Raw veganism seems about the most restrictive diet out there, but those who follow it preach its endless benefits and claim cooked food is not merely less beneficial, but actually “toxic” to our bodies. From enzymes and micronutrients to curing cancer, it’s interesting to see just how many of these claims stand up to science.
Claim #1: Cooking destroys nutrients
Sounds a bit vague, hmm? It depends which nutrients we’re talking about. Cooking vegetables does reduce the vitamin C content (1), as vitamin C is unstable, heat-sensitive, and dissolves in water. But on the other hand, lycopene (an antioxidant that makes veggies red) is much more bioavailable (available for your body to use) when cooked (2). This is at least in part due to the fact that cooking breaks down the cellulose fibres in the food, which we can’t digest, so the nutrients attached become more accessible. The same goes for beta-carotene in vegetables like carrots.
A molecule in many plant but not animal foods is oxalate, which inhibits calcium and iron absorption from foods. So, for example, spinach may be a good source of both of these, yet the presence of oxalates (and phytates) in spinach reduces the bioavailability of these nutrients, and your body doesn’t use them. However, this mainly applies to raw spinach, as cooking decreases oxalates and therefore increases absorption of iron and calcium from these foods (3).
Obviously it goes without saying that excessively cooking foods to a complete mush, or charring them, isn’t going to give you any benefits as water-soluble vitamins can easily end up in the cooking water instead. But eating all your veggies raw isn’t the best solution either.
Claim #2: Raw food contains “live” enzymes
Yep, can’t argue with this one. Cooking food destroys plant enzymes, which is why raw foodies tend to set a limit of 40°C. But you know what else destroys plant enzymes? Your digestive system, duh. Your stomach sits at a comfortable pH of around 2-3 thanks to the production of gastric acids. That’s highly acidic, as enzymes such as proteases which break down proteins function optimally in this kind of environment. If you cast your mind back to high school chemistry, you’ll remember that enzymes are easily denatured by both heat and pH (here’s a reminder that’s GCSE-friendly).
Essentially, plant enzymes are not going to help you with digestion. Enzymes in some fermented foods such as sauerkraut will actually make it past the stomach intact, but they still contribute negligibly towards our digestion process.
Come on guys, this is GCSE chemistry here, you’re just making this too easy for me!
Calling raw foods “alive” and cooked foods “dead” is just another example of appealing to people’s morals and emotional side rather than objective facts to sell a diet. It’s total BS. If enzymes were an indicator of life then a test tube of pure enzymes would also be considered “alive”, and I’m pretty sure we can all agree that’s not the basis for determining life.
Claim #3: a raw food diet is a great way to detoxify your body
This only needs one sentence: YOU HAVE A LIVER AND KIDNEYS. They are there to eliminate toxins. Wonderful. There’s no evidence to suggest a raw food diet or a juice fast or whatever other BS people come up with next is going to help you detox. I’ve written more about this here.
Claim #4: a raw food diet can cure diabetes/cancer/regrow your amputated leg
Ok that last one isn’t real. Bu I hope you can appreciate my frustration by this point. A raw food diet isn’t a cure for anything. That doesn’t mean diet isn’t an important factor in both preventing and treating lifestyle diseases such as type-2 diabetes – weight loss is universally acknowledged as playing a crucial role. And yes, high consumption of fruits and vegetables does reduce the risk of developing certain cancers, but that doesn’t make it a cure.
Raw food and juicing treatments for cancer (like Gerson Therapy) have been found to be ineffective by both the National Cancer Institute and the American Cancer Society (4). The reason I specifically want to highlight Gerson is because it featured in the media last year as the treatment Jess Ainscough chose over conventional cancer treatment, and which ultimately led to her death.
A raw vegan diet can lead to deficiencies in protein, vitamin D, vitamin B12, zinc, and calcium (5). These have potentially dangerous long-term effects. A raw vegan diet has no proven health benefits over a vegan or vegetarian diet, but with the pitfalls of restriction, challenging social situations, and potential deficiencies.
Eat your vegetables how you like them. The important thing is that you eat them, and worrying about minor details like the bioavailability of nutrients isn’t really worth your time. A diet featuring both raw and cooked vegetables offers the best solution, and my guess is that’s what you were probably doing all along anyway.
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