that go to landfill, as most paper coffee cups are fused with polyethylene to make them waterproof and can’t be recycled. Coffee pods have also come under fire recently, with the vast majority of the 500 million pods sold just in the UK in 2015 ending up in landfill, where they will take 500+ years to break down. If this is an important issue to you, check out my five easy steps to reduce the amount of plastic you use.

Take-home messages

The protective effects of drinking coffee against many diseases may explain why there is good evidence that overall, drinking coffee could help you live longer (18). However, some people should limit coffee consumption, especially pregnant women, smokers, those with anxiety issues, high blood pressure, or insomnia.

If you already drink coffee, try following these guidelines to maximise the benefits:

• Stick to no more than five cups a day to keep your caffeine intake at a safe level

• Try to drink coffee in the mornings only, to avoid disrupting your sleep

• Limit the amount of unfiltered coffee you drink

• Leave 30 minutes either side of eating to reduce the inhibition of iron absorption

• Stick to black coffee without sugar, or use low fat nut / soy milk if you prefer

• Reduce your coffee intake if you would like to lower your environmental impact, or at least stick to making your own coffee instead of using takeaway cups or coffee pods

Lastly - if coffee isn’t already part of your daily rituals, don’t worry about starting a love affair with the stuff; it's not for everyone and there are plenty of other ways to stay healthy without forcing yourself to drink it. 

References:

1. Svilaas, Arne, Sakhi, Amrit, & Svilaas, Tone. (2004). Intakes of Antioxidants in Coffee, Wine, and Vegetables Are Correlated with Plasma Carotenoids in Humans1. The Journal of Nutrition, 134(3), 562-7.

2. Nordestgaard, Ask Tybjærg, Thomsen, Mette, & Nordestgaard, Børge Grønne. (2015). Coffee intake and risk of obesity, metabolic syndrome and type 2 diabetes: A Mendelian randomization study. International Journal of Epidemiology, 44(2), 551-565.

3. Zhang, R., Wang, Y., Song, B., Jørgensen, H., & Xu, S. (2012). Coffee consumption and risk of stroke: A meta-analysis of cohort studies. Central European Journal of Medicine, 7(3), 310-316.

4. Jiang, Xiubo, Zhang, Dongfeng, & Jiang, Wenjie. (2014). Coffee and caffeine intake and incidence of type 2 diabetes mellitus: A meta-analysis of prospective studies. European Journal of Nutrition, 53(1), 25-38.

5. Liu, Qing-Ping, Wu, Yan-Feng, Cheng, Hong-Yu, Xia, Tao, Ding, Hong, Wang, Hui, . . . Xu, Yun. (2016). Habitual coffee consumption and risk of cognitive decline/dementia: A systematic review and meta-analysis of prospective cohort studies. Nutrition, 32(6), 628-636.

6. Qi, H., & Li, S. (2014). Dose–response meta‐analysis on coffee, tea and caffeine consumption with risk of Parkinson's disease. Geriatrics & Gerontology International, 14(2), 430-439.

7. Li, G., Ma, D., Zhang, Y., Zheng, W., & Wang, P. (2013). Coffee consumption and risk of colorectal cancer: A meta-analysis of observational studies. 16(2), 346-357.

8. Yu, C., Cao, Q., Chen, P., Yang, S., Deng, M., Wang, Y., & Li, L. (2016). An updated dose-response meta-analysis of coffee consumption and liver cancer risk. Scientific Reports, 6, 37488.

9. Li, Ya-Min, Peng, Juan, & Li, Le-Zhi. (2016). Coffee consumption associated with reduced risk of oral cancer: A meta-analysis. Oral Surgery, Oral Medicine, Oral Pathology and Oral Radiology, 121(4), 381-389.e1.

10. Jie Dong, Jian Zou, Xiao-Feng Yu. (2011). Coffee drinking and pancreatic cancer risk: A meta-analysis of cohort studies. World Journal of Gastroenterology, 17(9), 1204-1210.

11. Fredholm, B. (1995). Adenosine, Adenosine Receptors and the Actions of Caffeine *. Pharmacology & Toxicology, 76(2), 93-101. 

12. Doherty, M., & Smith, P. (2004). Effects of caffeine ingestion on exercise testing: A meta-analysis. International Journal of Sport Nutrition and Exercise Metabolism, 14(6), 626-46.

13. Anqiang Wang, Shanshan Wang, Chengpei Zhu, Hanchun Huang, Liangcai Wu, Xueshuai Wan, Haitao Zhao. (2016). Coffee and cancer risk: A meta-analysis of prospective observational studies. Scientific Reports, 6, Scientific Reports, 2016, Vol.6.

