Protein Intake Per kg: The Complete Guide

If you've ever searched "how much protein do I need," you've probably landed on a dozen different numbers. Some say 1 gram per pound. Others say 0.8 grams per kilogram. Bodybuilding forums suggest 2 grams per pound. It's confusing — and most of the advice is either outdated, oversimplified, or written to sell you something.

The reality is that your protein intake per kg of body weight depends on your goal, your activity level, your age, and a few other factors. There's no single magic number that works for every person. This guide gives you the actual science — what leading research organizations recommend, how to calculate your personal target, and what it looks like in day-to-day eating.

What "Protein Per kg" Actually Means

Expressing protein needs per kilogram of body weight is how nutrition scientists and dietitians make recommendations that scale across different body sizes. Instead of giving everyone the same flat number — say, "eat 150 grams of protein" — the per-kg format adjusts automatically for your size.

A 60 kg woman and a 100 kg man have very different protein requirements even if they have the same fitness goal. Per-kg recommendations make the advice relevant regardless of where you start.

The math is simple:

Daily protein target (g) = your body weight (kg) × recommended g/kg

So if you weigh 75 kg and your goal calls for 1.8 g/kg:
75 × 1.8 = 135 grams of protein per day.

Not sure what your weight is in kilograms? Divide your weight in pounds by 2.2. So 165 lbs ÷ 2.2 = 75 kg.

How Much Protein Per kg Do You Need?

Here's what the research actually says, organized by goal and population. These ranges come from position statements by the International Society of Sports Nutrition (ISSN), the American College of Sports Medicine (ACSM), and the Academy of Nutrition and Dietetics (AND).

The 0.8 g/kg figure you often see is the Recommended Dietary Allowance (RDA) set by the Institute of Medicine. Here's the thing — the RDA is a minimum threshold to prevent deficiency in the average sedentary person, not an optimal target for anyone exercising or trying to change their body composition. For most active adults, it's too low.

Protein Targets by Goal: A Closer Look

Building Muscle

Gaining muscle requires a state called positive protein balance — you're building more muscle tissue than you're breaking down. Resistance training triggers the process, and dietary protein provides the amino acids that fuel it.

A 2018 meta-analysis by Morton and colleagues, published in the British Journal of Sports Medicine, analyzed 49 studies and found that protein supplementation significantly increased lean mass gains — with benefits leveling off around 1.62 g/kg per dayfor most people. That doesn't mean going higher hurts; it just means you'll see diminishing returns above roughly 2.2 g/kg for most natural lifters.

For advanced athletes who are already lean and training hard, pushing toward 2.2–2.5 g/kg makes sense. There's enough research to justify it, even if the extra muscle gained is marginal.

Example: Ethan weighs 80 kg and lifts weights four times a week. His target: 80 × 1.8 = 144 g protein per day.

Losing Weight While Keeping Muscle

When you cut calories, your body is at risk of burning muscle along with fat — especially if protein intake drops too low. Higher protein intake during a deficit helps you preserve lean body mass, stay fuller longer, and benefit from the thermic effect of food (protein burns more calories during digestion than carbs or fat do).

The ISSN recommends 1.6–2.4 g/kg during a caloric deficit. For very lean athletes doing an aggressive cut, research supports going even higher — up to 3.1 g/kg — though this is an edge case relevant mainly to bodybuilders near competition weight.

Read more in our guide on protein intake for weight loss.

Example: Sarah weighs 70 kg and is eating in a moderate calorie deficit. Her target: 70 × 2.0 = 140 g protein per day.

Maintenance and General Health

If you're not specifically focused on losing fat or building significant muscle — maybe you just exercise regularly and want to feel good — sitting somewhere in the 1.0–1.4 g/kgrange is a smart, sustainable target. It's enough to support muscle maintenance, immune function, and tissue repair without being difficult to hit from food alone.

If you're mostly sedentary (desk job, minimal exercise), 0.8–1.0 g/kg meets your basic physiological needs.

Protein Per kg for Special Groups

Older Adults (65 and Over)

Ageing reduces the body's efficiency at using dietary protein to build and repair muscle — a phenomenon researchers call anabolic resistance. To get the same muscle protein synthesis response as a younger person, older adults need more protein per kilogram.

The PROT-AGE Study Group recommends 1.0–1.2 g/kg per day as a baseline for healthy older adults, rising to 1.2–1.5 g/kg for those dealing with illness, injury, or significant muscle loss. Regular strength training alongside adequate protein is the most effective combination.

More on this in our article on protein intake for men over 40.

