Protein is a key part of our diets. It helps with metabolism, immunity, keeping us full and satisfied after eating, supports weight-loss, and stimulates muscle growth, Abbey Sharp, registered dietitian, previously told Fortune.
The U.S. Department of Agriculture's Dietary Guidelines for Adults recommends 10% to 35% of your daily calories come from protein sources. For a 2,000-calorie diet, that would be between 200 and 700 calories each day.
Most dietitians recommend a daily intake of 0.8 to 1.2 grams of protein per kilogram of bodyweight for adults. To get your weight in kilograms, divide your weight in pounds by 2.2. Then multiply that number by 0.8 and 1.2 to find your protein range. Someone who weighs 140 pounds should aim for 51 to 76 grams of protein per day.
Generally, people don't need to worry about how much protein they eat in a day, says registered dietitian Federica Amati. That's because as long as you are eating enough calories during the day, you are likely meeting or exceeding your protein needs, Amati says.
Protein needs vary depending on your lifestyle, age, and sex, though. Older adults need more protein. Sharp recommends they increase their daily protein intake to 1.8 grams per kilogram of bodyweight.
Your protein needs will vary mostly based on your level of activity, says Stella Volpe, president of the American College of Sports Medicine and a registered dietitian.
"It depends on the frequency, intensity, type, and the time that they spend exercising," Volpe tells Fortune.
If you're someone doing 20 to 30 minutes of exercise daily, or who goes to a Pilates class on occasion -- then you probably don't need to worry about eating more protein.
"The [recommended daily intake] of 0.8 grams [per kilogram] for most people is really just fine for their needs," Volpe says.
Heavy exercisers, though, like people training for a marathon or engaging in frequent, intense weight-lifting -- will have higher protein needs, Volpe says. They might consider increasing their daily intake as high as 1.5 grams per kilogram of body weight.
While marathon runners aren't putting on muscle the way weight-lifters are, both will have the same higher protein needs, since endurance athletes (runners, cyclists, triathletes, for example) are experiencing a high degree of muscle breakdown.
If you've just started getting serious about your workouts, you'll also want to up your protein intake, Volpe says. The more novice you are at weight-lifting or marathon training, the more muscle breakdown you'll experience, she says, so you'll need to compensate with more protein. But once you've gotten used to the workouts, you can likely stay in the range of 1.1 to 1.2 grams of protein per kilogram of body weigh, Volpe says.
Volpe also encourages periodization in your nutrition. That means during periods when you're not training as heavy, to dial back the protein so you're not taking in more than you need.
Protein isn't the only macronutrient that aids in muscle repair. Volpe say athletes should prioritize post-exercise carbohydrates -- especially in the two hours following a workout when muscle repair is crucial.
After a workout, your glycogen stores are depleted, Volpe says. Those are the body's preferred source of energy. You'll want to replenish those immediately after a workout to keep up energy levels and kickstart your recovery, she says. An ideal post-workout recovery snack is chocolate milk, says Volpe, because it's the perfect balance of carbohydrates and protein.
"Most athletes who are arguably in the fittest bodies possible, their diets are 60% carbs if not more," Sharp says. You'll want those to be complex carbohydrates, Volpe adds, consisting of foods like whole grains and sweet potatoes.
As for the people you see on social media with diets very high in protein -- who sometimes boast eating one gram of protein per pound of bodyweight -- Volpe does not advise mimicking their behavior, even if you are an intense exerciser.
"It's not necessary," Volpe says. "Most Americans take in more protein than they need anyway."
The most important thing is to make sure you have a healthy combination of carbohydrates, protein, and fat, Volpe says.
"For the most part, try to have a mixture and a variety of these macronutrients every day, and you should be good," she says. You'll also want to make sure you are eating enough calories to match your energy expenditure so you can maintain your weight, Volpe adds.