Being underweight makes you vulnerable to illness. Elderly people who are underweight may be frail and susceptible to falls. Women may experience irregular menses and infertility. But if you are underweight, try to gain weight in a healthy manner to improve your appearance and overall well-being. Much like losing weight, healthy weight gain requires a focused diet and moderate exercise.
Step 1
Determine how many calories you need to sustain your current weight. Go to a site like MyPyramid.gov and select the "MyPyramid Plan tab" for an estimation of your daily calorie needs. Add between 500 and 1,000 calories to your maintenance number to gain 1 to 2 lbs. per week.
Step 2
Eat three meals daily. Start with a high-calorie breakfast containing healthy whole grains like whole-wheat toast or oatmeal, a protein like eggs, turkey bacon or plain yogurt and an unsaturated fat like chopped walnuts, olive oil or avocado. Do not skip lunch or dinner, and make each of these meals also contain a protein, healthy carbohydrate and unsaturated fat.
Step 3
Commit to eating two or more snacks daily. Snacking plays an important role in weight gain according to an issue of Today's Dietitian from January 2008. Approach these snacks as mini-meals composed of nutritious, calorie-dense foods rather than traditional snack or junk foods. Go for ½ cup of nuts and a banana for a 450-calorie snack, a cup of granola with low fat milk and strawberries for 500 to 600 calories -- depending on the brand -- or a meat and cheese sandwich on dense whole-grain bread for about 400 calories.
Step 4
Make yourself a high-calorie smoothie to drink daily, according to MayoClinic.com. Blend together frozen fruit, 100 percent juice, whey protein and honey. Add nuts or nut butter for a bigger calorie boost. Popular combinations include bananas and strawberries, coconut, pineapple and almond butter or peaches and orange juice.
Step 5
Drink low-fat milk or juice instead of diet soda or unsweetened tea. Skip sugared sodas and energy drinks, which offer calories but little nutrition.
Step 6
Perform resistance-training exercise a minimum of two times per week. Build lean muscle by using weights or moves like squats, push-ups and triceps dips, which will add pounds to your frame and make you stronger. Consult a certified trainer for assistance in designing a program for your needs. Replenish calories lost during your workout with a snack like cereal, a turkey sandwich or smoothie immediately after exercise.
Tips and Warnings
- If your schedule does not permit frequent meals, pack non-perishable quick snacks that you can eat quickly. Trail mix, energy bars made with natural ingredients and dates offer healthy nutrition and lots of calories in small servings.
- If you have experienced a sudden, unexplained loss of weight, consult your doctor.



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