For men and women who are looking to put on lean mass, the key is to combine resistance training with a high-calorie diet. The goal is to eat more than your body burns so you gain weight. This doesn't mean having a free-for-all diet where you eat a lot of pizza and burgers. To the contrary, you must eat nutritious, higher calorie meals and engage in muscle-building exercise to put on lean mass instead of fat. Athletes call this "bulking," but even non-athletes benefit from improving their body composition with added muscle.
Putting on lean mass takes discipline, consistency and hard work. A safe rate of weight gain for most people is 1/2 to 1 pound per week. Some well-trained athletes can gain up to 2 pounds per week.
To get started, calculate your basal metabolic rate, which is the number of calories you burn daily at rest.
The BMR formula for men is 66.47+ (13.75 x Weight in kilograms) + (5.0 x Height in centimeters) - (6.75 x Age in years).
The BMR formula for women is 665.09 + (9.56 x W) + (1.84 x H) - (4.67 x A).
Multiply your BMR by an activity factor to get the total calories you need per day to maintain your weight. If you're sedentary, multiply your BMR by 1.2. If you get light exercise, such as daily leisurely walking, multiply by 1.38. If you get moderate exercise 3 to 5 days per week, multiply by 1.55 and if you get high-intensity exercise most days, multiply by 1.7.
The easiest way of all to obtain your estimated daily calorie needs is to use an online calculator, such as the one from Iowa State University, where you plug in your weight, height, age, gender and activity level.
Once you know your daily calorie needs, start by adding 250 to 500 calories to your daily intake to gain 1/2 to 1 pound per week. Bodybuilders who are looking to put on serious muscle and who spend a lot of time doing strenuous exercise are known to increase by 1,000 or more. Adjust your caloric intake up or down for a few week to get the results you want, and scale your meal plan up or down accordingly.
Quick Weight Gain Foods
You don't need to slave over a stove all day to follow a weight-gaining meal plan. Quickly increase the caloric content of your meals with nutritious, calorie-dense foods. The top additions to a mass-building meal plan are nuts and seeds, nut and seed butters, unsaturated oils, whole grains, avocados, dried fruit and dairy. Always have these on hand, as they are staples in any weight gaining meal plan. Eat three main meals and three snacks, just as you usually would. To give you an idea of just how easy it is to bulk up your meals, consider that a regular-sized avocado contains about 322 calories; 2 tablespoons of peanut butter provide nearly 200 calories and 2 tablespoons of most unsaturated oils will deliver 240 calories. Simply add these foods to your meals and snacks, and you'll significantly increase your daily caloric intake.
Turbo Weight Gain Breakfasts
A quick, 700-calorie, weight-gaining breakfast is 1 cup of cooked oatmeal mixed with 1 tablespoon of flaxseed oil, along with 1 ounce of whole almonds and 1 cup of milk. As you can see, you don't need to gorge yourself on a lot of food. You're essentially having an oatmeal breakfast, but with some added calorie-dense foods.
Another 700-calorie, mass-gaining breakfast that's quick to make is a three-egg omelet made with spinach, mushrooms and 3 ounces of feta cheese, along with Greek yogurt and a slice of whole wheat toast.
Quick, High-Calorie Lunches
Weight-gain lunches are also quick and easy, once you know which foods are calorie dense. A quick, mass-gaining lunch is an egg salad sandwich on wheat bread, with a 1-ounce drizzle of sesame oil, a side of Greek yogurt and a 1-ounce handful of cashews. This protein-packed lunch contains around 850 calories.
Another lunch for a weight-gain meal plan that you can make in no time is a 6-ounce grilled chicken breast sliced and stuffed in a 6-inch whole-wheat pita with spinach, alfalfa and half an avocado drizzled with 1 tablespoon of flaxseed oil, along with a 2-ounce side of banana chips. This nutrient-dense lunch packs more than 1,000 calories.
Fast Mass-Gain Dinners
When you need to make fast dinners that are loaded with nutrients and calories, use quick cooking methods such as broiling. You can broil a single serving of meat in 10 to 15 minutes. One quick dinner idea for gaining is an 8-ounce broiled pork chop drizzled with 1 ounce of olive oil, a 1-cup side of brown rice and a half-cup of black beans, for a total of nearly 900 calories. Another weight gain dinner you can make in a snap is broiled sirloin sliced over a 1-cup bed of whole-wheat pasta and a 1-cup side of rice, which provides around 900 calories. Another way to save time is to prepare foods that take longer to cook -- such as sweet potatoes -- at the beginning of the week. Cook several servings at once. This way, when you want to add a sweet potato to your meal, simply reheat it quickly.
Zippy, Calorie-Packed Snacks
Use sandwich bags and snack containers to create quick snacks you can grab from the fridge. Quick, high-calorie snack packs you can make include dried fruit -- a concentrated source of calories -- a variety of nuts and seeds, several pieces of low-sodium beef jerky, bananas and peanut butter, apples and cashew butter and trail mix. Have a snack mid-morning, mid-afternoon and after dinner. Take snack packs with you when you're on the go so you will always have quick nutritious, high-calorie foods at the ready. If you have a particularly high-intensity workout regimen, it may help to add a mass-gain shake which is very high in calories.