How much protein do you really need?

By John Murphy, MDLinx
Published December 3, 2018

Key Takeaways

Many recent articles and reports have advocated high protein, low-carb diets. So, if you recommend such a diet, or you’re on one yourself, you may wonder how much protein is enough—or how much is too much?

The answer, as established by the National Academy of Medicine, is that the Recommended Dietary Allowance (RDA) of protein for adults is 0.8 g per kilogram of body weight.

To determine your RDA for protein, multiply your weight in pounds by 0.36. Or, try this online protein calculator. For example, the RDA for a very active, 45-year-old man weighing 175 lbs is 64 g of protein a day. For a little 85-year-old sedentary woman weighing 100 lbs, her daily RDA of protein is 36 g.

“The RDA is the amount of a nutrient you need to meet your basic nutritional requirements,” wrote editor Daniel Pendick on the Harvard Health Blog. “In a sense, it’s the minimum amount you need to keep from getting sick—not the specific amount you are supposed to eat every day.”

How much protein are you supposed to eat every day?

A daily protein intake of about 1.0-1.2 g/kg of body weight is beneficial for healthy metabolic function, according to research supported by members of the Protein Summit 2.0. That is, about 10% to 35% of your total calories in a day should be protein, they wrote.

The Protein Summit 2.0 was a meeting in October 2013 of more than 60 nutrition researchers and experts from the United States and around the world to determine the optimal protein needs for human health. It’s important to note that the summit was sponsored by beef, egg, dairy, and pork industry groups, but it resulted in scientific reports that were independently published in a special supplement to the American Journal of Clinical Nutrition.

A metabolically beneficial protein intake for an average adult should be 25-30 g per meal, according to the Protein Summit’s researchers. Older adults might want to eat a little more because they don’t metabolize protein as well as younger adults, they recommended.

“As a result, modestly higher intakes of high-quality protein (1.0 g/kg to 1.5 g/kg per day), evenly distributed throughout the day, may maximally stimulate muscle protein synthesis, thereby contributing to maintaining muscle mass in older adults,” they wrote.

How much protein do we actually get?

So, are Americans getting enough—or too much—protein? The average protein intake for US adults is 1.2 g/kg to 1.5 g/kg per day, or about 16% of their calories in protein, based on 2003-2004 data from the National Health and Nutrition Examination Survey. Although these values exceed the RDA, they are well below the Protein Summit’s upper range of 35% of calories for protein.

Protein intake varies with age, sex, and activity level. For example, young men (ages 19-30) average 109 g of daily protein while elderly women (age 71 and older) get about 59 g per day, according to the data.

How much food is this?

It’s difficult for most people to picture in their heads how much protein is equivalent to, say, 0.8 g/kg of their body weight, or 25-30 g per meal, or even 59 g per day. So, here are some examples, according to the US Department of Agriculture Food Composition Databases.

  • ¼ cup almonds = 6 g protein
  • 8 oz skim milk = 8 g protein
  • 2 hard-boiled eggs = 13 g protein
  • 1 cup chili (with beans) = 16 g protein
  • 1/4 lb hamburger = 19 g protein
  • 7 oz plain low-fat Greek yogurt = 20 g protein
  • 10 chicken nuggets = 24 g protein
  • 10 oz T-bone steak (bone-in) = 78 g protein

“It’s also important to consider the protein ‘package’—the fats, carbohydrates, vitamins, minerals, and other nutrients that invariably come along with protein,” Pendick wrote. “Aim for protein sources low in saturated fat and processed carbohydrates, and rich in many nutrients.”

For example, 10 chicken nuggets have 24 g of protein but they also come with 26 g of fat. Two hard-boiled eggs provide 14 g protein but only 10.6 g fat, while chili has 15.7 g protein with only 9.6 g fat. So, chili provides less protein than chicken nuggets, but considerably less fat as well.

As with any approach to better dietary health, educating yourself as well as your patients on these variables before making food recommendations and choices is always a good idea.

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