DEAR DR. DONOHUE: I’m a high-school senior, and I have played varsity girl’s basketball for three years. I have a bit of a weight problem. No one has said anything to me, not even my mom, but I can see that I need to lose some weight. I put myself on a low-carb diet. It’s that kind of diet OK for an athlete? – C.S.

ANSWER: It seems that everyone is on a low-carb diet.

Carbohydrates are the fuel that provides energy for most muscle action. That’s especially true of short, fast-paced movements such as sprinting down court to dunk a basketball. The body has a limited supply of stored carbohydrates. They’re kept in muscles as glycogen. The total amount of stored muscle glycogen is 300 grams (10.5 ounces) to 500 grams (17.6 ounces). That’s not a huge reserve. The liver is another depot for glycogen, and the blood is also a source of carbohydrate calories. The body’s entire carbohydrate bank amounts to 1,500 to 2,500 calories. If you are severely cutting back on your carbohydrates, you aren’t going to have enough on board to keep you at peak performance.

It’s true that fat is another source of energy fuel. It comes into play mostly when you’re operating at about 40 percent of your maximum speed. It cannot completely substitute for carbohydrate energy.

It doesn’t take long for you to deplete carbohydrate reserves. After 15 hours of not eating, the entire liver supply of carbohydrate is just about gone. Eight hours of sleep, therefore, empties the body of a considerable amount of its carbohydrate supply.

I advise you to abandon the dieting thing while you’re playing basketball. Are you really sure you’re overweight? I have never seen an obese basketball player, male or female. How about sending me your height and weight, and I can give you an idea of whether you have an accurate assessment of your body’s composition.

DEAR DR. DONOHUE: My 10-year-old broke his collarbone in a fall. The ends of the break are not touching. His treatment is only a sling. That has me wondering if the bone will heal correctly.

This boy is active in all sports. Will he always now have a weak spot in his collarbone? How long should he wait before resuming sports? – L.W.

ANSWER: The collarbone – the clavicle – is the only connection between the shoulder and the body. It keeps the shoulder propped up and prevents it from slipping backward. It’s the bone most often broken in childhood.

Treatment for a broken collarbone depends on where the break is. Most fractures are in the middle of the bone. Those breaks heal well with just a sling or a figure-8 bandage. Even if the two broken ends aren’t touching, the bone mends.

Your son won’t have a weak spot at the site of the break for the rest of his life. He might have a bump there after healing takes place, but that usually goes away in six months to 12 months.

The only one who can give you the time when it’s safe for your son to resume sports is the doctor who treated him. Most children with collarbone fractures can return to active sport participation in about five weeks. It depends on the break and the sport. Contact sports require a longer period off.

DEAR DR. DONOHUE: I’m 17 and wrestle. Last week during practice I was wrestling a kid who weighs 20 pounds more than I do. I had to struggle to move him around. After practice, I saw that my eye had blood in it. The white part was all red. I didn’t get hit in the eye, and it didn’t and does not hurt. I see perfectly. What is this? – R.R.

ANSWER: In all probability, it’s a subconjunctival hemorrhage. The conjunctiva is a transparent covering for the front of the eye. Beneath it (sub) are many fine blood vessels. Straining can cause them to break, and the result is a red blotch over the white part of the eye. Even a hard cough can cause those vessels to break.

The red color should go away in two weeks. If the eye begins to hurt or if your vision blurs, see the doctor right away.

DEAR DR. DONOHUE: I would really like to know how long we can safely keep and eat leftover potato salad. I threw away a bowl of it because it was on its fifth day. Am I overcautious? – M.J.

ANSWER: You can eat potato salad that’s been refrigerated from three to five days.

You’re not overcautious. You’re following a wise rule: “If in doubt, throw it out.”

Dr. Donohue regrets that he is unable to answer individual letters, but he will incorporate them in his column whenever possible. Readers may write him or request an order form of available health newsletters at P.O. Box 536475, Orlando, FL 32853-6475. Readers may also order health newsletters from www.rbmamall.com

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