How Much Protein Do Lifters Actually Need? What the Evidence Says

Walk into any gym and ask how much protein you need, and you’ll get answers from “whatever, bro” to “a gram per pound or you’re wasting your time.” Some guys are choking down shakes like it’s their job. Others barely think about it.

So let’s skip the gym lore and look at the actual research. There are two pieces worth knowing about: a big meta-analysis that pooled dozens of trials, and a position stand from a major sports nutrition society. They line up pretty well.

The meta-analysis: 49 trials, 1,863 people

In 2018, a team led by Robert Morton published a systematic review and meta-analysis in the British Journal of Sports Medicine. They pulled together 49 randomized controlled trials with 1,863 participants, all looking at whether adding protein to a resistance-training program of at least six weeks improves results.¹

A meta-analysis like this sits near the top of the evidence pile. Instead of one small study, you get the combined weight of dozens.

What they found

Protein supplementation significantly increased training gains compared with training alone:¹

Measure	Extra gain with protein (average)
One-rep max strength	+2.49 kg
Fat-free mass	+0.30 kg
Muscle fibre cross-sectional area	+310 µm²

Read that table carefully. The effects were real, but they were modest. An extra 2.5 kg on your max over the course of a study, and an extra 0.3 kg of fat-free mass. Protein helps. It doesn’t replace the training. The lifting does most of the work.

The plateau

The most useful finding: the benefit levelled off. Protein intakes beyond about 1.62 g per kilogram of body weight per day produced no further gains in fat-free mass.¹ The authors summarized it as intakes above roughly 1.6 g/kg/day not contributing further gains.

That’s about 130 g a day for an 80 kg (176 lb) person. A lot less than the “one gram per pound” crowd preaches.

Who benefited more (and less)

• Experienced lifters got more out of extra protein than beginners.¹
• Older people got less of a boost from supplementation as age increased.¹ The authors noted that older participants in the studies tended to start with lower protein intakes and received smaller doses, and they suggested older people may need more protein to get the same effect.¹

The position stand: 1.4 to 2.0 g/kg

The International Society of Sports Nutrition’s 2017 position stand on protein reviewed the wider literature and landed here:²

• 1.4–2.0 g/kg/day is sufficient for most exercising people to build and maintain muscle.
• Higher intakes (2.3–3.1 g/kg/day) may help resistance-trained people hang on to lean mass while dieting.
• Per meal, aim for about 0.25 g/kg or 20–40 g of high-quality protein, spread every 3–4 hours.
• Whole foods with all the essential amino acids are a solid base. Supplements are a convenience, not a requirement.
• Concerns that intakes in this range are unhealthy are, in their words, unfounded in healthy, exercising individuals.

Note that last qualifier. If you have kidney disease or another medical condition, your protein needs are a conversation for your doctor, not a gym forum.

Putting them together

The two sources fit. The ISSN’s range of 1.4–2.0 g/kg brackets the meta-analysis plateau of about 1.6 g/kg. So a practical, evidence-based target for most lifters is:

Around 1.6 g of protein per kg of body weight per day, spread across two to four meals of 20–40 g or more.

Going higher isn’t dangerous for healthy people, per the ISSN, and may help during a diet. It just isn’t likely to add more muscle on its own.

What this means on a carnivore diet

Here’s where meat-eaters can relax. Every one of these studies was about adding protein, mostly via supplements, to normal diets. On a carnivore diet, protein is the main event. If you’re eating two or three substantial meat-based meals a day, you’re very likely already in the range.

A few things to watch:

• Distribution. One huge meal a day might cover your total but miss the “spread it out” advice. If you’re training hard and recovering poorly, try two or three meals.
• Don’t swing too lean. Hitting a protein target with very lean meat and little fat can leave you short on total energy. The fattier cuts carry the calories.
• These studies weren’t on carnivore diets. The participants ate mixed diets with protein added on top. We’re applying the findings, not quoting a carnivore trial. That’s the honest version.

Limits of the evidence

The meta-analysis is strong evidence, but it isn’t the final word. The individual trials varied in length, training programs, protein types and populations. The gains are averages; your results will vary. And as with most nutrition research, the studies ran for weeks to months, not years. That’s why I’d call this evidence moderate: consistent and well-pooled, but with limits.

The bottom line

Protein matters, but less dramatically than the supplement aisle suggests. Around 1.6 g/kg/day, spread across the day, covers it for most lifters. More won’t hurt a healthy person but probably won’t build extra muscle on its own. And if you’re eating meat at every meal, you’re probably already there.

Now stop worrying about the shake and go hit your squats.