Ask the Nutritionist: How Much Protein Do I Need, Really?

Protein for vegetarians is always a hot topic. We’ve all heard someone say it’s not possible to get enough protein without eating meat – and even though we know that’s not true for most people, there can be some questions about the details. Questions like, just how much protein do I need to be getting, anyway? We asked nutrition expert Katherine Tallmadge for the scoop.

So, How Much Protein Do I Need?

Protein is the major component of all of your body’s cells, and you’re right, it’s important to make sure you’re getting enough. Recent research indicates that we may need more than previously thought. The recommended dietary allowance (RDA) for all adults is 0.37 grams of protein per pound of bodyweight, or about 15 percent of your daily calories.

But you probably need more if you exercise, if you’re dieting, and as you age. One dramatic study of 855 people found that those who ate just the RDA of protein had alarming bone losses compared to those who ate more than the RDA. Those who ate the least protein lost the most bone mass—4 percent in four years. People who ate the most protein (about 20 percent of calories) had the smallest losses—less than 1.5 percent in four years, reported the Journal of Bone and Mineral Research in 2000. Although the study was done on older men and women, the results may be important for all adults.

“When you’re young, you need protein to build bone. After age 30, you need it to keep bone from being lost,” says Kathleen Tucker, associate professor of Nutritional Epidemiology at Tufts University. “Keeping bones strong is a life-long effort.”

Dieters, take note: New research has found that a protein-dense diet may be essential for weight loss. It helps maximize fat loss while minimizing muscle loss. That’s important because “losing muscle slows your resting metabolic rate—the speed at which your body burns calories. That makes it harder to maintain a healthy weight and lose fat,” says William Evans, director of the Nutrition, Metabolism, and Exercise Laboratory at the Donald W. Reynolds Center on Aging at the University of Arkansas for Medical Sciences.

Many of us don’t get the RDA for protein. Roughly 25 percent of adults over age 20, and 40 percent of those age 70 and up, fall below it, according to United States Department of Agriculture (USDA) statistics, let alone eat enough to protect bones or muscle. And thin women, dieting women and elderly women—who are especially vulnerable to the ravages of bone and muscle loss—are notoriously low on protein. “Losing muscle causes older people to become weak and frail,” says Evans.

“It seems pretty clear that older adults may need more protein,” agrees dietitian Reed Mangels, nutrition advisor to the Vegetarian Resource Group and co-author of The Dietitian’s Guide to Vegetarian Diets. “Older vegetarians need to concentrate on eating protein-dense foods, such as legumes and soy.”

Based on the new findings, I now recommend that moderately active people and older adults increase their protein to about 20 percent of their calories, or 0.45–0.54 grams per pound of ideal body weight.

“Protein is not only essential in the body’s development but, just as important, in the maintenance of our body as we age. Plant proteins are the healthiest source of those proteins,” says Pat Mitchell, CEO of Svelte.

For what this means in real food, see below. If you’re an athlete or bodybuilder, you may need even more. On an individual basis, you can use the following formula to figure out your protein needs.

Whether you’re looking to fuel a training regimen or to simply get more plants into your diet, Satisfying Plant-Based Protein Swaps, exclusively on Outside Learn, has you covered. Lauren McNeill, RD, will show you how to swap delicious plant-based proteins for the animal proteins you may be used to. You’ll learn why protein is important, how much you need, what the best sources are, and much more.

RELATED: Guavas, Chia Seeds, and 6 Other Meat-Free Foods That Are Surprisingly High in Protein

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