While some people struggle to keep weight off their bodies, others have trouble putting on weight. A person who is underweight has a body mass index below 18.5. Being underweight can lead to serious health problems, including osteoporosis, fertility problems and a weak immune system. If you are underweight, you can do certain things to gain weight.
Eat More Often
Add 500 calories to your normal daily intake to gain one pound a week. One way to increase your caloric intake is to consistently eat three larger-than-normal meals and to eat at least two snacks during the day.
Eat Calorie-Dense Foods
Eat healthy foods that are high in calories. Peanut butter, nuts, avocados and granola are healthy foods that high in calories. Avoid eating high-calorie foods with no nutritional value, such as pastries, chips, white bread and candy. Eating junk food may seem like a fun way to gain weight, but it only makes you put on weight in an unhealthy way and may make you more tired throughout the day.
Train with Weights
Because muscle weighs more than fat, adding muscle to your body helps you gain weight. Strength training helps exercise your muscles and add extra bulk to them. Strength training also helps ensure that the excess calories you are consuming don't turn into fat but rather build muscle to improve overall health.
Consume a Small Amount of Alcohol
Drink a little bit of alcohol before dinner to increase your appetite. Have a small glass of wine or half-ounce of liquor with juice. Don't go overboard with drinking alcohol, because it can be detrimental to your health. Consult with your doctor before consuming alcohol, especially if you are taking medication.
Drink Liquid Calories
Drink juice. Juices are high in calories and have more nutritional value than soda. If you are unable to consume enough calories from your meals, try drinking a glass of juice during your meals and between meals to add extra calories to your daily intake. Four glasses of juice per day can add a few hundred extra calories to your diet.