While weight gain diets typically feature animal-derived foods like chicken breast and salmon, you don't need to eat meat to gain weight. And getting more of your protein from vegetarian sources might actually offer some health benefits, including a reduced risk of cancer and diabetes, as well as lower blood pressure. Use vegetarian-friendly foods to eat more calories than you burn to put on weight, and focus on plant-based foods rich in a few key nutrients -- including protein and iron -- for healthy weight gain.
The Basics of Weight Gain
No matter what type of diet you follow, weight gain boils down to your body's calorie balance. Adding mass to your frame requires getting extra energy, beyond what you need to maintain your weight. For most people, aiming for 250 to 500 extra calories daily will allow for weight gain -- up to 1 pound per week. If you gain weight easily, stick to the lower end of that calorie surplus to increase your weight slowly, at 0.5 pounds a week. If you're a "hard gainer" and have trouble packing on pounds, aim for the higher end of that range.
How many calories you need to maintain weight varies on an individual basis, since your body size, age and gender all affect how many calories you burn. A consultation with a nutrition professional can help you figure out how many calories you need and your new calorie target for weight gain. Alternatively, you can estimate your calorie burn using an online calculator; then add the calories you need to gain weight.
Getting Enough Protein as a Vegetarian
While protein is important for everyone -- since it supplies amino acids needed for immune health and cell growth -- getting enough protein is especially important when you gain weight. When you pair sufficient protein with a strength-training program, you trigger muscle gain that allows you to pack lean mass onto your frame, not just body fat.
Strength trainers need slightly more protein each day than the average person -- 0.8 grams per pound of body weight, or 124 grams for a 155-pound person. Several vegetarian-friendly foods can help you hit your protein target. A quarter-cup of textured soy protein -- sometimes called TVP -- has 6 grams of protein, while a half-cup of tofu or tempeh offers 10 or 16 grams, respectively. Eat a cup of cooked chickpeas, black beans or kidney beans for 16 grams of protein, or enjoy a cup of cooked lentils to get 20 grams of protein.
If you eat some animal products, eggs and dairy can increase your protein intake. A cup of fat-free cottage cheese, for example, offers 28 grams of protein, a half-cup of sugar-free yogurt supplies 5 grams, a cup of milk provides 8 grams, and each egg contains 6 grams of protein.
You'll also get smaller amounts of protein from other foods, including whole grains and veggies, that can help you reach your goal. Just make sure to include a wide variety of protein sources in your diet. Most plant-based foods are missing one or more amino acids you need for muscle growth, but combining several protein-rich foods can ensure you get the amino acids you need.
Other Considerations for Vegetarians
In addition to focusing on protein for your vegetarian weight gain diet, you'll also want to make sure you get enough omega-3 fatty acids and iron. Omega-3 fats boost your overall well-being by supporting brain function and reducing inflammation, and they might also support the tough training program you'll need to gain lean mass. Consuming omega-3 fatty acids can reduce delayed-onset muscle soreness -- that all-too-familiar muscle soreness you feel the day or two after hitting the weight room -- according to a study published in the Clinical Journal of Sports Medicine in 2009. By helping you recover from your workouts more easily, omega-3s can help you stick to a training program designed for weight gain. Iron also supports a weight-gain workout routine; it's involved in oxygen transport, so it helps supply your muscles with the oxygen they need to work hard during exercise.
Your body can't use the iron or omega-3 fatty acids found in plant-derived foods as easily as the iron and omega-3s in meat. However, you can still boost your intake of these key nutrients in a vegetarian diet. Make homemade dressings with flaxseed oil, snack on walnuts, add flaxseeds or chia seeds to cereals or smoothies, and buy omega-3 eggs to get more omega-3s. For plant-based iron, reach for lentils, kidney beans and tofu, and add cashews and potatoes to your meal plan. Serve your iron sources with fruits and vegetables -- such as bell peppers, broccoli, citrus and kiwi fruit -- to supply vitamin C, which boosts iron absorption.
A Sample Day's Menu
Start your day with a weight-gain friendly breakfast; try scrambled eggs with spinach, red peppers tomatoes and low-fat cheddar cheese, or a tofu scramble mixed with roasted potato chunks, green peppers and mushrooms. Drink a glass of nonfat milk or soy milk on the side for more protein.
At lunchtime, serve a quinoa-and-bean vegetarian chili -- with a spoonful of flaxseed stirred in for extra omega-3s -- on a bed of chopped kale, topped with cheddar cheese or Greek yogurt for added calories and flavor. Enjoy a piece of fruit or a handful of walnuts on the side or as a midafternoon snack.
For dinner, make a brown rice and lentil pilaf, seasoned with lemon juice, freshly cracked black pepper and chiffonade basil and mint. Serve your pilaf with a generous serving of roasted vegetables and a few slices of grilled tofu or tempeh. Up your omega-3 fatty acid intake with a chia spritzer, made by stirring a spoonful of chia seeds into sparkling cider or sparkling water to thicken the drink and add nutritional value.
The serving sizes you choose will depend on your calorie target and weight gain goals; for help planning a personalized meal plan, consult a registered dietitian.