← Back to Writing How much protein do you actually need? (evidence-based ranges)
How much protein do you actually need? (evidence-based ranges)
The internet has a number. Fitness influencers have a different one. Your doctor — if they mention protein at all — has a third, usually the lowest of the three and the farthest from what the evidence actually supports.
Forty-nine randomized controlled trials, two international expert consensus statements, and the published physiology of muscle protein synthesis all point in the same direction. The specifics depend on your age. But the short version: more than you are eating.
The evidence floor: 1.6 g/kg per day
The strongest piece of evidence on protein requirements for active adults is Morton et al. (2018), a systematic review and meta-analysis published in the British Journal of Sports Medicine. It pooled data from 49 randomized controlled trials with 1,863 participants.
The finding: 1.6 g/kg of body weight per day is the point estimate for the protein intake that maximizes resistance training-induced gains in fat-free mass. The 95% confidence interval extended up to 2.2 g/kg/day — some individuals may benefit from more, but the average person doing structured resistance training gets diminishing returns above 1.6.
For a 170-pound (77 kg) person, that works out to roughly 123 grams per day. For a 200-pound (91 kg) person, roughly 146 grams per day.
This is the floor — the minimum effective dose supported by meta-analytic data, not a ceiling. Below it, you are probably leaving muscle on the table.
Most adults eat somewhere between 60 and 90 grams of protein per day. The gap between that and what the evidence supports is the single most common nutritional shortfall Protocol identifies in new members, more common than any vitamin or mineral deficit.
Why age changes the equation
The 1.6 g/kg floor was derived primarily from studies of younger adults (18-40). As you age, the rules shift, and they shift in a direction that demands more protein, not less.
The reason is anabolic resistance.
Anabolic resistance: the problem after 40
Muscle protein synthesis (MPS) is the process by which your body builds and repairs muscle tissue. In a 25-year-old, eating 20-25 grams of high-quality protein triggers a strong MPS response. The amino acids arrive, the muscle-building machinery activates, and new protein gets laid down.
In a 60-year-old eating the same 20-25 grams, the MPS response is blunted. The machinery still works, but it takes a stronger amino acid signal to activate it.
That blunted response is anabolic resistance. It develops gradually — detectable in some individuals by the mid-40s, meaningfully accelerated by the mid-50s, and clinically significant after 60. Older adults need more protein per meal and more total protein per day to get the same muscle-building stimulus that younger adults get with less.
This is why the RDA of 0.8 g/kg/day is insufficient for anyone over 40 who wants to maintain muscle mass. The RDA was set to prevent deficiency, not to optimize muscle health. The gap between “not deficient” and “actually maintaining your muscle” is large.
Protocol’s age-stratified targets
Protocol’s Muscle & Body Composition protocol (Protocol 2) sets protein targets based on age group, drawing on both the Morton et al. (2018) meta-analysis and expert consensus from PROT-AGE (Bauer et al. 2013) and the ESPEN guidelines for older adults (Cederholm et al. 2017):
Active adults under 40
| Parameter | Target |
|---|---|
| Daily protein | 1.6 - 1.8 g/kg body weight |
| Per-meal minimum | 30 g |
| Leucine per meal | 2.5 g |
Anabolic resistance is minimal at this age. The 1.6 g/kg floor is sufficient for most people. The upper end (1.8) applies during aggressive training phases or intentional body recomposition.
Active adults 40-60
| Parameter | Target |
|---|---|
| Daily protein | 1.6 - 2.0 g/kg body weight |
| Per-meal minimum | 35 g |
| Leucine per meal | 3.0 g |
Anabolic resistance is measurable in this range. The per-meal minimum rises to 35 grams because each meal needs to deliver a stronger amino acid signal to trigger the same MPS response. The daily ceiling rises to 2.0 g/kg, consistent with expert consensus (PROT-AGE, ESPEN) — though head-to-head dosing trials comparing 1.6 to 2.0 in this age group are limited.
