Even if it’s not your personal goal to swell to the size of a rugby flank, you need protein for many reasons. The macronutrient basically keeps your body running. Protein contains the building blocks of many vital bodily functions, including muscle synthesis, hormone production, nutrient transport, and immune system support. So, how much should you really be getting?
These days, it feels like protein recommendations are all over the place. The number you were taught in Life Orientation seems laughably low, but the number your favourite fitness TikToker is preaching online seems near impossible to achieve. The old rule of thumb was 2.2 grams per kilogram of target bodyweight. Now, we’ve seen recommendations as high as 3.9 grams per kilogram. (For a guy aiming to weigh 85kg, that’s roughly 330 grams of protein daily—or nearly ten 180g steaks.) What’s the truth?
We asked the world’s smartest protein experts to find the answer.
MEET THE EXPERTS: Donald Layman, Ph.D., is a retired University of Illinois food science and human nutrition professor with decades of work in protein research, and a fellow at the American Society of Nutrition. Layne Norton, Ph.D, is a nutrition expert and professional bodybuilder. And then there’s Leslie Bonci, R.D., sports dietitian for the Kansas City Chiefs.
Luckily, it’s not all that complicated.
How Much Protein Do You Actually Need?
There’s certainly a low end—a very low end.
According to the World Health Organization (WHO) and similar guidance followed by the South African Department of Health, adults require a minimum of 0.8 grams of protein per kilogram of bodyweight per day. For reference, that’s only about 65 grams for an average 80kg man.
READ MORE: 3 No-Cook High-Protein Meals for When You’re Too Busy to Cook
What’s interesting: This recommendation came from a study done decades ago on healthy, active young men, and was based on staying in nitrogen balance—essentially the minimum required to avoid losing muscle. But this baseline doesn’t reflect the needs of people who train regularly or are trying to build strength.
“It’s a legitimate, but extremely low-end, number,” says Layman. “People use it as their maximum requirement, and it’s not. That’s the absolute minimum that researchers think you’d be safe at.”
How Much Protein Do You Need to Build Muscle?
The answer depends a lot on your age, your training intensity, and your goals, says Bonci. In general, aim for 1.3 to 2.2 grams of protein per kilogram of bodyweight—closer to the upper end if you’re over 60 (to prevent age-related muscle loss called sarcopenia) or if you’re strength training regularly.
To simplify things:
“If you’re eating 2.2 grams per kilogram of body weight, you’re getting 95 plus percent of the protein’s benefits,” says Norton.
“For most people who aren’t trying to compete in bodybuilding, any more than that probably doesn’t make a big difference,” he adds. “You could go up to 3.3 grams per kilogram and still see some marginal gains. Beyond that, you’re unlikely to notice a difference.” (Of course, all that steak and chicken won’t help if you’re not lifting weights.)
READ MORE: 11 High-Protein Foods That Do More Than Just Build Muscle
There’s also no solid evidence that high-protein diets are dangerous. If anything, they might help you meet your nutritional needs more efficiently.
“Natural protein-rich foods have the highest nutrient density of any food group,” says Layman. “If you hit your protein goals, especially using animal proteins, you’ll likely cover around 65 percent of your vitamin and mineral needs with just 40 percent of your calorie intake.”
What If You’re Plant-Based?
You may need to aim even higher if you’re on a plant-based diet. Plant proteins tend to be lower in quality and bioavailability—meaning your body doesn’t absorb and use them as efficiently. If you’re vegan, vegetarian, or just eating more plant-based meals, Layman suggests increasing your target by 30 to 40 percent.
READ MORE: 8 Best Foods for Faster Muscle Recovery, Backed by Science
You might’ve heard about using lean body mass instead of total bodyweight for these calculations. While that can be helpful—especially for those carrying extra weight—it’s not essential. Most people don’t have access to accurate body composition testing, and using target weight works just as well if you’re aiming for fat loss or muscle gain.
The Bottom Line
If you’re getting about 2.2 grams of protein per kilogram of bodyweight per day, you’re likely covering all your bases for health, recovery, and muscle growth. If you’re pushing hard in the gym or getting older, edging higher won’t hurt.
This article was originally published on Men’s Health US
