The raw food diet dates back at least to the mid-1800s when a US Presbyterian minister claimed people would never become ill if they only ate uncooked foods. But over the last few decades it has resurfaced. So is there any truth in this?
Although there has been a lot of academic research on raw food diets, almost all of it relates to cat and dog food. There are only a few academic papers on human studies, often using different designs and measures, so there is only a patchy evidence database.
- In general, most proponents of raw food diets are also vegetarian or vegan, and they often eat very low levels of starchy carbohydrates (bread, rice or pasta).
- 1999 study found almost all raw food eaters had a much higher rate of erosion of tooth enamel, thought to be due to high fruit consumption. Their levels of plant derived antioxidants were either only at normal level, or sometimes at low level, attributed to very low fat consumption, which traditionally acts as a delivery mechanism for such oil-based antioxidants.
- 2005 study found those with largely raw food diets had lower cholesterol and triglyceride levels; not surprising as participants were eating an average of 20 servings of fruit and veg. However, participants were often deficient in vitamin B12, found almost exclusively in animal products in nature.
- Another 2005 study found similar mixed results. Raw food eaters tended to weigh less and be leaner than the general population, but had significantly lower bone density in clinically important skeletal regions.
There are good, underlying reasons why animal foods are best eaten cooked.
- Cooking renders animal foods safe from potentially life-threatening parasites and microbes.
- Humans don't produce the right digestive enzymes or harbour the necessary gut flora to access calories in uncooked carbohydrates.
- For some plant foods (e.g. tomatoes), cooking allows improved access to nutrients by breaking down the cell walls. With kale and spinach, cooking reduces the volume and removes difficult to digest compounds, so we can eat a larger amount of them.
Evolutionary anthropologists suggest it was the advent of cooking that triggered the reduction in gut size that allowed us to develop larger brains. Cooking food is not only an ideal way of getting a varied, balanced diet, but is probably what made us human.
Source: Are there benefits to a raw food diet? by James Wong, New Scientist, 2 Jan. 2021
