How Much Protein Do You Really Need? (Backed by 3 Studies)

The government-recommended protein intake, 0.8 grams per kilogram of body weight, is enough to survive. It's not enough to build muscle, preserve muscle in a calorie deficit, or feel full on a diet.

The actual evidence-backed target is roughly double that number. This has been the consensus among sports scientists and dietitians for over a decade.

Here's what three landmark studies say about how much protein you really need, exactly how to hit that number without turning every meal into a chicken breast, and why the "too much protein damages your kidneys" myth is completely wrong for healthy adults.

The RDA of 0.8 g/kg: What It Actually Means

The Recommended Dietary Allowance (RDA) of 0.8 grams of protein per kilogram of body weight is a minimum. It's designed to prevent deficiency in a sedentary adult. Not to optimize anything.

• 0.8 g/kg means a 70 kg (155 lb) adult needs 56g of protein per day to avoid protein deficiency.
• The RDA does not account for muscle preservation, exercise, aging, weight loss, or performance goals.
• The number was set in 1968 based on nitrogen-balance studies in inactive adults. It hasn't been meaningfully updated since. The science on protein needs has moved on.

If you lift, train, cut calories, or want to preserve muscle as you age, the RDA is not your target. It's a floor, not a ceiling.

Study 1: The 1.6 g/kg Plateau (Morton et al. 2018)

The paper: "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.

What they did: Pooled 49 studies with 1,863 total participants performing resistance training. Analyzed how each group's protein intake related to their muscle gain over the training period.

What they found: Muscle gain kept increasing as daily protein rose, up to about 1.6 g/kg of body weight per day. Above 1.6 g/kg, extra protein produced no additional muscle gain.

Translated to real numbers:

• 60 kg (132 lb) lifter → 96g protein/day
• 70 kg (155 lb) lifter → 112g protein/day
• 80 kg (176 lb) lifter → 128g protein/day
• 90 kg (200 lb) lifter → 144g protein/day

The nuance: The "no benefit above 1.6" ceiling applies to average lifters in normal training. Athletes in extreme cuts or intense training blocks often need more, which is exactly what study #2 shows.

Study 2: More Protein in a Cut = More Muscle Saved (Longland et al. 2016)

The paper: "Higher compared with lower dietary protein during an energy deficit combined with intense exercise promotes greater lean mass gain and fat mass loss." American Journal of Clinical Nutrition, 2016.

What they did: Put 40 young men in a steep 40% calorie deficit for 4 weeks. Both groups did intense exercise 6 days per week. One group ate 1.2 g/kg of protein. The other ate 2.4 g/kg.

What they found:

Group	Fat lost	Lean mass gained
Low protein (1.2 g/kg)	3.5 kg	0.1 kg
High protein (2.4 g/kg)	4.8 kg	1.2 kg

The high-protein group lost more fat AND gained muscle, even in a 40% calorie deficit. That's genuinely unusual and only happened because protein was cranked up.

The takeaway: When you cut calories, your protein needs go up, not down. Aim for 2.0–2.4 g/kg during a cut. This is the single most important nutrition lever for anyone trying to lose weight without losing muscle.

Study 3: The ISSN Position Stand (Jäger et al. 2017)

The paper: "International Society of Sports Nutrition Position Stand: Protein and Exercise." Journal of the International Society of Sports Nutrition, 2017. Co-authored and signed by 12 leading protein researchers, including Stuart Phillips and Jose Antonio.

Key recommendations from the position stand:

• Athletes: 1.4–2.0 g/kg/day for anyone who exercises regularly
• Distribution: 20–40g of high-quality protein per meal, spaced every 3–4 hours
• Timing: Pre-sleep protein (30–40g of casein) reduces overnight muscle protein breakdown
• Plant-based diets: Slightly higher total intake (10–20% more) due to lower digestibility of plant proteins

This is the "official" recommendation for anyone who trains. If you want a single citation for what the science says about protein intake for lifters, this is it.

