its well accepted that stress (and the rise in cortisol it causes) are certainly capable of shifting the bodies ability to burn fat. this is why certain supplements
have such a profound effect on fat loss. todays fat burners, for example are designed in a lot of ways to emulate clenbuterol and its effects on fat loss/anti-catabolism. dieting in and of itself can cause a significant uptick in cortisol levels, so keeping them in check using various methods (both legal and less than)
will ultimately help ones ability to reach low body fat levels.