Ultra-restrictive diets fail in the long term not due to a lack of willpower, but because an overly significant caloric deficit forces the body to activate biological survival mechanisms (stress, increased hunger, storage) that inevitably lead to weight regain.

noli's read

The notion that very restrictive diets fail in the long term due to physiological survival mechanisms is well-supported scientifically. A major meta-analysis led by Anderson et al. (American Journal of Clinical Nutrition) shows that after 5 years, more than 80% of the weight lost during structured programs is regained, which validates the concept of the yo-yo effect. Furthermore, a literature review conducted by the University of California, Los Angeles (Mann et al.) confirms that strict caloric restriction triggers natural biological defenses against food scarcity. These reactions increase appetite while slowing the rate at which the body uses energy to function on a daily basis. The figure of "85% failure" mentioned by the creator is therefore consistent with research data, which generally estimate the long-term weight regain rate to be between 80% and 95%. Finally, the analogy to sleep deprivation is sound, as a lack of rest also disrupts energy balance and accentuates hunger signals.

the sources

No named source held this one up — that absence is part of the verdict.