Your Daily Protein Target by Goal

Here's the practical table combining all three studies. Find your row:

Your situation	Target (g/kg)	60 kg (132 lb)	70 kg (155 lb)	80 kg (176 lb)
Sedentary, no fitness goals	0.8	48g	56g	64g
Recreational exercise, general health	1.2–1.6	72–96g	84–112g	96–128g
Resistance training, maintenance	1.6–2.0	96–120g	112–140g	128–160g
Cutting (calorie deficit)	2.0–2.4	120–144g	140–168g	160–192g
Older adult (60+) preserving muscle	1.2–1.6	72–96g	84–112g	96–128g
Athlete in intense training	1.8–2.2	108–132g	126–154g	144–176g

If you'd rather have your exact number calculated for you, our free protein calculator takes 30 seconds and factors in your weight, activity level, and goal.

How to Actually Hit 120–150g of Protein Per Day

Most people fail here, not because they don't know the target, but because they don't know how to reach it consistently.

Protein Amounts to Memorize (per 100g)

Once you know these numbers, you'll never guess again:

• Chicken breast (cooked): 31g protein
• Salmon: 22g protein
• Greek yogurt (0% fat): 10g protein
• Cottage cheese (2%): 13g protein
• Whey protein: ~24g per 30g scoop
• Eggs: 6g per large egg
• Tuna (canned in water): 25g
• Tofu (firm): 8g
• Lentils (cooked): 9g
• Almonds: 21g per 100g (but calorie-dense at 580 cal per 100g)

The 30/30/30/30 Rule

Eat 30g of protein at each of three meals and 30g spread across snacks. That gives you 120g/day, enough for anyone under 75 kg to hit their target.

If you're 80+ kg or cutting, bump each meal to 35–40g.

Sample Day Hitting 145g on 2,000 Calories

Meal	Foods	Protein
Breakfast	3 eggs + 200g Greek yogurt + 40g oats	38g
Lunch	150g grilled chicken + 100g rice + veg	55g
Snack	30g whey + 1 apple	25g
Dinner	150g salmon + sweet potato + broccoli	35g
Total		~153g

This isn't extreme. It's a normal day of eating if you're intentional about protein at each meal.

The "Too Much Protein" Question: Settled

If you've heard that high-protein diets damage your kidneys or liver, the research on this is unambiguous.

Antonio et al. 2015 & 2016 (Journal of Nutrition and Metabolism, and Journal of the International Society of Sports Nutrition) followed resistance-trained men eating 3.4 g/kg (over twice the RDA) for one full year. Result: zero changes in kidney function, liver function, blood lipids, or any measured health marker.

Multiple systematic reviews since have replicated this finding. High-protein diets are safe for healthy adults, even at 2–3x the recommended amounts, over extended periods.

The kidney concern applies only to people who already have chronic kidney disease. If your kidneys are healthy, higher protein doesn't damage them. Full stop.

Timing and Distribution: Why Per-Meal Protein Matters

More important than "did I hit my total daily protein" is "did I hit an effective dose at each meal."

Muscle protein synthesis (MPS), the biological process that actually builds muscle, is triggered by roughly 25–40g of protein per meal in most adults. Below that, MPS is suboptimal. Above it, the extra protein just gets metabolized.

• Eating 100g of protein in one sitting doesn't build more muscle than eating 30g in that same sitting.
• Eating 10g of protein every two hours doesn't build as much muscle as four meals of 30g.

The rule: aim for at least 25–30g of high-quality protein per meal, spread across 3–5 meals per day. Older adults may need slightly more per meal (30–40g) because MPS becomes less sensitive with age.

Pre-sleep protein: The ISSN paper recommends 30–40g of casein (or Greek yogurt or cottage cheese, which are casein-dominant) before sleep. During the 7–9 hour overnight fast, this slow-digesting protein reduces muscle breakdown. If you're serious about building muscle, this is a small optimization worth doing.

