Whole Eggs

Whole eggs provide great protein content i.e. about 6 to 8 grams per egg and are also rich in vitamins, zinc, iron and calcium making them one of the most important foods for muscle building. Starting your day with more than just a couple of eggs can help you gain muscles and weight rapidly.
Water

Hydration is an important part of building muscle, even more important than most of the recommended mucle-building diets. Your body is 70 percent water and your muscle tissue is around 75 percent water. Keeping your muscles hydrated will help increase strength, energy levels and aid in proper digestion. Aim for about 0.6 ounces of water intake per pound of body weight.
Pineapple

Pineapples are a rich source of a protein-digesting enzyme named bromelein. It’s also been shown to reduce muscle inflammation, making it a great addition to your post-workout meal. Pineapple also adds taste to your plate making you like your food.
Chicken Breast

Chicken breast is one of the most recommended ingredient in almost all popular meals to build muscles. For every 100 grams of chicken breast you get 30 grams of protein with minimal fat. Chicken breasts are relatively inexpensive, easy to cook and can be served in many different styles.
Spinach

A couple of years ago, researchers at Rutgers University showed that the phytoecdysteroids contained in spinach may increase muscle growth up to 20 percent. You’d need to eat 2 pounds of spinach per day to reap the same benefits. Spinach can be a substitute for meat for vegetarian people who are on the run to gain muscles.
Sweet Potato

Sweet potatoes are one of the tastiest and more convenient options to replenish energy stores and fuel the muscle-building process. Sweet potatoes are rich sources of carbohydrates which are an essential nutrient for the body and they also help one add on additional muscle. Additionally, they're packed with vitamins and minerals to help you maintain normal blood sugar levels and keep you feeling fuller longer.
Almonds

Almonds provide a good source of protein and fat, but it’s the vitamin E in them that is most beneficial to your muscles. The powerful antioxidant fights free radicals and helps one recover quicker from workouts.
Chocolate Milk

In a study published in the International Journal of Sports Nutrition and Exercise Metabolism, it was revealed that chocolate milk was just as effective as sports drinks at increasing total exercise output and delaying exhaustion. Although it seems too good to be true, chocolate milk can indeed help you build more muscles.
Cottage Cheese

Some might consider this a dessert, but it's also one of the best muscle-building foods you’ll find. Just one cup of cottage cheese can pack 28 grams of protein. And the snack is made up of a combination of fast and slow digestion proteins, so you can stave off hunger.
Broccoli

Add broccoli and other fibrous vegetables like asparagus, spinach, tomatoes, sweet corn, peppers, onions and leeks to your post workout diet. You should eat five to seven servings of fruits and vegetables a day, and you can't find a better source of vitamins, minerals and fiber than these. All you need to ensure is that you don't overcook your vegetables as doing so will decrease their vitamin and mineral content.