Why Big Caloric Deficits and Lots of Activity Can Hurt Fat Loss
Joyce Park stashed this in Fitness
Most fitness professionals are far from patient, scientific, or balanced in their approaches... so I like to shout out the ones I find who are. Lyle McDonald has a nuanced approach to why sometimes a low calorie - high cardio regime can backfire. Hint: it's always hormones!
Specifically, it's cortisol.
In any case, dieting in general is a stress. And of course training is a stress. And the more extreme you do of each, the more of a stress occurs. And I suspect that a lot of what is going on when folks try to combine excessive caloric deficits with massive amounts of activity is that cortisol just goes through the roof (there’s another issue I’ll come back to at the end that relates to this). Simply, you get these massive chronic elevations in cortisol levels.