How Much Protein Do You Actually Need? (By Body Weight, Goal, and Age)

Key takeaways

• The U.S. RDA of 0.8 g of protein per kg of body weight per day is the floor to prevent deficiency in sedentary adults — not the optimal target for active people.
• Active adults: 1.6–2.0 g/kg/day captures most of the muscle-building and muscle-preservation benefit. Above 2.2 g/kg/day, returns flatten.
• During fat loss, protein needs go up (1.8–2.4 g/kg of current body weight) because protein protects against muscle loss when calories are restricted.
• Older adults (65+) benefit from at least 1.2 g/kg/day to counter age-related muscle loss (sarcopenia) — substantially above the RDA.
• Distribution matters: 25–40 g of high-quality protein per meal across 3–4 meals is more effective than the same daily total back-loaded into dinner.

The single most common protein question we get is: “is the amount on the back of my whey container the right amount, or do I need more?” The honest answer almost always: probably more — but how much more depends on what you’re actually doing with your body, your age, your training, and your goal.

This article walks through the protein numbers that the evidence supports for different populations, with concrete daily targets, per-meal patterns, and real-food examples that hit them. It’s a deeper dive than the macronutrients overview or our existing Protein Power piece.

Why the RDA isn’t the right answer for most people#

The 0.8 g/kg/day Recommended Dietary Allowance (RDA) is set by the Institute of Medicine to prevent deficiency in 97.5% of healthy sedentary adults. That’s a public-health floor, not a performance target.

The protein research community has largely moved on from the RDA as an optimal recommendation. The 2016 review by Phillips, Chevalier, and Leidy — “Protein ‘requirements’ beyond the RDA” — argued explicitly that protein needs for optimal health, body composition, aging well, and recovering from illness or injury sit substantially above 0.8 g/kg/day. The American College of Sports Medicine, the International Society of Sports Nutrition, and the Academy of Nutrition and Dietetics have all published position papers recommending 1.2–2.0 g/kg/day for active adults — well above the public-health floor.

If you’re sedentary, healthy, and have no body-composition or athletic goals, the RDA is genuinely sufficient. For anyone outside that narrow category, it under-prescribes.

Targets by goal#

The goal-specific numbers that the current evidence supports:

General health and prevention#

• Sedentary adults: 0.8 g/kg/day (RDA floor)
• Lightly active adults: 1.0–1.2 g/kg/day
• Older adults (65+): at least 1.2 g/kg/day, often 1.5

The age adjustment is important. Anabolic resistance — the reduced ability of older muscle to respond to dietary protein — means older adults need more protein per meal to trigger the same muscle synthesis response. The 2014 PROT-AGE consensus statement from the European Society for Clinical Nutrition and Metabolism (ESPEN) endorses 1.0–1.2 g/kg/day for healthy older adults and up to 1.5 g/kg for those with chronic disease or sarcopenia risk.

Active adults, general fitness#

• Recreational training (3–5 hrs/week): 1.4–1.7 g/kg/day
• Serious training (5–10 hrs/week): 1.6–2.0 g/kg/day

The “1.6 g/kg” number from Morton et al.’s 2018 meta-analysis is the inflection point above which additional protein produces diminishing returns for muscle hypertrophy in resistance-trained adults. It’s a useful default ceiling for most people who aren’t in a specific cut or build phase.

Active adults, building muscle#

• Lean mass goal: 1.6–2.2 g/kg/day

Up to about 2.2 g/kg, more protein supports greater muscle mass gains during a hypertrophy program. Above that, the relationship plateaus in healthy non-elite trainees.

For a 70 kg adult: 115–155 g/day during a build.

Active adults, fat loss with muscle preservation#

• During a calorie deficit: 1.8–2.4 g/kg/day

Counterintuitively, protein needs go up during fat loss. The reason: when calories are restricted, your body looks for energy from wherever it can get it, including muscle tissue. Higher protein intake — combined with resistance training — significantly reduces muscle loss during deficit phases.

The 2018 review by Helms et al. recommends 2.3–3.1 g/kg of fat-free mass per day during a deficit. For practical purposes, 1.8–2.4 g/kg of total body weight is a reasonable simpler target for non-bodybuilder adults.

For a 70 kg adult cutting: 125–170 g/day.

Endurance athletes#

• Moderate endurance (running, cycling): 1.4–1.7 g/kg/day
• High-volume endurance (marathoners, triathletes): 1.6–2.0 g/kg/day

Endurance athletes are often under-protein-fed because the popular focus is on carbohydrate fueling. Recovery and adaptation still require adequate protein.

Pregnancy#

• Second and third trimester: RDA + ~25 g/day

The exact recommendation depends on pre-pregnancy body weight and is best discussed with an OB or registered dietitian. Most prenatal nutrition guidance in the U.S. and EU has been updating upward in recent years from older lower targets.

Recovery from illness or injury#

• Acute recovery: 1.2–2.0 g/kg/day

Protein needs rise during periods of healing — surgery recovery, infection, post-trauma. The Academy of Nutrition and Dietetics recommends elevated protein during these windows specifically because of the increased turnover of immune cells and tissue repair demands.

Why distribution across meals matters#

A daily total of 130 g of protein eaten as 50 g at dinner and three small protein servings at other meals is less effective for muscle synthesis than 130 g distributed as four 32 g servings spread across the day.

The mechanism: muscle protein synthesis (MPS) is triggered by an above-threshold dose of leucine (a branched-chain amino acid) in a single meal. The threshold is roughly 2.5–3 g of leucine, which corresponds to about 20–25 g of complete protein in younger adults and 30–40 g in older adults whose anabolic threshold is higher.

