It's absolutely true!!! (and equally frustrating)
I have my calories lean, I work-out like a demon and I have to fight like heck to lost 1/4-pound per week! And then my jack-ass brother comes along and boasts about how those obese fatties on Worlds Greatest Loser can lose upto 14 pounds in a week. Sheesh!~
But yeah....your body will sorta adjust & acclimate to your exercise. It used to take me 1,400 calories to do my 14.4 mile mountain bike loop, and now I can do it in about 850 calories! (using heart-rate monitor with calorie-counter to measure). Well, let's think about it...now I'm carrying about 50 less pounds; 50 pounds doesn't move itself, no longer do I need to generate/burn the energy to move that weight. My muscles have grown, my body has adapted and I'm doing it much more efficiently. Bottom line is, less weight on your body means less demands to move it and less demands to support it.
From what I'm gathering, the body has several mechanisms to deal with what it perceives is a scarcity of food....it doesn't know you're trying to get ripped & fit, it just knows you're depleting your energy bank. And you'd better exercise, cause excess lean muscle tissue is an energy user even when it sits unused; you're body will shed it if you don't keep a need/toll placed upon it.
So yeah, it gets tougher...but it is what it is and we press on in the face of caloric adversity.
