I first wrote this as a reply in this thread and now I'm looking at it, I think it's relevant to the article as a whole -- sugar, insulin, calorie reduction, stress, fitness in general. I believe that the "diet" mentioned in the article is in effect a calorie-restriction one. > Losing weight and gaining weight is simple physics. > you are losing weight because you are consuming less calories. This is only true in the…
This is a fairly pernicious half-truth, even among fitness types, which is used to explain away much more than it should. It has some truth to it, but people use it way too easily to handwave away differences in intake. It's true that the metabolism adjusts, but that adjustment is slow and limited. The gap between "slow metabolism" and "fast metabolism" people is only a few hundred calories/day at the extremes. Your body isn't going to suddenly start burning an extra 1k calories/day.
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4535334/
In this study, they found that the RMR for women varied between 0.721-0.926 kcal/kg/hr (1730-2222 kcal/day @ 100kg), men varied between 0.791-0.969 kcal/kg/hr (1898-2325 kcal/day @100kg).
That is, if you're the slowest of "slow metabolism" people, you pretty much just need to deny yourself a single box of M&Ms to match the net energy expenditure of the fastest of the "fast metabolism" people. Hitting average is even easier.