In the evening, glucose tolerance is naturally a bit worse than during the day because of the circadian rhythm, which is why the usual hacks (vegetables first, vinegar before the meal, moving afterward) matter even more at dinner than at lunch.

noli's read

The claim rests on a named, checkable source: Morris, Yang, Garcia & Scheer, published in 2015 in PNAS, showed that the endogenous circadian system and circadian misalignment affect glucose tolerance through mechanisms separate from meal composition alone, the same amount of carbohydrate is handled less well in the evening. That's a solid, well-cited result in metabolic chronobiology. The hacks themselves (vegetables first, vinegar, movement after the meal) draw on the already well-supported food-order and vinegar playbook (Shishehbor et al. 2017), so the combination holds together: the circadian mechanism reasonably justifies applying these habits more strictly in the evening. The limit: Morris et al.'s study was done under controlled lab conditions (a forced desynchrony protocol), not an ordinary home dinner, so the exact size of the circadian disadvantage in everyday use is less precisely quantified than the mechanism itself.

the sources

1. 1Shukla AP, Andono J, Touhamy SH, et al. 2017
2. 2Shukla AP, Iliescu RG, Thomas CE, Aronne LJ 2015
3. 3Shishehbor F, Mansoori A, Shirani F 2017
4. 4Buffey AJ et al. 2022
5. 5Bellini A et al. 2023