Some vegans decide to choose a raw-food diet. What are the health benefits of this lifestyle compared to a vegan diet that includes cooked foods?
The question is indeed very broad, but it can receive an answer. I think that one should always consider benefits and side-effects/risks, so I will include some information about both.
- (claim) enzymes preservation - according to this source,
The idea behind this diet is that heating breaks down useful enzymes in a food. These enzymes are an important part of the digestive process, helping to break down food so that the optimal amount of nutrients is released. Raw foodists believe that cooked foods take longer for our bodies to digest and can cause clogged arteries and sluggish digestive systems.
However, a reference cited by Wikipedia states that "enzymes in food are digested and play no role in human biology."
(claim) higher nutrient and antioxidants values - the same Wikipedia section indicates that "cooking degrades nutrients or increases their availability, or both, depends on the food and how it is cooked."
helps weight loss - raw diet is usually a low calorie one and might result in significant weight loss.
decreased cancer risk for certain types of cancer (source)
Consumption of raw vegetables tended to be associated with decreased cancer risks somewhat more often than consumption of cooked vegetables.
- favorable serum LDL cholesterol and triglycerides as indicated by this study
Of the participants, 14% had high serum LDL cholesterol concentrations, 46% had low serum HDL cholesterol, and none had high triglycerides.
The same referenced sources indicate the downsides of adopting raw-foodism
- the time and effort
You will also have to stay away from processed and pre-made food, leaving you responsible for preparing everything that goes in your mouth.
- possible toxicity
There are many foods that can be toxic when consumed raw. These include buckwheat, kidney beans, eggs and parsnips. You may also find yourself suffering from irritable bowel syndrome and other digestive problems when starting out.
- high risk of development impairment of children and infants
there may not be enough vitamin B12, enough vitamin D, and enough calories for a growing child on a totally raw vegan diet.
- elevated plasma Hhomocysteine (B12 deficiency is involved) and low serum HDL cholesterol
This study concludes about the serologic changes:
In conclusion, the present study indicates that a strict raw food diet may result in remarkably low serum total cholesterol and triglyceride concentrations. However, the elevated tHcy as well as the low HDL cholesterol concentrations in participants in this study could provide a mechanistic explanation of the higher mortality from coronary heart disease in vegans compared with ovo-lacto-vegetarians, which was reported in a recent meta-analysis of prospective studies.
The process of cooking food results in a decrease in total nutrient content. In many cases, cooking increases the bioavailability of nutrients, both by making the foods easier to digest and making foods taste better so that you eat more of them. These effects vary for each nutrient, and cooking method.
A few examples
Vegetables and calcium
Boiling vegetables will greatly reduce their calcium content because calcium dissolves in water. However, that calcium hasn't been destroyed, it still exists in the water. Using the water as a soup broth means you now have a calcium rich soup. You can also preserve the calcium content by using a different cooking method. Frying or steaming your vegetables will not result in as much calcium loss as boiling.
Beans and fiber
Cooking beans will break down the fiber they contain. There is less total fiber in cooked beans than in raw beans. However, the weakened broken down fiber is far easier to digest. Additionally, raw beans are not a particularly enjoyable food, and you won't get any nutrients from something you won't eat!