Whether you are genetically underweight (have a BMI below 18.5), have a medical condition that makes it difficult to stay at a healthy weight, need to gain pounds during pregnancy, or would simply like to add lean muscle mass, putting on healthy weight can require just as much discipline and strategy as losing weight does. Since you don’t want to end up gaining fat, you can’t just stuff yourself with cheeseburgers and milkshakes and call it a day. A better strategy is to fill up on nutrient-dense foods at regular times throughout the day, adding 250–500 calories per day on top of what you would normally eat. Depending on your activity level and genetic makeup, these extra calories should help you gain half a pound to one pound per week. And activity is still important, although you may want to emphasize strength training over cardio to help you build lean muscle. Here are some guidelines to keep in mind.
Eat frequently. When you’re awake, don’t go more than four hours without eating. This translates to five or six mini-meals/hearty snacks throughout the day, which ensures that your body has a steady supply of nutrients. Plus, it’s much easier to consume the necessary number of calories than if you try to devour three very large meals a day.
Choose nutrient-dense foods. Some of your best bets are nuts and nut butters, seeds, whole grains, lean protein, olive and canola oils, and unsweetened dried fruit. Small portions of these pack a lot of calories and a wide range of nutrients. You need a balance of carbs, protein, and healthy fats to help fuel and build muscle, but watch out for added sugars.
Drink your calories. We do not register calories consumed in drinks the same way we do from foods, so drinking 100% fruit juice, milk or milk substitutes (soy, almond, rice), and smoothies are a great way to sneak in extra calories without feeling like you’re stuffing yourself. Smoothies, in particular, are good choices because they can include fruit, vegetables, lowfat dairy, nuts or nut butters, freshly ground flaxseed, oatmeal, and instant breakfast or meal replacement/protein powders. Need some inspiration? Check out these 20 recipesfrom Prevention magazine.
Boost the calories of foods you already eat. Make your hot cereal with milk instead of water. Top dishes with a little grated cheese, and add cheese to sandwiches. Use two tablespoons of nut butter instead of one. Stir chopped nuts and freshly ground flaxseed into your yogurt. Choose dense cereal (as opposed to puffed or flakes) and top with nuts and fruit. Stir lentils or beans into soup and garnish with croutons.
Stay active! To make sure that the extra calories you’re consuming are converted to lean tissue instead of fat, it’s critical to continue exercising. Cardio is important for overall conditioning and heart health, but limit workouts to 2–3 times per week, for 20–30 minutes at a moderate intensity. (Note: if you are an athlete trying to gain weight, follow your recommended training plan but increase your daily calorie intake by 500–1,000 calories, or more if necessary, to make up for the extra energy expenditure.) Strength training will help you build muscle, so plan on doing strength exercises at least twice a week for 30 minutes or more, taking a day off between sessions to let muscles rest and rebuild. Make sure you work all your major muscle groups: chest, upper back, shoulders, biceps, triceps, quadriceps (quads), hamstrings and glutes, calves, and abdominal muscles. Check out the Mayo Clinic website for sample exercises.