If you are not losing weight over the long term, you are not truly in a caloric deficit; the absence of weight loss proves that your energy intake is not lower than your energy expenditure.

noli's read

The principle of conservation of energy (thermodynamics) is the basis of human metabolism, confirming that a caloric deficit is the necessary driver of mass loss. Research broadly supports the idea that individuals systematically underestimate their caloric intake and overestimate their energy expenditure during physical activities. The cited study (PMID: 1454084, a classic observational study published in the New England Journal of Medicine) perfectly illustrates this self-reporting bias. It is important to note that while the physics is indisputable, biology can vary: metabolic adaptations (a decrease in basal metabolic rate following prolonged restriction) can reduce the magnitude of the expected deficit. The assertion is therefore physically sound, but it sometimes fails to mention that the accuracy of caloric tracking is notoriously difficult for humans to achieve. This is not to deny the difficulty of the process, but to emphasize that estimation errors are the primary cause of the observed discrepancies.

the sources

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