If you’ve been through a long illness or a period of emotional stress, your clothes may be baggy, and your family and friends might comment on how gaunt you look. A body mass index below 18.5 is considered underweight -- a condition that can affect your overall health. When you need to put on weight, you'll want to do it slowly and methodically to stay healthy. Talk to a doctor if you are unsure why you have lost weight or if you suspect you have an eating or body-image disorder.
Principles of Weight Gain
To gain weight, you'll need to know the basics of weight control. A pound of body weight equals roughly 3,500 calories, so, if you want to gain weight at a steady rate of 1/2 to 1 pound a week, you need to create a calorie surplus of 250 to 500 calories a day. That means you need to take in more calories than your body needs to perform basic functions and don’t burn them off through activity.
Even if your appetite is reduced, this process may not be as challenging as it sounds. If you normally eat only 1,200 calories a day, for example, bumping up your intake to 1,500 can be accomplished with a few strategic foods and will help you gain a little weight each week. Not everyone gains – or loses – weight in the same way, however, and you may need the help of a dietitian to find a formula that works for you.
Foods for Weight Gain
Avoid gaining all the new pounds as fat by paying attention to your food choices. You may be tempted to eat high-calorie foods that pack on pounds quickly, like fast food and other junk, but these supply calories without significant nutrients. And, if you have lost a lot of weight, you may be at risk for nutritional deficiencies.
Instead, focus on high-quality whole foods that are both calorie- and nutrient-dense. Fats, which supply 9 calories per gram, are good choices for weight gain. Go for healthy unsaturated fats from foods like avocado, nuts, seeds, olives and olive oil. Dried fruit is another nutrient-dense source of healthful calories. Lean protein foods help you build muscle as you gain weight; try fish, seafood, beans, legumes and dairy foods like yogurt and milk for the healthiest options.
Eating Strategies for Weight Gain
You can create a calorie surplus with just a few small changes to your diet. Try giving yourself slightly larger portions at each meal. You may find that “grazing” calorie-dense foods helps you achieve your goal better, however. If you’re recovering from an illness and don’t have much appetite, the Academy of Nutrition and Dietetics recommends eating five or six smaller meals in a day. Choosing quality foods that are also high in calories means it may not take much effort to add an extra 250 calories to your daily regimen.
For example, sprinkling just 1/2 ounce of chopped walnuts on top of your morning oatmeal or lunch salad adds 93 calories to your diet. Eating half an avocado as a snack gives you 182 calories, as does spreading a tablespoon of almond butter onto a small apple. A small box of raisins provides 129 calories.
Exercising While You Gain Weight
You can put on weight with diet alone, but without exercise, the pounds will likely come on in the form of fat. An exercise component will help you add muscle instead.
However, you’ll want to avoid getting too much aerobic exercise when you’re trying to gain weight, so you don’t burn off all the extra calories and undo your work. Instead, focus more on resistance training using weights, bands or machines, and aim for two to three sessions a week with exercises that target all your major muscle groups. Just as weight gain can be slow, so can the process of building muscle. Be patient and consult a trainer to help you devise a program that works for you.