Athletiqa · Nutrition · Week of August 9, 2026 · 8 min read

Protein might be the most argued-about number in fitness. Depending on who you follow, you need 0.8 grams per kilogram of body weight, or 1 gram per pound, or as much as you can physically eat. The good news: this is one of the best-studied questions in sports nutrition, and the evidence converges on a surprisingly clear answer.

Here it is up front: if you train and want to build or keep muscle, aim for roughly 1.6 grams of protein per kilogram of body weight per day, anywhere in a band of about 1.4–2.2 g/kg. For an 80 kg (176 lb) person, that's about 115–175 g of protein a day, with 130 g being a well-supported target. Everything else (timing, distribution, the post-workout shake) matters far less than hitting that daily total.

Now let's look at where those numbers come from, and how confident you should be in them.

The most influential piece of evidence is a 2018 meta-analysis in the British Journal of Sports Medicine by Robert Morton and colleagues [1]. A meta-analysis pools many individual studies into one statistical answer: in this case 49 randomized controlled trials with 1,863 participants, all combining resistance training with different protein intakes.

Three findings stand out:

Other syntheses agree. A 2020 dose-response meta-analysis in Nutrition Reviews found lean mass rising with each additional 0.1 g/kg of daily protein up to a similar zone [2], and a 2022 meta-analysis of 74 trials in the Journal of Cachexia, Sarcopenia and Muscle confirmed that adding protein above habitual intakes reliably improves lean mass in both younger and older adults [3]. The International Society of Sports Nutrition's position stand recommends 1.4–2.0 g/kg/day for exercising individuals, squarely in line with the meta-analytic picture [4].

Evidence check: multiple independent meta-analyses of RCTs pointing the same way. This is strong evidence, about as good as sports nutrition gets.

The official Recommended Dietary Allowance is 0.8 g/kg/day. That number was designed to prevent deficiency in the general population, not to optimize muscle, strength, or recovery in people who train. For training populations, the trial evidence consistently shows better results at roughly double the RDA [1,3,4]. Both things can be true: 0.8 g/kg keeps you out of deficiency; 1.6 g/kg supports adaptation.

You've probably heard that the body "can only absorb" 20–30 g of protein per meal and the rest is wasted. This idea came from short-duration studies measuring muscle protein synthesis for a few hours after a meal.

A 2023 trial in Cell Reports Medicine tested it directly [5]. Researchers gave participants 25 g or 100 g of protein after a workout and tracked the response for 12 hours, much longer than earlier studies. The 100 g dose produced a greater and much more prolonged anabolic (muscle-building) response, with no sign of a ceiling. Protein digestion simply slows down to match the dose; little is "wasted."

One well-conducted trial is not final proof of every detail, but as a refutation of a hard per-meal limit the finding is decisive and consistent with digestion physiology. Practical translation: if you eat two or three large protein feedings instead of five small ones, you are not sabotaging your gains. Eat your protein in whatever pattern you can actually sustain.

A little, with the emphasis on little. Reviews of protein distribution research find that spreading protein evenly across meals produces, at best, small advantages that are hard to detect once total daily protein is matched [6]. The classic "anabolic window" (the idea that you must consume protein within 30–60 minutes of training) has similarly shrunk under scrutiny: the window looks more like a barn door spanning several hours, and total daily intake dominates the outcome [4,6].

A reasonable, low-effort default supported by the distribution literature: include a meaningful protein dose ( 0.4 g/kg, e.g., 25–40 g) in each of 3–4 daily meals. Just know this is an optimization at the margins, not a requirement.

Evidence check: strong evidence that total intake dominates; moderate evidence that distribution adds any measurable benefit at all.

The most persistent worry is kidney damage. For healthy people, the trial evidence is reassuring. A 2026 meta-analysis of 22 randomized trials in Diabetes, Obesity and Metabolism compared high-protein diets (≥2 g/kg/day or 25–35% of calories) against normal or lower intakes and found no biochemical evidence of kidney injury: no adverse creatinine changes, and a small rise in filtration rate consistent with the kidneys' normal workload adjustment rather than damage [7]. This echoes earlier systematic reviews reaching the same conclusion.

Two honest caveats. First, most trials run months, not decades. Truly long-term data is limited, so we label lifetime safety at very high intakes as an open question rather than settled. Second, and importantly: this applies to healthy kidneys. If you have kidney disease or reduced kidney function, protein targets are a conversation with your physician or a registered dietitian, not a fitness article.

The protein question is a rare piece of good news in nutrition science: the evidence is deep, consistent, and practical. Hit your number, train hard, and spend your worrying elsewhere.

This article is educational and not medical advice. If you have kidney disease, another medical condition, or take medication affecting kidney function, consult a qualified professional before changing your protein intake.