Adults 60+ or at sarcopenia risk
| Parameter | Target |
|---|---|
| Daily protein | 1.8 - 2.0 g/kg body weight |
| Per-meal minimum | 40 g |
| Leucine per meal | 3.0 - 3.5 g |
Anabolic resistance is now significant, so the floor rises to 1.8 g/kg. The per-meal minimum is 40 grams — below that threshold, many older adults will not trigger meaningful MPS. Leucine targets increase because leucine is the amino acid most directly responsible for initiating the MPS signal, and more of it is needed to overcome the age-related blunting.
PROT-AGE recommends 1.0-1.2 g/kg for healthy older adults, rising to 1.2-1.5 g/kg for those with chronic disease and higher for acute illness. The ESPEN guidelines align closely, recommending at least 1.0-1.2 g/kg for healthy older adults. Protocol’s floor of 1.8 for this group reflects active individuals doing structured resistance training — a population underrepresented in both consensus statements.
The body weight adjustment
All of the above targets are based on actual body weight, with one exception.
If your BMI is above 30, use adjusted body weight instead of actual body weight.
At BMI 30+, a significant portion of body weight is adipose tissue, which does not have the same protein requirements as lean mass. Using actual weight overstates the target. But using ideal body weight alone tends to undershoot — adipose tissue still carries some metabolically active mass, and people with obesity have higher absolute lean mass than their ideal-weight peers.
Protocol uses adjusted body weight (typically ideal body weight plus 25-40% of the excess) or clinical judgment in these cases. For most people, this reduces the daily target by 20-40 grams compared to actual body weight — still higher than what they are eating, but a more accurate goal.
Per-meal distribution matters more than daily total
Most people track daily protein and leave it at that. But where those grams fall across the day matters just as much as how many there are.
Eating 150 grams of protein per day, split as 10g at breakfast, 30g at lunch, and 110g at dinner, does not produce the same muscle-building stimulus as splitting 150 grams across four meals at 40g, 40g, 40g, and 30g.
The mechanism goes back to MPS. Each meal is an independent opportunity to trigger muscle protein synthesis. MPS has a threshold — below a certain amount of protein (and specifically leucine), the signal does not fire. Above the threshold, MPS is active for roughly 1-3 hours before returning to baseline, regardless of how much additional protein you ate.
A banana-and-coffee breakfast wasted a synthesis opportunity. A 35-gram protein breakfast with 3 grams of leucine triggered one. Eighty grams at dinner does not make up for a 10-gram breakfast — the body does not bank protein for later. Three or four protein-sufficient meals produces more total muscle-building stimulus than two, even if the daily total is identical.
Protocol’s targets specify per-meal minimums for this reason. That number is the one that actually changes behavior.
Leucine: the trigger amino acid
Leucine is one of three branched-chain amino acids, but it has a specific role: it directly activates mTOR, the molecular pathway that initiates muscle protein synthesis. Other amino acids supply the raw material, but without sufficient leucine, the synthesis machinery does not activate.
The threshold for leucine to activate mTOR varies by age:
- Under 40: ~2.5 grams per meal
- 40-60: ~3.0 grams per meal
- 60+: ~3.0-3.5 grams per meal
Animal proteins are the most efficient leucine source. Approximate leucine content per 30 grams of protein:
| Source | Leucine per 30g protein |
|---|---|
| Whey protein | ~3.5 g |
| Eggs (5 large) | ~2.6 g |
| Chicken breast (130g) | ~2.4 g |
| Beef (120g) | ~2.4 g |
| Greek yogurt (350g) | ~2.5 g |
| Tofu (300g) | ~1.8 g |
| Lentils (350g cooked) | ~1.6 g |
Plant proteins have lower leucine density. A plant-based meal needs roughly 20-30% more total protein to deliver the same leucine signal. That is not an argument against plant protein — it just means adjusting the numbers. Protocol recommends plant-forward members either increase total protein targets by 20-30% or supplement with 2-3 grams of leucine at plant-based meals.
How to start
Start with a 3-day food log using Cronometer or MacroFactor. This step almost always reveals a gap — the average new Protocol member is eating 40-60% of their target. Knowing the baseline matters before anything else.
