Protein is one of three macronutrients needed in the diet to maintain health. It is a component of all living things. It is required by the human body for the most basic of cell activity, including that of bones, muscles and blood. Protein also helps maintain a healthy metabolism and strengthens the immune system.
Amino acids are the building blocks of protein. Much of the body’s communication systems rely on amino acids for things such as neurotransmitters and hormones as well DNA and RNA.
Amino acids are obtained through the diet in a variety of ways. Animal proteins are considered complete proteins as they contain the essential amino acids the body needs.
Plant proteins such as beans and legumes are incomplete proteins, which do not contain the essential amino acids but offer vitamins and minerals such as folate and magnesium. Dairy, nuts and seeds are all foods that provide protein as well as carbohydrates and fats.
Knowing the right amount of dietary protein to consume can aid in maintaining optimal health. Protein needs vary by individual based on age, sex, weight and activity level. In some cases, health status may also be a factor in determining the appropriate amount for you. With so many diet trends claiming results for weight loss, sustained energy and detoxification, it can be confusing to know the right balance.
While the USDA Dietary Guidelines for Americans do not make specific protein recommendations, the Dietary Reference Intake suggests 0.8 grams per kilogram of body weight. This would be a general recommendation. For those training or with high physical activity, a range of 1.5-2.0 grams per kilogram of body weight may be more appropriate. Because the body is using food to build and repair, it is important to consume your protein intake at several times throughout the day and not just at one meal.
To calculate your needs:
Step 1 — Measure your current weight.
Step 2 — Convert pounds to kilograms by dividing by 2.2. For example, 145 pounds divided by 2.2 pounds per kilogram equals 66 kilograms.
Step 3 — Choose activity level between sedentary (seated or lying all day with no physical activity, 0.8 g/kg), moderately active (spend most of the day sitting with occasional standing or walking and participate in moderate activity, 1.0 g/kg), very active (either standing or walking for most of the day or participate in physical activity such as exercising at the gym or attending spin classes regularly, 1.2 g/kg) and vigorously active (strenuous work or high intensity exercise each day, 2.0 g/kg).
Step 4 — Multiply your weight in kilograms by the activity level recommendation. For example, if you weigh 66 kilograms and are moderately active, your target protein consumption would be 66 grams per day.
You can find the amount of protein per serving on nutrition labels. For whole foods or other packaged foods you may search the USDA Food Composition Database at https://ndb.nal.usda.gov/ndb/. Apps such as Myfitnesspal, Bitesnap, Lose it or Chronometer also will calculate protein macronutrients based on your description or picture of food.
When evaluating an overall plan, a healthy adult protein intake should equal between 10-35% of calories per day. There are unique circumstances such as chronic kidney disease in which protein intake may be restricted. When making dietary changes, be sure to check with your physician or dietitian for personalized recommendations.
Food Protein (in grams)
3 oz. serving beef 21
3 oz. serving salmon or tuna 17
1 egg 6
6 oz. Greek yogurt 17
1 cup milk 8
½ cup cooked beans 8
2 tbsp. peanut butter 8