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17.10.2010


Crash diet damages digestive system, not muscles: animal study

You skip meals for a few days. And if that doesn't get you down to your ideal weight, you don't drink any water on the day before a competition. In sports where weight is important this is a common practice. Japanese sports scientists did an animal study to examine what a crash diet like this does to body composition.

The Japanese used young male rats for their experiment. Because they were interested in the effects of diet on athletes, they got their rats to train. Six times a week the rats did climbing exercises.

The rats in the control group got to eat as much as they wanted for 16 days. [C] Another group of rats were put on a restricted diet for the same amount of time, and gradually lost weight. [S] A third group of rats ate unrestrictedly for 13 days and then were given no food at all for the next 3 days. [R] And on the last day of the experiment the R group rats were given no water either.

The figure below shows that both slimming strategies resulted in a similar weight loss.


Crash diet damages digestive system, not muscles: animal study


The R group's crash diet led to slightly more fat loss and slightly less lean body mass loss than the slower S group diet, but the differences between the two groups were not statistically significant.


Crash diet damages digestive system, not muscles: animal study


What was significant was the difference between the effect of the S and R diets on the digestive organs. The liver, stomach and small intestine of the rats that had lost weight on the crash diet were considerably lighter than those of the rats who lost fat mass more gradually.

So just how unhealthy is this? The Japanese don't answer this in the study here, but they do in another article. We've read this too, and it clears up some questions.

Tune in tomorrow. Same ergo-time. Same ergo-channel.

Source:
J Clin Biochem Nutr. 2009 Sep; 45(2): 185-92.