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High-protein foods: The best protein sources to include in a healthy diet - Harvard Health
High-protein foods: The best protein sources to include in a healthy diet - Reviewed by Teresa Fung, ScD, RD, Contributor; Editorial Advisory Board Member, Harvard Health Publishing Including protein-rich foods in your diet is vital for maintaining overall hea
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High-protein foods: The best protein sources to include in a healthy diet
- Reviewed by Teresa Fung, ScD, RD, Contributor; Editorial Advisory Board Member, Harvard Health Publishing
Including protein-rich foods in your diet is vital for maintaining overall health and well-being. But how much protein do you need and what are the best sources of this essential macronutrient?
Why we need protein
Proteins are building blocks in the body. They make up bones, cartilage, muscle, blood, skin, enzymes, hormones, and vitamins. They're essential for growth and development, repair and build cells and tissue such as muscle, and play an important role in body processes such as blood clotting, fluid balance, and the immune response.
Proteins are made from amino acids. There are some amino acids that our bodies can make on their own. These are called nonessential amino acids. But there are nine amino acids that our bodies must get by consuming foods that contain them. These are called essential amino acids, and they are necessary for normal body functioning.
What foods are high in protein?
We can get protein from plant or animal sources. Protein in our diet can come from meat, dairy products, nuts, some vegetables, and certain grains and beans.
Try to eat a variety of protein-rich foods to ensure you are meeting your daily protein needs as well as getting the vitamins, minerals, and other nutrients needed for optimal health. Proteins that come from animal sources, such as meat, eggs, and milk, as well as soy and quinoa, are called complete proteins. This means they contain all the essential amino acids the body needs and are the highest-quality protein sources.
You can also get essential amino acids from plant-based foods. However, most plant-based proteins do not contain all of the needed essential amino acids, and so are called incomplete proteins. If you avoid animal proteins, the best way to ensure you are consuming a healthy mix of amino acids is to enjoy a variety of plant-based proteins through the day.
Foods that are particularly high in protein include:
Lean meats such as chicken, turkey, beef, and pork are excellent sources of high-quality protein as well as important nutrients like iron and zinc. To avoid unhealthy saturated fat, opt for lean or low-fat meat options such as lean ground beef, pork loin, or skinless chicken breasts.
Fish like salmon, tuna, and mackerel are not only rich in protein but also contain omega-3 fatty acids, which are beneficial for heart health. Look for seafood options that are lower in methylmercury, such as salmon, anchovies, and trout.
Dairy products like milk, cheese, and yogurt are rich in protein, calcium, and other essential nutrients. Greek yogurt is a great option, as it is high in protein as well as nutrients such as calcium, vitamins, and minerals. Dairy products can be high in saturated fat, so choose low-fat dairy options and limit the amount of cheese you eat.
Beans, peas, and lentils include kidney beans, pinto beans, white beans, black beans, lima beans, fava beans, soybeans, chickpeas, black-eyed peas, pigeon peas, split peas, lentils, and edamame. These plant-based foods are excellent sources of protein as well as fiber, folate, potassium, iron, and zinc.
Nuts and seeds include almonds, hazelnuts, walnuts, peanuts, chia seeds, pumpkin seeds, sunflower seeds, and peanut butter. They are not only rich in protein but also provide healthy fats, vitamins, and minerals. Nuts are high in fat and calories, so be mindful of portion sizes.
Eggs contain all of the essential amino acids, making them a complete protein source. Eggs are also a source of vitamins, minerals, healthy fats, and antioxidants.
Quinoa is a plant-based protein source that is also a complete protein. A cup of cooked quinoa provides about 8 grams of protein and 5 grams of fiber. Quinoa is also a good source of minerals such as manganese, phosphorus, and copper.
Soy products such as tofu and tempeh are good sources of protein, especially for vegetarians and vegans. One-quarter cup of tofu provides seven grams of protein.
How much protein should you eat daily?
For the average adult, the Recommended Dietary Allowance (RDA) for protein or the amount you need to meet your basic nutritional requirements and not get sick, is 0.8 grams of protein per kilogram of body weight, or 0.36 grams per pound. For a person who weighs 75 kg (165 pounds), that comes to 60 grams of protein per day. To determine your target daily protein intake, you can multiply your weight in pounds by 0.36, or use this online calculator. It's important to keep in mind that your daily protein need is not a fixed number. For example, your protein needs will fluctuate depending on your level of physical activity, and whether you are pregnant or breastfeeding.
Should I get my protein from animal or plant sources?
In order to get enough dietary protein in the most healthful way, nutritional guidelines have shifted away from specific amounts of daily protein, and toward the importance of eating healthier, protein-rich foods. It's important to think about the protein "package" when making protein choices because food containing protein also includes fats, carbohydrates, vitamins, minerals, sugar, sodium, additives, and other components. While meat provides high-quality protein, some meats also provide unhealthy amounts of saturated fats and sodium. If you eat meat, it's important to choose leaner meats and poultry. According to the United States Department of Agriculture (USDA), meats that are high in saturated fat include:
- fatty cuts of beef, pork, and lamb
- ground beef (75% to 85% lean)
- processed meats such as bologna, salami, sausages, hot dogs, bacon
- some poultry, such as duck.
A high-protein diet that is predominantly made up of red meat or processed meat is a cause for concern. Research has consistently found that both unprocessed and processed red meat are linked to higher risks of cardiovascular disease and diabetes. One meta-analysis found that replacing red meat with healthy plant proteins decreased the risk of cardiovascular disease.
For optimal health and nutrition, you should emphasize plant-based protein and protein from a variety of sources. The Mediterranean style of eating is one approach that emphasizes healthy protein sources.
Benefits of a higher protein diet
While most Americans consume more than enough protein, some people may benefit from a higher intake of protein.
To maintain or gain muscle mass
If you are over age 50, you should increase protein intake to one gram per kilogram of your body weight just to maintain muscle mass, which declines with age.
If you're trying to gain muscle mass, a higher-protein diet can help support muscle repair and growth. When you exercise, muscle cells break down. Protein from food helps to repair the damage, ultimately strengthening muscles.
To lose weight
The value of high-protein diets for weight loss remains controversial. However, one meta-analysis found that a high-protein diet could lead to weight loss and prevent weight regain after weight loss. The authors note the need for future studies that follow patients for longer than one year for more insight into this issue.
Other benefits
One study found that eating plant-based protein was associated with lower odds of developing cognitive decline later in life. For every 5% of calories that came from plant protein instead of carbohydrates, researchers observed a 26% lower risk for developing dementia in study participants.
How much protein is too much?
The idea of an upper limit of protein intake is controversial. Some experts believe the recommended amounts are too low. Others believe we are overconsuming protein. In general, the average person (not a body builder or an elite athlete) does not need high levels of protein and should not exceed 2 grams per kilogram; or about 125 grams per day for a 140-pound person. A main concern with taking in too much protein is an overall dietary imbalance. Consuming excessive protein may lead to inadequate intake of carbohydrates and fats. It's important to maintain a well-rounded diet that includes a balance of all three macronutrients for overall health. In addition, if you increase your protein intake without increasing physical activity, you may be taking in too many calories without expending enough, which could result in weight gain. There is also some evidence that eating a relatively high-protein diet can be problematic for individuals with pre-existing kidney conditions. A diet high in animal protein may pose a higher risk of kidney stones.
About the Author
Jenette Restivo, Health Writer; Assistant Director for Digital Content Creation and Engagement, Harvard Health Publishing
About the Reviewer
Teresa Fung, ScD, RD, Contributor; Editorial Advisory Board Member, Harvard Health Publishing
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