The impression we get is that there’s rather high occurrence of gut cancer, including stomach, duodenum, colon … [
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I want to talk about why I think that is, since the danger that the Optimal Dieters are discovering was one of the key factors leading us to formulate and publish the Perfect Health Diet.
Zero-Carb Diets Can Induce Mucus Deficiency
I ate a high-vegetable but extremely low-carb diet from December 2005 to January 2008. At the time I thought I was getting about 300 carb calories a day, but I now consider this to have been a zero-carb diet, since I don’t believe carb calories are available from most vegetables. Vegetable carbs are mostly consumed by gut bacteria, whose assistance we need to break down vegetable matter, or by intestinal cells which consume glucose during digestion.
Throughout my 2 years on this zero-carb diet, I had dry eyes and dry mouth. My eyes were bloodshot and irritated, and I had to give up wearing contact lenses. Through repeated experiments, I established that two factors contributed to the dry eyes – vitamin C deficiency and glucose deficiency. After I solved the vitamin C issue, I did perhaps 50 experiments over the following few years, increasing carbs which made the dry eyes go away and reducing them which made them immediately come back. This established unequivocally that it was a glucose deficiency alone that caused the dry eyes.
Conclusion
A healthy diet should be robust to faults. The Optimal Diet is not robust to glucose deficiency.
There’s good reason to suspect that at least some of the Optimal Dieters developed mucin deficiencies as a result of the body’s effort to conserve glucose and protein. This would have substantially elevated risk of gastrointestinal cancers. Thus, it’s not a great surprise that many Optimal Dieters have been coming down with GI cancers after 15-20 years on the diet.
We recommend a carb plus protein intake of at least 600 calories per day to avoid possible glucose deficiency. It’s plausible that a zero-carb diet that included at least 600 calories per day protein for gluconeogenesis would not elevate gastrointestinal cancer risks as much as the Optimal Diet. But why be the guinea pig who tests this idea? Your body needs some glucose, and it’s surely less stressful on the body to supply some glucose, rather than forcing the body to manufacture glucose from protein.
Fasting and low-carb ketogenic diets are therapeutic for various conditions. But anyone on a fast or ketogenic diet should carefully monitor eyes and mouth for signs of decreased saliva or tear production. If there is a sign of dry eyes or dry mouth, the fast should be interrupted to eat some glucose/starch. Rice is a good source. The concern is not only cancer in 15 years; a healthy mucosal barrier is also essential to protect the gut and airways against pathogens.
