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How changing diets for different sports affects metabolism

Running & Fitness
Saturday, August 1, 2020

I was looking through a few of my fitness and physiology of exercise books for a possible topic for this week’s article. One topic that caught my attention was one of eating disorders in athletes. I never really paid much attention to the role food and eating habits play in athletics. I have practiced a number of different “diets” for different sports without really thinking about the consequences of a strict diet. 

There are some sports that have weight classes for the athletes to compete. The most obvious one was wrestling. In amateur competition there are nearly 10 different weights that athletes fit into. Weights range from 95 pounds to super heavy weight for wrestlers weighing over 270 pounds. Women’s gymnastics is well known to have very strict weight control. A lighter, stronger woman can do more of the difficult moves. One problem women have in gymnastics is that when she starts to mature and her body shape changes from that of a 12 year old protégé to that of a young woman, her center of gravity changes, and some stunts become more difficult. Strict diets can delay the change a little. Bodybuilders, both men and women, have to diet down to a body fat percentage of around 2%. A very thin skin covering allows the muscles to show through better under the spotlight when they compete. Most research recommends that body fat percentage for men should not go below 8%, and for women 12%. The starvation diet that many go on will slow the basic metabolism down so that in order to keep losing body fat the bodybuilder has to restrict their diet even more. After the contest, the metabolism is so low and efficient at using food that any food they eat will be converted to replace the fat and muscle lost by the strict diet. I knew one woman bodybuilder that started out at 160 pounds. She dieted down to 115 pounds. Two weeks after her meet she weighed 150 pounds while she still restricting her diet. I told her she just needs to keep working out and her metabolism will return in about four months and to keep eating a balanced diet. I had a classmate that went to the United States Naval Academy and played 150-pound football. In high school he weighed 165 pounds, so he had to diet down. I saw him about 15 years later and didn’t recognize him. The man standing before me weighed 220 pounds and was bald. I am not sure if the diet caused the hair loss, but the change from 165 pounds to 220 pounds made it difficult in recognizing him. 

Runners know that a lighter weight takes less energy to race and they can run faster. Runners that plan on running a marathon try to do a “carbo load” diet before the marathon. Runners try to eat as much carbohydrates the day before the race to store extra energy. The usual pre-race meal is spaghetti, or some sort of pasta, ranging from pancakes to candy bars. The problems with weight loss that happen can be quite serious. Women especially have a problem when their menstrual cycle stops. Men have some of the same consequences from eating a high carbohydrate diet with limited amount of protein. When a person loses weight it comes from both fat and muscle. Loss of muscle strength is not what a runner needs. The addition of strength exercises can help with this problem. Too many runners think that if they lift weights they will build big muscles and gain weight. A person can lift weights to get stronger and not gain weight. They have to follow a program of strength for running and not bodybuilding or power lifting. One other problem from a strict diet for runners is that they tend to lose bone strength. There are many documented accounts of runners coming down with shin splints in their lower legs from bone loss. Recovery from this injury is basically a program of staying off the legs and no more running until the bone recovers its strength.

Having participated in wrestling (157 pounds), bodybuilding (155 pounds), weight lifting (171-190 pounds), gymnastics, running marathons (152 pounds), I went through those restricted diets. I never thought that I had an eating disorder, but in each sport my diet was changed. One thing that is mentioned in articles is that as you age, your metabolism slows down. I guess between the eating disorders in my youth, my once-upon-a-time very active exercise lifestyle, and now getting older, is the reason my trying to lose that 15 pounds for four years I am still at the same weight. Time to up the activity level.

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