Fit for life diet

Fit for Life (FFL) is a diet and lifestyle stemming from the principles of Natural Hygiene. It is promoted mainly by the American writers Harvey and Marilyn Diamond.[1] As the title of the 1985 book suggests, Fit for Life claims that one can lose excess body weight and maintain good health via long term dietary and lifestyle practices, rather than short term dieting. In the Fit for Life book series many dietary principles are recommended including eating only fruit in the morning, eating predominantly "live...high-water-content" food, and if eating animal protein to avoid combining it with complex carbohydrates.

While the diet has been praised for encouraging the consumption of raw fruits and vegetables, several other aspects of the diet have been disputed by dietitians and nutritionists,[1] and the American Dietetic Association and the American Academy of Family Physicians list it as a fad diet.

The diet is based on Diamond's exploration of Herbert M. Shelton theories of food combining. Both authors claimed to be able to bring about weight loss without the need to count calories or undertake anything more than a reasonable exercise program. In the first version of the program, Diamond claimed that if one eats the foods in the wrong combination they "cause fermentation" in the stomach. This in turns gives rise to the destruction of valuable enzymes & nutrients. Diamond categorized foods into two groups : "dead foods" that "clog" the body, and "living foods" that "cleanse" it. According to Fit for Life principles, dead foods are those that have highly refined or highly processed origins; while living foods are raw fruits and vegetables. The basic points of Fit for Life are as follows:[1]

  • Fruits are best eaten fresh & raw. Where possible they should be eaten alone.
  • Carbohydrates & Proteins should never be combined in the one meal.
  • Water dilutes stomach digestive juices & should never be drunk at meals.
  • Dairy foods are considered of limited value & due to their allergic capacity, should seldom, if ever, be eaten.

In the 2000s, the Fit for Life system added the Personalized FFL Weight Management Program, which employs proprietary protocols called Biochemical "Analyzation", Metabolic Typing and Genetic Predispositions. The Diamonds claim that these protocols allow the personalization of the diet, which thus customized is effective only for one individual, and can be used for that person's entire life. This version of the diet also puts less emphasis on "live" and "dead" foods, and instead talks of "enzyme deficient foods." The Diamonds posit that enzymes that digest proteins interfere with enzymes that digest carbohydrates, justifying some of the rules above. They also began to sell nutritional supplements, advertised as enzyme supplements, many of which are strongly recommended in the newest version of FFL.[1]

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