Hunger is the most powerful adaptation during a diet, surpassing even metabolic slowing, because the body biologically prioritizes the search for food as soon as energy reserves decrease.

noli's read

Layne Norton highlights a well-documented biological mechanism here: during an energy deficit, the body increases hunger signals (via ghrelin) and decreases satiety (via leptin) to drive caloric intake. Meta-analyses on metabolic adaptation (e.g., Trexler et al., Journal of the International Society of Sports Nutrition) confirm that while metabolism does indeed slow down, changes in appetite hormones constitute a behavioral barrier that is often more difficult to manage in the long term. The idea that food becomes more rewarding (hedonic system) is supported by neuroscience studies on dopaminergic reward in calorically restricted subjects. The exaggeration here lies in the direct comparison 'food is better than sex,' which is a figurative metaphor to illustrate the intensity of survival circuits, not a measurable clinical fact. In sum, Norton's evolutionary explanation regarding the priority given to energy over reproduction is a solid theoretical framework that is widely accepted in behavioral biology.

the sources

1. 1Hall KD, Heymsfield SB, Kemnitz JW, et al. 2012
2. 2Rolls BJ 2009