Protein Foods: What They Are and How to Choose Them Wisely

What Are Protein Foods?

Protein foods are foods that provide dietary protein, an essential macronutrient. Your body needs protein to build and repair tissues, make enzymes and hormones, and support immune function. Protein is made up of amino acids; nine of these are essential, meaning your body cannot make them and you must get them from food. Eating a variety of protein foods helps ensure you obtain all the amino acids and nitrogen your body requires.

Common examples of protein foods include animal sources like chicken, beef, fish, eggs, and dairy, as well as plant sources such as beans, lentils, tofu, nuts, and seeds. The amount of protein in a serving varies widely—for instance, a 3-ounce serving of cooked chicken provides about 24 grams, while a half-cup of cooked lentils provides around 9 grams.

Sources: University of California, Davis, Department of Nutrition, Harvard T.H. Chan School of Public Health

Why Protein Matters

Protein is not just about building muscle. It plays a structural role in every cell, contributes to regulatory functions like hormone production, and can serve as an energy source when needed. A diet that meets protein needs supports growth and maintenance, from skin and hair to internal organs.

The amount you need depends on your body weight and activity level. Current U.S. guidelines provide both a minimum recommendation and a range that allows for flexibility, which we explain in the section below.

Sources: University of California, Davis, Department of Nutrition, Harvard T.H. Chan School of Public Health

Animal vs. Plant Protein: The Big Picture

Animal proteins—such as meat, poultry, seafood, eggs, and dairy—generally contain all nine essential amino acids in sufficient amounts, making them 'complete' proteins. They are also typically more digestible than plant proteins. Plant proteins, with the exception of soy and a few others, are often 'incomplete,' missing or low in one or more essential amino acids. However, eating a variety of plant foods across the day can still provide all the essentials, as the body can combine amino acids from different meals.

In terms of protein content, animal foods commonly provide 15–24 grams per 3-ounce serving, while plant foods typically provide 4–17 grams per serving. This difference reflects not only the food's nature but also portion sizes and preparation methods.

The choice between animal and plant sources also influences health. A large prospective study of U.S. health professionals found that higher plant protein intake was associated with lower overall mortality, whereas higher animal protein intake was weakly linked to higher cardiovascular mortality—particularly among those with at least one unhealthy lifestyle factor such as smoking or heavy drinking. Substituting plant protein for processed red meat, for example, was associated with a notable reduction in all-cause mortality risk.

The 2025–2030 Dietary Guidelines for Americans advise including a variety of protein foods from both animal and plant sources. Notably, the guidelines emphasize choosing meats with no or limited added sugars, refined carbohydrates, or chemical additives, and suggest swapping deep-fried cooking methods for baked, broiled, roasted, stir-fried, or grilled methods.

Sources: JAMA Internal Medicine (via PubMed Central), U.S. Department of Health and Human Services & U.S. Department of Agriculture, Harvard T.H. Chan School of Public Health

How Much Protein Do You Need?

The recommended amount of protein intake in the United States has evolved. The National Academy of Medicine sets a Recommended Dietary Allowance (RDA) of 0.8 grams per kilogram of body weight per day for adults, which serves as the minimum to prevent deficiency. For a 70 kg (154 lb) adult, that is about 56 grams daily.

However, the 2025–2030 Dietary Guidelines for Americans provide a higher range of about 1.2–1.6 grams per kilogram of body weight per day, reflecting evidence for optimal health and muscle maintenance. This range corresponds to roughly 84–112 grams for a 70 kg person and falls within the Acceptable Macronutrient Distribution Range of 10–35% of calories from protein.

Actual intake among U.S. adults, based on national survey data, is about 97 grams per day for men and 69 grams per day for women, which is well above the RDA and close to the newer recommended range. About two-thirds of this protein comes from animal sources.

• To find your personal target, multiply your weight in kilograms by 1.2 and by 1.6—aim for the middle of that range to meet general recommendations.
• If you are older or very active, your needs may be higher; the RDA might be insufficient for maintaining muscle mass in older adults, with some experts suggesting about 1.5 g/kg for this group.
• Consult a registered dietitian for personalized advice, especially if you have health conditions or follow a restrictive diet.

Sources: University of California, Davis, Department of Nutrition, U.S. Department of Health and Human Services & U.S. Department of Agriculture, Harvard T.H. Chan School of Public Health, USDA Food Surveys Research Group, via NCBI Bookshelf

Key Guides on This Site

This site offers in-depth guides to help you plan protein-rich meals and snacks. Start with our comprehensive list of high-protein foods to see protein content per serving for common animal and plant options. You can also learn about our editorial process and how we ensure accuracy in every article.

For any questions about your specific protein needs, talk to a healthcare professional or registered dietitian.