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Dieting and Poor Training Performance
Submitted by Runner58 :: Sat Apr 02, 2005 12:34 am
The only proven way to extend life is to reduce caloric intake (with adequate nutrition). What’s that got to do with training and dieting? Dr. Marc Hellerstein (UC Berkeley) investigated the ‘why’ behind the food-longevity link by varying the caloric intake of mice and studying their rate of cell division. Bottom-line: eating less lowered cell proliferation rates. Still don’t get it? Well, training damages cells; cell growth is thus a necessary component of recovery, which, in turn, is the critical half of the stress+rest=progress formula. So if you’re cutting down on calories while training hard, you are probably slowing down your recovery rate and thus your improvement rate.
This new research is unrelated to the most common reasoning justifying the often-observed fact that training hard while dieting doesn’t work. The usual story (which is probably also correct), is that you deplete your glycogen during training and need lots of calories to replenish them, with complex carbs being a particularly efficient way of doing this (proteins take longer to break down into compounds that can be converted to glycogen inside muscles, which is why a lo-carb diet is particularly detrimental).
Hellerstein does not draw the food and training progress link since his focus was on cancer. He declared a eureka since fast cell growth is associated with higher chances of cancer.
Hellerstein doesn't know why cell growth is dampened, but guesses it is related to metabolic effects. "I think that a tremendous signal kicks in" when ones is fasting (dieters of the world to Dr.Hellerstein, "Duh"). One possible signal carrier, according to Hellerstein, is growth factor type 1 (IGF-1) -- an insulin-like protein promotes cell division. Previous animal research has shown that calorie restriction reduces blood levels of IGF-1.
