The problem
The same food does not produce the same result.
Nutrition is designed and sold by composition: grams, calories, ingredients. But the body responds to food as a signal, and the response depends on context: time of day, metabolic state, history. Large published studies have shown that people respond very differently to identical meals.
Noise makes it worse. Scattered snacks, irregular hours, stress and poor sleep create many small signals that keep the response below the threshold.
Example: the PREDICT study (Berry et al., Nature Medicine, 2020) documented large person-to-person differences in post-meal responses to identical meals.