Best foods that are high in protein

Protein is defined by the U.S. National Library of Medicine as the "building blocks of life" that "help your body repair cells and make new ones".

During digestion, proteins in food get broken down into three types of amino acids: essential, non-essential, and conditional. Essential amino acids are the type that are supplied by food because the body cannot produce it naturally. Non-essential amino acids are created by the body during the breakdown of proteins, while conditional amino acids are the type that are required when the body is affected by illnesses.

NBC News reports that according to registered dietitian nutritionist and spokesperson for the Academy of Nutrition and Dietetics Jessica Crandall, "Americans are getting what [they] need in a day, but it's not helping [them] meet [their] needs to perform better. There is recognized deficiency, especially in the morning."

NBC further reports that the Recommended Daily Allowance (RDA) for protein is 0.36 grams per pound of body weight. Crandall said, "You need closer to 20 to 30 grams per meal. If you don't have it at breakfast you have no reserves. Your body is going to start to break down your muscle."

The Huffington Post reports that protein is also valuable in keeping cravings at bay and building lean muscle. They also report that according to a new review published in Applied Physiology, Nutrition and Metabolism, it is also important to take into consideration where you get your protein, because not all protein sources are equal. In fact, animal-based protein sources such as meat, eggs, and dairy have most of the amino acids we need, but plant-based sources contain only some of the amino acids the body needs.

According to Rajavel Elango, a nutrition and metabolism researcher with the University of British Columbia’s School of Population and Public Health, it's best to consume a good combination of both animal and plant-based protein to get sufficient amino acids your bod needs. Here are some of the best protein sources that are easy to find in the grocery.

1. Eggs - Eggs contains 6 grams of protein and are great for any time of the day. In fact, Men's Fitness calls it a "versatile source of protein" because you can have it in the morning for breakfast, or after a workout. You can pack up the nutrition by making a garden omelette, too.

2. Yogurt - According to BBC Good Food, yogurt is a combination of casein and whey protein", and is great for lactose intolerant individuals, as most of the lactose content has been removed. Jim White, spokesman for the Academy of Nutrition & Dietetics and owner of Jim White Fitness training studios in Virginia told the Huffington Post, "Plain is your best option as fruit flavors can pack in loads of sugar", but if of course, you're free to mix in fresh fruit such as kiwis and strawberries.

3. Lentils and other legumes - Men's Fitness reports that lentils are a great source of fiber, with as much as 15 grams per cup, making you feel fuller faster. The combination of fiber and protein in lentils helps maintain a stable blood sugar, and the iron content in lentils make up for 80% RDI for men.

4. Pistachio and other nuts - BBC Good Food recommends the intake of 50 pistachio nuts, which contains 6 grams of protein, and sodium and potassium, which are great for replenishing the electrolytes lost during exercise.

5. Leafy greens and vegetables - According to the U.S. News & World Report's The Best Protein You Can Eat, vegetables such as kale, collard greens, and other leafy vegetables contain high levels of protein. In fact, for 70 calories of spinach, you can get 10 grams of protein. Men's Fitness also recommends edamame, which contains protein, carbohydrates, and unsaturated fat, which is great for snacking on the go.

For a quick, printable chart on protein contents of various food, check out Women's Health Magazine's easy guide.