Ask the Doctors

Dear Doctor: So many articles seem to be about weight loss, but I'm actually underweight. I eat enough, live a healthy lifestyle and exercise. But I'm 5 feet 1 inch tall and weigh 100 pounds. The charts say I need to gain about 12 pounds to be normal. How can I gain weight?

Dear Reader: The first thing we would suggest is that despite the various charts, you may already be at the appropriate weight for your metabolism. No two people are exactly alike, and the fact that your body weight doesn't conform to a calculated average doesn't automatically mean you are underweight.

A useful tool for gauging healthful weight is the body mass index, or BMI, and it's going to hold a happy surprise for you.

BMI is a simple calculation that indicates the likely proportion of lean muscle to body fat based on a person's weight and height. It doesn't directly measure the percentage of body fat -- that requires a skin caliper test, hydrostatic weighing or a bioelectrical impedance test, to name a few. But research suggests that BMI correlates as strongly to various metabolic and disease outcomes as does the measure of body fat.

A BMI that ranges from 18.5 to 24.9 is considered to indicate a normal or healthy weight. The good news is that at 5 feet 1 inch and 100 pounds, your BMI is 18.9, which puts you into the healthy range. However, if you would feel more comfortable with a few more pounds on your frame, we have some suggestions.

Because a high proportion of body fat puts you at greater risk of heart disease, Type 2 diabetes, hypertension and certain cancers, you want to be careful that the weight you gain is a healthful proportion of muscle and fat. That means splurging on high-calorie/low-value foods like processed snacks, sugary sodas, candy, pastries, fried foods -- you know the drill -- is not the way to go. Instead, approach your weight gain with the same focus, research and precision of a successful weight loss plan.

-- Keep a food diary and figure out how much you eat per week. Then, pick a reasonable amount by which to increase your food consumption.

-- Instead of eating three big meals per day, aim for four to six small ones. This gives you additional opportunities to eat more without getting too full.

-- Skip the low-calorie and fat-free versions of the foods you typically eat. Whole-milk yogurt, 2-percent milk, butter rather than margarine, salad dressings made with healthful oils -- these are your allies.

-- Add calories to the foods you already enjoy. Try mixing nuts into your yogurt, spreading nut butters on your toast, sprinkling cheese into your scrambled eggs and jazzing up your salad with avocado.

-- Stick with healthy proteins, but choose those that are more nutrient-rich. Salmon, for instance, is higher in calories, and delivers healthy omega-3 fatty acids.

Ease into your new eating regimen gradually. You want it to be sustainable and enjoyable. And we recommend that you make your family doctor a partner in your new endeavor. Good luck!

(Send your questions to askthedoctors@mednet.ucla.edu, or write: Ask the Doctors, c/o Media Relations, UCLA Health, 924 Westwood Blvd., Suite 350, Los Angeles, CA, 90095. Owing to the volume of mail, personal replies cannot be provided.)

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