Plant-Based Protein: The Two Adjustments

Plant proteins are slightly less bioavailable than animal proteins (roughly 15–20% less absorbed on average). Two ways to compensate:

1. Bump your total intake by ~20%. A 70 kg vegetarian aiming for 1.6 g/kg (112g) should target closer to 135g of plant protein.

2. Combine sources at each meal. Individual plant proteins are usually missing one or two essential amino acids. Combining sources gives you a complete amino acid profile:

• Rice + beans/lentils
• Pita + hummus
• Tofu + quinoa
• Peanut butter + wholemeal bread
• Nuts + seeds

Plant-based lifters build muscle at the same rate as omnivores in controlled studies. Hitting the number just requires more intentional planning.

Frequently Asked Questions

Is 100g of protein enough per day?

For a sedentary 100 kg (220 lb) adult, yes. For anyone who lifts or exercises regularly, 100g is likely below your target. Most active adults need 120–160g. Check the table above with your bodyweight and goal.

Can I eat too much protein in one meal?

Not in any harmful sense. Excess protein isn't stored as protein. It's metabolized for energy or converted to glucose. But eating 100g of protein in one meal doesn't build more muscle than 30–40g in that meal. It's a diminishing-returns curve.

Do I need protein powder?

No. Protein powder is convenient, not necessary. Anyone can hit 150g/day from whole foods with intentional meal planning. Whey is useful because it's cheap, fast to consume, and doesn't require cooking. But it's not superior to chicken or eggs for muscle building.

Is high-protein bad for weight loss?

The opposite. High protein is the single most important nutrition variable for losing fat while preserving muscle. Longland 2016 (above) is one of many studies showing this.

Does protein cause weight gain?

Only if you're in a calorie surplus. Protein has 4 calories per gram, the same as carbs. What matters is total calorie intake. Protein actually has the highest thermic effect of food (TEF), so about 25–30% of the calories from protein are burned just digesting it. That's the highest of any macronutrient.

How much protein for older adults?

Adults over 60 need more per meal, not necessarily more per day. Because muscle protein synthesis becomes less sensitive with age, older adults benefit from 30–40g per meal (vs 25g for younger adults) to trigger a meaningful MPS response.

One-Page Summary

• The RDA (0.8 g/kg) is a minimum, not a target.
• Lifters need 1.6–2.0 g/kg for muscle maintenance and gain (Morton 2018).
• Cutting calories? Bump to 2.0–2.4 g/kg (Longland 2016).
• ISSN's authoritative recommendation: 1.4–2.0 g/kg for anyone who trains (Jäger 2017).
• Distribute across 3–5 meals, 25–30g minimum per meal.
• High-protein diets are safe for healthy adults, even at 3+ g/kg long-term.
• Plant-based? Aim ~20% higher and combine sources for complete amino acid profiles.

Calculate Your Exact Target

Instead of estimating from a table, plug your weight, activity level, and goal into our free protein calculator. You'll get an exact daily protein target in grams within seconds.

Once you know the number, use our macro calculator to see how it fits into your total calorie budget and how much room you have left for carbs and fat. Or start with the TDEE / calorie calculator if you're not sure what your daily calorie target should be in the first place.

References

1. 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;52:376–384.

2. Longland TM, Oikawa SY, Mitchell CJ, Devries MC, Phillips SM. Higher compared with lower dietary protein during an energy deficit combined with intense exercise promotes greater lean mass gain and fat mass loss: a randomized trial. American Journal of Clinical Nutrition 2016;103(3):738–746.

3. Jäger R, Kerksick CM, Campbell BI, et al. International Society of Sports Nutrition Position Stand: Protein and Exercise. Journal of the International Society of Sports Nutrition 2017;14:20.

4. Antonio J, Ellerbroek A, Silver T, Vargas L, Peacock C. The effects of a high protein diet on indices of health and body composition: a crossover trial in resistance-trained men. Journal of the International Society of Sports Nutrition 2016;13:3.