DEAR DR. DONOHUE: I am a 17-year-old girl, and my weight varies from 110 to 120 pounds. I am 5 feet 8 inches tall. Five years ago, when I was going through puberty, I weighed 130, and that was about perfect for me. Now I just can’t gain any weight. I am not anorexic. I eat plenty. Do you have any advice? – T.W.

ANSWER: Although it’s the goal of fewer people than weight loss, weight gain can be almost as big a problem. Partly that has to do with the energy-burning of bodies that are still growing even at age 17. Partly it comes from genetic programming and a person’s metabolism. The answer is straightforward. You must take in more calories each day than you burn to gain even an ounce.

Buy an inexpensive booklet that contains the calorie content of food in an understandable form – in ounces or servings, and not in grams. For one week, keep a daily count of how many calories you eat, and divide the weekly total by seven to give you the average number of calories it takes to keep your weight at its present level.

If this is too much of a bother, multiply your weight by 6.7 and then add 487. Then multiply that number by 1.6. In your case, the result is around 2,000 calories – the daily calorie requirement to maintain your body weight.

By eating 500 more calories a day, you should gain one pound a week, provided that your digestive tract is in good working condition and your thyroid gland is not in overdrive. Snack on high-calorie food between meals and at bedtime, but don’t cut down the amount you eat at mealtime. Nuts are a good example of calorie-dense food. One ounce has about 160 calories. A half-cup of raisins has 220; a plain bagel, 164; a half-cup of ice cream, 205; 1 tablespoon of peanut butter, 95. A 16-ounce milkshake weighs in at between 400 and 600 calories. It’s not difficult to add an extra 500 calories to anyone’s diet.

DEAR DR. DONOHUE: I am a 48-year-old male whose job involves a lot of walking. For exercise I like to do extra walking or running. My problem is bunions. When I walk more than half a mile, my bunions swell, get red and are excruciatingly painful. I have had to eliminate my exercise. What can I do, short of surgery? My understanding is that surgery isn’t always good. – M.B.

ANSWER: Bunions are bumps on the big toe where the toe joins the foot, on the side away from the other toes. The big toe drifts inward toward the next toe. In addition to the obvious bump, much of bunion pain comes from a cushioning bursa in that location. The inflamed bursa – about the size of a dime – fills with fluid and becomes quite tender.

Blame heredity for some bunions. Bone misalignment is another cause. Cramming feet into narrow shoes also contributes to bunion development.

You must wear shoes that provide ample room for the fronts of your feet so that the bunions aren’t rubbing against the sides of the shoes with each step you take. Also make sure that there is a half-inch clearance between your longest toe and the front of the shoe.

If your foot turns inward when it hits the ground, as it does for many bunion sufferers, an arch support can stop that excessive twisting and take pressure off the bunion.

Padding helps. The pad must not be so thick that it’s adding to pressure on the bunion. Moleskin makes a good pad. There are plenty of other materials that can serve just as well if you can’t find moleskin.

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.