no activity + 1800 kCal/day = 1 lb weightloss/week
training + 1800 kCal/day = 0 lb weighloss/week
note: macronutrient composition constant in both conditions.
Years ago I read Why Zebras Don't get Ulcers by Sapolsky which is an excellent book detailing the horrors of cortisol (the stress hormone). At the time I was involved in research on an intervention designed to reduce stress and we were using salivary cortisol levels to measure our outcome. I think I need to re-read this book from a different perspective.
A friend pointed out that training -- particularly the kind of training that goes into endurance events -- raises coritsol. It is a stress on the body. This is so obvious that I totally didn't think of it.
Dieting itself is a stress. And my body is already mad at me. If you want to piss off your body, gain a bunch of weight and then lose it. Fun times.
So dieting is stress. Training is stress. Plus sometimes life is stressful.
I have always found it easiest to lose weight in the off season. I assumed it was because I was so hungry all the time when training on a high carb diet. But now I am not hungry all the time -- or really ever -- and I am still not losing weight.