How Much Protein Do You Actually Need?

Few nutrition topics generate more confusion than protein. The official recommendation hasn’t changed since 1989. Social media is filled with conflicting claims. And the actual research literature has moved significantly since that original RDA was set.

Here’s what the evidence shows about protein requirements for different goals and populations.

What the RDA actually represents

The RDA of 0.8 grams of protein per kilogram of body weight was established to prevent protein deficiency in sedentary adults, not to optimize muscle mass, metabolic health, or longevity. A 150-pound (68 kg) adult at 0.8 g/kg would consume about 54 grams of protein per day.

This is a floor, not a target. The research consistently finds that higher intakes than the RDA produce better outcomes for muscle preservation, body composition during weight loss, satiety, and metabolic rate in people with health goals beyond simply avoiding deficiency.

Protein for body composition and weight loss

During a calorie deficit, the body draws energy from both fat and lean mass (muscle). Adequate protein intake and resistance training are the primary tools to shift that ratio toward fat loss while preserving muscle.

A 2016 systematic review in the American Journal of Clinical Nutrition analyzing 36 studies found that protein intakes above the RDA, specifically in the range of 1.2–1.6 g/kg, were associated with significantly greater fat loss and lean mass preservation during calorie restriction compared to RDA-level intake.

Higher protein intake during weight loss also improves satiety. Protein is the most satiating macronutrient, producing greater reductions in hunger hormones (particularly ghrelin) and greater increases in satiety hormones (GLP-1, PYY) compared to equivalent calories from carbohydrates or fat.

For people eating at very low calorie levels, which includes many GLP-1 medication users eating 1,000–1,200 calories per day, prioritizing protein within that calorie budget is particularly important because the lean mass loss risk is higher.

Protein for muscle building

The research on protein and muscle hypertrophy (growth) is extensive. For healthy adults engaged in resistance training, the consensus from meta-analyses is that protein intakes of approximately 1.6 g/kg maximize muscle protein synthesis, with diminishing returns above that level.

A 2018 meta-analysis in the British Journal of Sports Medicine analyzed 49 studies covering 1,800 participants and found that protein supplementation above habitual intake significantly increased muscle mass and strength gains from resistance training. The benefits plateaued at roughly 1.62 g/kg, with no additional muscle gain above that threshold.

This analysis has driven the common recommendation you see in sports nutrition contexts of “1 gram per pound of body weight,” which translates to approximately 2.2 g/kg. That target is intentionally above the plateau to ensure most people reach it even with day-to-day variation.

Protein for older adults

Protein needs increase with age because muscle protein synthesis becomes less efficient in older adults, a phenomenon called anabolic resistance. The same protein stimulus that produces robust muscle protein synthesis in a 30-year-old produces a smaller response in a 65-year-old.

Research supports higher protein intake for adults over 60: typically 1.2–1.6 g/kg minimum for those doing moderate activity, with some evidence for benefit up to 2 g/kg in older adults specifically trying to preserve muscle and strength.

A 2016 consensus statement from the PROT-AGE study group, a panel of researchers specializing in aging and nutrition, recommended a minimum of 1.0–1.2 g/kg for healthy older adults and 1.2–1.5 g/kg for those with acute or chronic illness. They noted that evenly distributing protein across meals was particularly important in older adults because of greater anabolic resistance.

Protein distribution across meals

The body doesn’t store excess amino acids the way it stores fat or glycogen. Amino acids consumed beyond what’s immediately needed for protein synthesis or other functions are oxidized (burned for energy) or excreted. This has practical implications for how you distribute protein across the day.

Most research suggests a per-meal threshold of around 30–40 grams of high-quality protein (containing approximately 2.5–3 grams of leucine, the amino acid that most potently triggers muscle protein synthesis) produces near-maximal muscle protein synthesis in a single meal. Eating 150 grams of protein in one sitting doesn’t produce triple the muscle-building signal of 50 grams.

Distributing protein intake relatively evenly across three or four meals, each containing 30–40 grams of high-quality protein, produces a more sustained anabolic stimulus throughout the day compared to eating the same total protein concentrated in one or two large meals. This is particularly relevant for older adults and anyone specifically trying to build or preserve muscle.

Protein quality: essential amino acids and leucine

Not all proteins are equal in their ability to stimulate muscle protein synthesis. The key variables are essential amino acid content (amino acids the body cannot synthesize and must obtain from food) and leucine content specifically.

Animal proteins (meat, fish, dairy, eggs) are complete proteins, meaning they contain all essential amino acids in roughly the proportions needed for human physiology. Plant proteins are often lower in specific essential amino acids (soy is an exception and is considered complete).

Leucine is the primary trigger for muscle protein synthesis, and it’s found in higher concentrations in animal proteins and certain plant proteins like soy. Meeting protein targets from plant sources is achievable but typically requires higher total protein intake and/or strategic combination of sources to ensure adequate essential amino acid delivery.

If you’re eating primarily or exclusively plant-based, targeting the higher end of the recommended range (1.6 g/kg rather than 1.2 g/kg) helps buffer for lower amino acid bioavailability.

Is high protein safe?

For healthy adults with normal kidney function, protein intakes well above the RDA are consistently safe. High protein intake does not cause kidney disease in people with healthy kidneys. The concern about protein and kidneys applies to people with pre-existing chronic kidney disease, where reduced protein intake is often recommended to slow disease progression.

A 2016 review in Advances in Nutrition concluded that protein intakes up to at least 2.5 g/kg are safe for healthy adults, with no evidence of adverse effects on kidney function, bone health, or liver function at these levels.

Very high protein intake (above 3 g/kg) in the context of an overall calorie excess can contribute to fat gain. This is not a protein-specific effect; excess calories from any source can be stored as fat.

Practical targets by goal

Goal	Recommended intake
General health, sedentary	1.0–1.2 g/kg
Weight loss, preserving muscle	1.2–1.6 g/kg
Building muscle, resistance training	1.6–2.2 g/kg
Adults over 60, active	1.2–1.6 g/kg
Very low calorie diet (GLP-1 users)	1.2–1.6 g/kg (supplement if needed)

The bottom line

The RDA of 0.8 g/kg is a floor for avoiding deficiency, not a target for optimal health. For most adults with body composition or fitness goals, 1.2–1.6 g/kg is the evidence-based starting point, and those doing resistance training or over 60 can benefit from approaching the higher end of that range or above.

Spreading protein across meals matters almost as much as total intake, and ensuring adequate leucine content, either from animal proteins or strategic plant protein combinations, determines how effectively that protein translates into muscle synthesis.