Lose weight, gain speed?
A recent NY Times article explored the connection between weight and athletic performance. Runners have long known that carrying extra pounds will slow them down, but does being lighter always result in faster racing performances?
The general rule of thumb is that a 1% decrease in body weight will lead to a 1% improvement in your race time. For example, if you weight 150lbs and your mile PR is 6:00, you could hypothetically lower your PR to 5:42 simply by losing 7.5lbs (a 5% reduction both race time and body weight). While its undeniable that lean athletes have an advantage, there is a breaking point where thinness can actually be detrimental to your performance. Consume too few calories and your body will start burning muscle for fuel, your energy levels will lag, and you may become deficient in important nutrients. So while science has given us guidelines (the 1% rule mentioned above), an individual’s “ideal racing weight” probably can’t be determined by a mathematical equation.
I always assumed that elite athletes didn’t think much about their weight. The top guys are running 100+ miles per week – they must be able to eat anything they want! As the protagonist in Once a Runner proclaims: “If the furnace is hot enough, it will burn anything.” So I was quite surprised to find out that top American marathoner Dathan Ritzenhein puts himself on a diet in order to reach his ideal racing weight – 121/122 lbs for his 5′8″ frame. The article states: “That weight is not a natural one for him, he said. If he were to stop training, he would weight about 127 or 128 pounds, and when he is training but not trying to control his weight, he is about 124 or 125.” I found this interesting, yet a little disturbing, but I suppose since Ritzenhein’s career depends on his racing performance it is understandable that he’ll do anything it takes to get the win. It’s really no different than a movie star losing or gaining weight for an important role. However, what does this mean for the rest of us?
If your goal is to simply finish a marathon or improve a 5K time, perhaps a cleaner diet and more focused training can provide the best results. But, what if your goals are more ambitious – to win age group awards, PR on the track, or qualify for Boston? If you’re a bit heavier, losing some weight might result in faster times, but the key here is: actually having those pounds to lose. If you’re already slim, trying to lower your weight below your natural set point is risky business. Those few pounds you dropped might be replaced with lethargy and fatigue. So unless you’ve got a contract with Nike, good nutrition and smart training will help you go farther than dieting. No slim fast or cabbage soup required.