Once MPS is triggered, it takes 3–5 hours before another meal can trigger it again. So the optimal pattern is:

• 3 to 4 protein-anchored meals, each above the leucine threshold
• Spaced 4–5 hours apart

Practical translation: 25–40 g of high-quality protein per meal at breakfast, lunch, dinner, and (optionally) a smaller snack.

What “high-quality protein” means#

Not all protein sources are equally usable by your body. Quality is measured by:

• Completeness: does it contain all 9 essential amino acids in adequate amounts?
• Digestibility: how much of the protein actually gets absorbed?
• Leucine content: specifically, does a typical serving cross the leucine threshold for triggering MPS?

The most-used quality metric is the DIAAS (Digestible Indispensable Amino Acid Score). High-DIAAS sources include:

• Animal proteins: whey, milk, eggs, beef, chicken, fish — all high-DIAAS, all complete, all leucine-rich
• Plant proteins: soy is the standout (complete, well-digested); most other plant proteins are individually incomplete and lower-DIAAS, though combining them across a day works fine

For practical eating: animal sources hit the threshold in smaller servings; plant sources require larger servings or combinations to hit the same MPS trigger. Vegan athletes generally need to aim 10–20% higher in total protein to compensate for lower per-source quality and digestibility.

Real-food protein content#

For reference — typical protein per serving:

A typical 130 g/day target for a 70 kg adult could look like:

• Breakfast: 2 eggs + 1 cup Greek yogurt = 30 g
• Lunch: 100 g chicken + 1 cup quinoa = 39 g
• Dinner: 100 g salmon + 1 cup edamame = 42 g
• Snack: 1 scoop whey + a banana = 24 g
• Total: ~135 g

You can swap any meal for a plant-based equivalent — 200 g tempeh + 1 cup lentils for “lunch” gives you 37 g protein. The math works.

How to pick your number#

A simple decision tree:

1. Are you sedentary, no body composition or athletic goals? → 0.8–1.0 g/kg/day. The RDA is enough.
2. Are you active and trying to maintain weight? → 1.4–1.7 g/kg/day.
3. Are you in a calorie deficit trying to lose fat? → 1.8–2.4 g/kg/day. Protein protects muscle when calories are scarce.
4. Are you trying to build muscle? → 1.6–2.2 g/kg/day. Higher within the range during your build phase.
5. Are you 65+? → At least 1.2 g/kg/day, regardless of activity. Distribute across meals — older muscle needs above-threshold doses to respond.
6. Are you pregnant, recovering from illness, or post-injury? → Talk to a clinician for goal-specific guidance.

For most adults reading this, the answer falls in the 1.6–2.0 g/kg band. Pick a number, hit it consistently for two weeks, see how your body responds, adjust if needed.

What if hitting the target feels like too much food?#

Common complaint when people start tracking protein: “I can’t eat that much.” A few practical fixes:

• Anchor with high-protein-density foods. Greek yogurt, cottage cheese, eggs, lean fish, chicken breast, tofu, tempeh, whey. Adding 100 g of chicken breast to a meal contributes 31 g of protein for 165 calories — that’s high return.
• Use whey or another high-quality protein supplement. A scoop of whey is 24 g of protein for 100–120 calories. Two scoops a day closes most adults’ protein gap without forcing extra calories.
• Front-load breakfast. Most people’s protein deficit is at breakfast (toast and fruit doesn’t get you to 25 g). Three eggs + Greek yogurt + a slice of cheese is 35 g of protein for ~400 calories.
• Add legumes to lunch. A bowl of lentil soup or a chickpea- based salad adds 15–20 g of protein and a lot of fiber for 200–300 calories.

If you’ve tried these and still can’t hit the target without overshooting calories, your target may be too high for your body size and goals. Pick the lower end of the recommended range.

What if I’m worried about kidney health?#

One persistent concern: does high protein damage the kidneys? In healthy adults, the answer is no — multiple meta-analyses have found no association between high protein intake (up to 2.5 g/kg/day) and kidney disease in healthy people.

The exception that’s important: people with pre-existing chronic kidney disease (CKD) are advised to limit protein to slow disease progression. If you have CKD, eGFR concerns, or have been told by a doctor to limit protein, this whole article doesn’t apply to you — work with your clinician.

For everyone else with healthy kidney function: high protein is well- tolerated. Drink enough water and don’t worry about it.

Frequently asked questions#

Where to go next#

• Macronutrients Explained — the broader framework
• Protein Power — practical high-protein eating
• Calorie Tracking vs. Macro Tracking — when adding the protein column pays off
• Pre-Workout Fuel — protein around training
• Recovery Day Eating — protein after training

Sources#

1. Phillips SM, Chevalier S, Leidy HJ. Protein “requirements” beyond the RDA: implications for optimizing health. Applied Physiology, Nutrition, and Metabolism, 2016. PubMed
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. British Journal of Sports Medicine, 2018. PubMed
3. Helms ER, Aragon AA, Fitschen PJ. Evidence-based recommendations for natural bodybuilding contest preparation: nutrition and supplementation. Journal of the International Society of Sports Nutrition, 2014. PubMed
4. Bauer J, Biolo G, Cederholm T, et al. Evidence-Based Recommendations for Optimal Dietary Protein Intake in Older People: A Position Paper From the PROT-AGE Study Group. JAMDA, 2013. PubMed
5. Devries MC, Sithamparapillai A, Brimble KS, et al. Changes in Kidney Function Do Not Differ between Healthy Adults Consuming Higher- Compared with Lower- or Normal-Protein Diets: A Systematic Review and Meta-Analysis. Journal of Nutrition, 2018. PubMed
6. Wolfe RR. The role of dietary protein in optimizing muscle mass, function and health outcomes in older individuals. British Journal of Nutrition, 2012. PubMed