14. Cornelis, M., El-Sohemy, A., Kabagambe, E., & Campos, H. (2006). Coffee, CYP1A2 genotype, and risk of myocardial infarction. JAMA, 295(10), 1135-41.

15. Nawrot, Perez, Künzli, Munters, & Nemery. (2011). Public health importance of triggers of myocardial infarction: A comparative risk assessment. The Lancet, 377(9767), 732-740.

16. Hurrell, R., Reddy, M., & Cook, J. (1999). Inhibition of non-haem iron absorption in man by polyphenolic-containing beverages. British Journal of Nutrition, 81(4), 289-295.

17. Hingston, C., & Wise, M. (2015). Coffee brewing technique as a confounder in observational studies. Heart, 101(20), 1686.

18. Freedman, N., Park, Y., Abnet, C., Hollenbeck, A., & Sinha, R. (2012). Association of Coffee Drinking with Total and Cause-Specific Mortality. The New England Journal of Medicine, 366(20), 1891-1904.

How to eat to maximise your training

Whether you are trying to lose weight, put on muscle, or simply get fitter - how you eat is just as important as the training you do. If you've made a good start with your fitness plan, but are struggling to take your training to the next level, you may find that when you eat, as well as what you eat, could play a big part in pushing the boundaries. This is for two main reasons:

•    What and when you eat plays a huge part in how you feel when you exercise and therefore can influence how hard you push yourself. You should be pushing yourself to the limits every training session, and you're not going to make much progress if you go to the gym feeling sluggish and end up plodding along on the treadmill, hardly breaking a sweat. 

•    What you eat before and after exercise can affect muscle recovery and therefore to maximise on your hard work, getting the right fuel at the right times can lead to faster progress. 

So, here are four tips to make your eating habits work for you to maximise the results from your training:

1. Eat a healthy breakfast

This rule applies whatever your goals may be. Most of the energy you got from your dinner the previous night will be used up by the morning, meaning your muscle glycogen (stored carbohydrates that power your training), will likely be low. And whether trying to gain muscle or lose weight, you're not going to get much out of your morning gym session if you're feeling tired or lightheaded when you exercise. So make sure to eat to give your body the energy it needs to get a really productive session in. 

Despite many people claiming that eating breakfast 'kickstarts' your metabolism, there is no clear evidence of this. But there are definitely benefits: it has been shown that people who eat breakfast tend to expend more energy during the day (1). And especially if you have a high fibre breakfast, you are likely to feel fuller for longer, reducing the likelihood of making poor food choices later in the day (2). So even if you don’t work out in the morning, getting a healthy breakfast in will set you up for the day and lead to healthier habits. The best quick breakfasts for providing complex carbohydrates needed to fuel your sessions, along with protein for muscle recovery and fibre to keep you full, include:

·      A smoothie, made with at least 50% vegetables, mixed with fruit, water, plus a vegan protein powder

·      Wholegrain toast with peanut butter or homemade chia seed jam

·      Porridge made with almond milk, topped with a nut butter and sliced fruit

2. Size of your meals

On the other side of things, if you eat too much before a workout, you may feel slowed down and sluggish. As a general guideline:

•    Large meals - leave at least 3 hours before exercising

•    Small meals - leave at least 2 hours before exercising

•    Snacks - eat these 30-60 minutes before exercising 

3. Eating after you exercise

Muscle protein breakdown occurs during exercise. But don’t worry, it's the process you have to go through to promote muscle protein synthesis (muscle growth), which increases for up to 48 hours after working out. Because muscle protein synthesis peaks immediately after exercise, then reduces over time, intake of dietary protein soon after exercise is important to maximise muscle growth. However, this 'window of opportunity' is not as small as many gym-goers believe, so you do not need to instantly rush to neck a protein shake within five minutes of your workout – up to 30 minutes is fine. This is especially true if you follow tip number one, as the protein you consume in the hours before your workout will by now be absorbed and available in the bloodstream to aid muscle recovery and growth. In fact, spreading your protein intake more evenly during the day after training is more effective at promoting muscle growth than fewer, larger intakes of protein (3).

An equally important factor is making sure to consume carbohydrates after you exercise, because this inhibits the muscle protein breakdown that occurs during, and for a while after, your training. Eating carbohydrates, especially simple sugary carbohydrates, quickly increase blood sugar levels, and this triggers the release of insulin to try and bring blood sugar levels back down. Usually, you would want to avoid insulin spikes, but after exercise, increased insulin helps to drive nutrients, including amino acids, into the muscle cells, preventing muscle protein breakdown (4). So a small glass of fruit juice, some natural sweets or dextrose tablets, or a tablespoon of jam / syrup along with your protein source will aid muscle recovery, without promoting fat gain. Eating carbohydrates on the days you train also ensures that you replenish your muscle glycogen so you are ready to perform your best on your next session. 