Then begin at 1.6 g/kg, regardless of age group. Don’t jump straight to 2.0 on day one. The gastrointestinal adjustment, the meal planning, the grocery changes — they all take time.
Focus on per-meal targets before daily totals. Hit the per-meal minimum (30g, 35g, or 40g depending on age group) at three meals. That one change typically gets daily intake to 90-120 grams — often double what you were eating before — without requiring much else to shift.
Once per-meal targets are consistent, push the daily total toward the upper end of your age-appropriate range over 2-4 weeks, provided you’re tolerating it well and training regularly.
After 2-3 weeks of detailed logging, most people develop a calibrated sense of what 35 grams of protein looks like on a plate. At that point, per-meal estimation replaces detailed tracking for most meals. The food log comes back at each coaching encounter (every 8-10 weeks) for an accuracy check.
What 35 grams actually looks like
- 4 large eggs + 1 cup Greek yogurt = ~36g protein
- 150g chicken breast = ~35g protein
- 1 scoop whey protein + 200g cottage cheese = ~38g protein
- 170g salmon fillet = ~34g protein
- 150g ground turkey + 1/2 cup black beans = ~37g protein
These are single-meal quantities. Three meals at this level gets you to 105 grams before any snacks. Add a pre-sleep protein shake (30-40g casein or casein-dominant blend) and you are at 135-145 grams — within range for most adults under 40.
The sticking point is almost always breakfast. Most people eat something carbohydrate-dominant in the morning — cereal, toast, fruit, oatmeal — and land at 5-15 grams of protein before lunch. Rebuilding breakfast around a protein anchor (eggs, Greek yogurt, a protein smoothie, last night’s leftovers) is typically where the biggest gains come from.
Creatine: the supplement that actually works
One supplement has Grade A evidence behind it: creatine monohydrate.
The International Society of Sports Nutrition position stand (Kreider et al. 2017) reviewed over 500 peer-reviewed studies and concluded creatine is the most effective ergogenic nutritional supplement for increasing high-intensity exercise capacity and lean body mass.
Protocol recommends 3-5 grams of creatine monohydrate daily for all members. No loading phase required. Expect 1-3 pounds of water weight gain in the first two weeks — that reflects intramuscular creatine saturation, not fat. It is a sign the supplement is working.
The connection to body composition
Protein targets connect directly to your body composition.
Your DEXA-measured ASMI tells you how much muscle you carry relative to your frame. Your age determines your protein target range. Whether that muscle grows, holds steady, or declines depends substantially on whether you are hitting the target.
For members in a caloric deficit (fat loss phase), protein becomes more important, not less. Eating at the ceiling of your age-appropriate range during a deficit is what preserves lean mass — you lose fat instead of muscle when protein is high enough and resistance training is consistent.
Protocol 2 coordinates all of this: DEXA establishes the baseline, protein targets are set based on the age-stratified evidence, and quarterly grip strength measurements from Protocol 4 confirm that the prescription is working. If protein compliance is above 80% and training adherence is above 80% but lean mass still declines at the 12-month rescan, the protocol escalates — hormonal assessment, sleep evaluation, metabolic screening. The number tells you something is wrong before you feel it.
For a deeper look at how these targets shift decade by decade, including specific adjustments for sarcopenia risk and hormonal changes, see The Protein Prescription by Age.
Start here
Do the 3-day food log. Track every meal in Cronometer or MacroFactor. Calculate your per-meal protein average and compare it to the target for your age group.
Most people find they are well below target. Closing that gap does not require supplements, specialty foods, or a diet overhaul. It requires rebuilding three meals a day around a protein anchor and being consistent for months, not days.
Protein does not have a compelling origin story or a celebrity endorsement. But the evidence is unusually consistent: across age groups, training levels, and study designs, adequate protein intake is the nutritional variable most tightly coupled to maintaining muscle mass, metabolic function, and physical capacity into your 60s, 70s, and beyond.
Ready to find out where you stand? Protocol’s Foundation Assessment measures what your annual physical misses — ApoB, HOMA-IR, DEXA body composition, VO2 max — and builds a specific action plan from the data.
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