The answer: Less than you think
Smoothies, shakes, supplements: There’s no shortage of products that come with promises to boost your protein intake. But do you really need that extra protein?
“I think a lot of people feel pressured by all the marketing out there, making them feel like their diet is protein-deficient,” says Douglas Paddon-Jones, Ph.D., a professor of nutrition and metabolism at the University of Texas Medical Branch.
Before you start eating extra steak or mixing protein powder into your smoothies, it’s important to assess what your protein requirements actually are and the best ways to get the right amount.
How Much Protein Do You Need?
Protein is the building block for most of our cells; dietary protein helps us build muscle and maintain healthy bones. It also boosts energy and helps us feel full.
According to the Dietary Reference Intakes from the USDA, most people need about 0.4 grams of protein per pound of body weight. So someone who weighs 150 pounds would need about 60 grams of protein each day. (For a more individualized estimate of how much protein you need, you can enter your height, weight, and age into the USDA’s calculator.)
Considering that one 6-ounce skinless, cooked chicken breast contains 54 grams of protein, achieving the recommended daily intake isn’t a high hurdle for most. Despite the crowded market for protein supplements and all the manufacturers touting the high protein content in their products, “most of us are already getting an adequate amount in our diet,” says Paddon-Jones.
Certain people, such as very strict vegans and those who lack access to healthy food in general, may have a harder time hitting those modest goals. (See “What Are the Best Protein Sources?” below for ideas on how to get more.)
Who Needs Extra Protein?
If you’re trying to build muscle mass or you’re a serious athlete, your daily protein needs can be up to double the average. Paddon-Jones cautions that this doesn’t really apply to someone who hits the gym a few times each week. “We’re talking about a small group of people who are working their bodies hard, every day,” he says.
Dieters also sometimes increase their protein intake in order to achieve a feeling of fullness without adding the empty calories of, say, refined carbohydrates. If you’re trying to lose weight, research suggests that aiming for 0.7 grams of daily protein for every pound you weigh might help.
If you have certain medical concerns—you’re recovering from broken bones or a severe burn, for example—your doctor may advise you to up your protein intake. The nutrient could help with regrowth and cell generation, and might speed the healing process.
What Are the Best Protein Sources?
Animal proteins are often touted as “complete proteins” because they contain all eight amino acids—which assist in healthy metabolism and body function—that your body doesn’t produce on its own. Plant-based protein sources lack some of these acids, but you can mix and match (e.g., combining brown rice and beans, or putting peanut butter on whole-grain bread) to make a complete protein.
Paddon-Jones says you shouldn’t spend too much time fretting that your protein sources are incomplete; it’s more important to eat a generally balanced diet. “If you’re getting your protein from spinach and beans, you’re getting all sorts of great nutrients that more than compensate for any lacking amino acids,” he says.
In general, shoot for a diet that includes a variety of protein sources, such as lean meat, seafood, eggs, yogurt, tofu, quinoa, nuts, and beans. These types of whole foods aren’t just good sources of protein; they’re also rich in vitamins, minerals, and other beneficial nutrients.
Federal dietary guidelines show that Americans—particularly men and teenage boys—get most of their protein from meat, poultry, and eggs. “It’s always smart to aim for a variety of nutrient sources in your diet,” says Maxine Siegel, R.D., who heads CR’s food-testing lab.
In general, avoid using protein supplements and shakes. Though protein-packed meal-replacement shakes can seem convenient, they’re often packed with unwanted sugars and other additives, and they generally lack the key nutrients you get from whole foods. And independent testing has shown that some protein products contain high amounts of arsenic, cadmium, and other dangerous heavy metals.
Can You Overdo It?
Research has shown that the body has a limited capacity to process large amounts of protein all at once. One study in the Journal of the Academy of Nutrition and Dietetics found that someone who ingests 90 grams of protein in a meal gets roughly the same benefits as someone who ingests 30 grams.
It’s better to space out your protein intake over the course of the day in order for your body to use it all effectively. Start with, say, yogurt or eggs in the morning, get some tuna for lunch, then move onto a lean meat at dinner. You can supplement throughout the day with smart protein snacks like hummus and veggies or peanut butter on crackers or sliced apples.
For most healthy adults, there isn’t a significant danger to getting more than the recommended amount of protein naturally in your diet.
“Unless you’re [genetically predisposed to] kidney issues such as advanced type 2 diabetes and kidney disease, there are few established health risks of ingesting too much protein,” says Jamie Baum, Ph.D., an associate professor of nutrition at the University of Arkansas.
Some research has shown potentially adverse effects of excess protein intake, such as straining the kidneys and the liver. But that’s generally only among people who are upping their intake with supplements. And if your protein is coming predominantly from animal sources, you could face corollary risks associated with high-meat diets, such as higher rates of coronary heart disease.
“As with so much else in diet and nutrition, the key to healthy protein intake is balance and moderation,” says Siegel.