Protein: How Much Do You Actually Need?
The RDA for protein is 0.8g per kilogram of bodyweight. That number represents the minimum to prevent deficiency in sedentary adults.
For anyone who trains — and for most people over 40 — research suggests that number falls short for optimizing body composition, recovery, and muscle maintenance. Here's what the evidence actually supports.
What the Research-Backed Literature Shows
For people who resistance train, sports nutrition research consistently supports higher intakes. Commonly cited targets in the literature fall in the range of 1.6–2.2g per kilogram of bodyweight (roughly 0.7–1g per pound) for maximizing muscle protein synthesis, supporting recovery, and maintaining or building lean mass.
Higher intakes — up to 3g/kg — appear safe in the research and may offer benefits during caloric restriction (preserving muscle while losing fat), though returns appear to diminish above 2.2g/kg for most people.
As a rough reference point discussed in sports nutrition literature: approximately 1g per pound of lean bodyweight is a commonly used practical target for people engaged in regular resistance training — though individual needs vary.
Why Protein Matters More As You Age
After 40, research shows that the muscle protein synthesis response to a given dose of amino acids becomes less efficient — a phenomenon called anabolic resistance. More protein stimulus is needed to generate the same muscle-building signal.
This is one of the strongest arguments in the research for prioritizing protein as you age, not less. The combination of adequate protein, resistance training, and sufficient sleep directly counteracts the age-related muscle loss (sarcopenia) that accelerates after 40.
Distribution Matters
It's not just total daily protein — research supports distributing protein across multiple meals to maximize how effectively the body uses it. Studies suggest spreading protein across 3–4 meals, with substantial amounts per meal, is more effective than concentrating most protein in one sitting, even if daily totals look the same on paper.
Practical Sources
You don't need protein shakes to hit research-supported targets — but they're a practical option if whole food intake falls short.
Whole-food sources with high protein density include: eggs, chicken breast, Greek yogurt, cottage cheese, lean beef, fish (particularly salmon and tuna), and legumes (lower bioavailability but useful as part of a varied diet).
Protein shakes are a tool, not a foundation. The research generally supports getting the majority from whole food sources.
The Bottom Line
The evidence supports substantially more than the 0.8g/kg RDA for active individuals, particularly those over 40. The exact target worth discussing with a healthcare provider or registered dietitian based on your goals and overall health picture.
What does your current protein intake actually look like? Most people are surprised when they track it for the first time.
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Sources
1. Institute of Medicine. "Dietary Reference Intakes for Energy, Carbohydrate, Fiber, Fat, Fatty Acids, Cholesterol, Protein, and Amino Acids." National Academies Press. 2005. (RDA of 0.8g/kg as minimum for sedentary adults)
2. Morton RW, Murphy KT, McKellar SR, et al. "A systematic review, meta-analysis and meta-regression of the effect of protein supplementation on resistance training-induced gains in muscle mass and strength in healthy adults." British Journal of Sports Medicine. 2018;52(6):376–384. (1.6–2.2g/kg target for trained individuals)
3. Antonio J, Ellerbroek A, Silver T, et al. "A high protein diet (3.4 g/kg/d) combined with a heavy resistance training program improves body composition in healthy trained men and women." Journal of the International Society of Sports Nutrition. 2015;12:39. (safety of higher intakes up to 3g/kg)
4. Wall BT, Gorissen SH, Pennings B, et al. "Aging is accompanied by a blunted muscle protein synthetic response to protein ingestion." PLOS ONE. 2015;10(11):e0140903. (anabolic resistance in older adults)
5. Areta JL, Burke LM, Ross ML, et al. "Timing and distribution of protein ingestion during prolonged recovery from resistance exercise alters myofibrillar protein synthesis." Journal of Physiology. 2013;591(9):2319–2331. (protein distribution across meals)
— Dr. Scott