So, in short, make sure to consume protein (10-20g) and simple carbohydrates (15-40g, depending on the intensity of your workout, your weight, your goals, etc) soon after your workouts, even if you are following a low carbohydrate diet. And make sure to spread your protein intake evenly throughout the day, not just immediately after training, as muscle protein synthesis will continue for up to 48 hours after you’ve finished.

4.     Stay hydrated

You need to drink enough fluids to avoid becoming dehydrated before, during, and after your workouts. The American College of Sports Medicine recommends to:

·      Drink about 2-3 cups of water during the 2-3 hours before your workout.

·      Drink about 1-2 cups of water every 30-40 minutes during your workout. This can be adjusted according to your workout intensity and the weather.

·      Drink about 2-3 cups of water for every pound of weight you lose during the exercise.

Most importantly - learn from your experiences!

Everyone is different when it comes to eating around exercise, and will depend on your fitness levels, your goals, your weight, and personal preferences. Notice how your body feels during workouts in response to your eating patterns and how your diet affects the progress you make, so you can adapt to what works best for you to achieve your fitness goals sooner.

1.     Wyatt, H., Grunwald, G., Mosca, C., Klem, M., Wing, R., & Hill, J. (2002). Long-term weight loss and breakfast in subjects in the National Weight Control Registry. Obesity Research, 10(2), 78-82.

2.     Turconi G, Bazzano R, Caramella R, Porrini M, Crovetti R, Lanzola E (1995). The effects of high intakes of fibre ingested at breakfast on satiety. Eur J Clin Nutr. 49: 281-285.

3.     Areta, J., Burke, L., Ross, M., Camera, D., West, D., Broad, E., Coffey, V. (2013). Timing and distribution of protein ingestion during prolonged recovery from resistance exercise alters myofibrillar protein synthesis. Journal of Physiology, 591(9), 2319-2331.

4.     Biolo, & Wolfe. (1993). Insulin action on protein metabolism. Bailliere's Clinical Endocrinology and Metabolism, 7(4), 989-1005.

Everything You Need To Know About Vitamin B12

Vitamin B12

Vitamin B12 (also referred to as cobalamin) is a really important nutrient for vegetarians, and especially vegans, to be aware of. This is because it is the only vitamin that cannot be found in plants. The UK government recommend an intake of 1.5μg (micrograms) per day for both male and female adults (British Nutrition Foundation, 2015).

Vitamin B12 is water soluble and 60% of B12 in the body is stored in the liver. These stores can last up to several years, and so after becoming vegan, it may be a year or two (or more) before initial signs of deficiency show, including fatigue and anaemia. Because it's an important vitamin for blood cell formation and the nervous system, further depletion can then lead to more severe features such as bone marrow suppression, abnormal reflexes, and memory loss.

So how can we make sure we're getting enough vitamin B12 in our diets? Well, vegetarians get some B12 from dairy and eggs, and many vegan foods are fortified with B12 - including breakfast cereals, spreads, nut milks, and some nutritional yeasts. The amounts vary from country to country and from brand to brand, so read the labels carefully.

Supplements are recommended for vegans who do not eat 2-3 fortified foods a day. B12, both in supplements and fortified foods, is simply sourced from culturing bacteria, which make B12 as a by-product. This is the same way that animals make B12 - the only difference is for them, the bacteria making it live inside their guts. So vegans get their B12 from the very same source as every other animal on the planet – micro-organisms! Getting your B12 from fortified foods or supplements doesn't cause suffering to animals, or cause environmental damage, so that's a win on every level. 

Here is the amount of B12 recommended intake by The Vegan Society (2001):

• Eat fortified foods 2-3 times a day to provide 3μg per day
• OR take a daily B12 supplement providing  at least 10μg
• OR take a weekly B12 supplement providing at least 2000μg

The reason they suggest the higher doses for the daily and weekly supplements is because B12 is absorbed better in small doses. So, the less frequently you obtain B12, the more you need to take.

Plant-based tip! Many meat eaters like to use B12 to criticise plant-based diets by saying that if vegans rely on a supplement, then their diet cannot be 'natural'. In fact, I find the opposite to be true, and I find being well informed and prepared very useful for when a debate on the topic might arise. So, here are my thoughts on why I am more than happy to take B12: 

• There is also nothing 'natural' about factory farming (where 90% of meat comes from)
• Evolution is natural, and humans have evolved to use their intelligence to enable a cruelty-free and sustainable diet. Why not take advantage of this?
• Most people (over half the US adult population) take supplements, so why only call vegan diets ‘unnatural’? 

I'd love to hear about any other stances you take when people try to criticise veganism on the grounds of requiring a supplement - leave your comments below!