A caloric deficit does not work long-term because the metabolism slows down, making portion control ineffective for sustainable weight loss.

noli's read

This advice relies on the real phenomenon of metabolic adaptation, in which the body reduces its energy expenditure during prolonged caloric restriction. However, research, notably a meta-analysis (Hall et al., PMID: 29466592), shows that this slowdown is modest and never completely neutralizes a caloric deficit. Contrary to the claim, low-carbohydrate diets or intermittent fasting do not protect against this metabolic adaptation any more than other approaches (Trexler et al., PMID: 32986097). Furthermore, controlled studies (PMID: 29466592) indicate that when calories are equivalent, variations in insulin levels do not lead to significant differences in fat loss. Finally, the idea that fasting would stimulate autophagy in a way superior to conventional caloric restriction lacks robust clinical evidence (PMID: 34135111).

the sources

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