Pregnant Women

Protein needs climb considerably during pregnancy to support fetal growth, placental development, and expanded maternal tissue. The Dietary Reference Intakes recommend an additional 25 g of protein per day during pregnancy, bringing typical needs to around1.1–1.2 g/kg — though some research suggests higher needs in the second and third trimesters.

For a detailed breakdown, see our guide on protein intake during pregnancy.

Endurance Athletes

Marathon runners, cyclists, and triathletes often underestimate their protein needs because their training is built around carbohydrate fueling. But endurance exercise does break down muscle protein, and adequate intake supports recovery and adaptation. The ACSM and AND recommend1.2–1.6 g/kg for endurance athletes.

How to Calculate Your Daily Protein Target

Follow these steps:

1. Get your body weight in kilograms. If you know your weight in pounds, divide by 2.2. Example: 180 lbs ÷ 2.2 = 81.8 kg.
2. Choose your target g/kg range based on your goal, using the table above.
3. Multiply. 81.8 kg × 1.8 g/kg = approximately 147 g of protein per day.
4. Distribute across meals. Aim for 3–5 meals, each containing 25–45 g of protein. This is more effective for muscle protein synthesis than loading most of your protein into one meal.

You can also use our free Protein Intake Calculator to get a personalized target instantly — it accounts for your age, activity level, body composition, and goal, and gives you a range rather than just a single number.

If you want a more precise number based on your lean body mass rather than total weight, you can use the Body Fat Calculator first to estimate your body fat percentage, then base your protein target on your lean mass. This is especially useful for people who are carrying extra body fat.

Current or Goal Body Weight — Which Should You Use?

This is a common question. If you're significantly overweight, using your current body weight to calculate protein can push your target unrealistically high. A person who is 120 kg but whose goal weight is 85 kg doesn't need the protein intake of a 120 kg athlete.

The practical guideline: if you're more than 15–20% above your goal weight, use your goal body weight or your estimated lean body mass as the basis for calculation. For people who are already near their healthy weight, current body weight is fine.

How to Distribute Protein Through the Day

Total daily protein intake matters more than when exactly you eat it. But the distribution does have a meaningful effect on muscle protein synthesis, especially if you're training for hypertrophy.

Research supports eating approximately 0.4 g/kg per meal, spread across 3–5 meals. For a 75 kg person, that's about 30 g per meal across four meals — a very achievable target with normal food.

The old idea that your body can only absorb 20–30 g of protein per meal has been largely debunked. What research shows is that muscle protein synthesis response is stimulated most efficiently at around 20–40 g per meal for most people — but you can certainly eat more and still use the protein. It just won't all be used for muscle building.

Curious about the timing question specifically? Read our article on protein before or after workout for the research on the post-exercise window.

Common Mistakes People Make

Using Pounds Instead of Kilograms

The popular "1 gram per pound of body weight" rule is roughly equivalent to 2.2 g/kg — which sits at the high end of evidence-based ranges. It's not dangerous for healthy adults, but for most people doing moderate exercise, it's more than necessary. It tends to get popularized in bodybuilding circles where it originated as a simple, memorable guideline rather than a research-derived number.

Front-Loading Protein at Dinner

Eating 10 g at breakfast, 15 g at lunch, and 100 g at dinner is a common pattern — and it's suboptimal for muscle protein synthesis. Spreading protein more evenly throughout the day (while hitting your total) produces better results, particularly if muscle building is your goal.

Ignoring Protein Quality

Not all protein sources trigger the same muscle protein synthesis response. Complete proteins — those containing all nine essential amino acids, found in animal products, soy, and some other plant sources — are generally more effective for muscle building. Plant proteins often have lower leucine content, which is the amino acid most responsible for initiating protein synthesis.

If you're plant-based, you can still hit your targets — you just need to be thoughtful about combining sources. Our article on vegetarian protein sources for muscle gain breaks this down in detail.

Using the RDA as Your Optimization Target

The 0.8 g/kg RDA is designed to prevent deficiency in sedentary people, not to optimize body composition or performance. If you're active and treating 0.8 g/kg as your target, you're almost certainly under-eating protein.

Counting Supplements But Not Food

Protein powder counts toward your daily total — but so does the protein in every meal. Many people track their shake carefully while ignoring the protein in their actual food, creating a false picture of their intake. Log everything if accuracy matters to you.

What Happens When You Don't Get Enough Protein

Chronically low protein intake doesn't usually cause dramatic symptoms right away. The effects accumulate gradually, which is why many people don't notice until significant muscle has already been lost — particularly during weight loss phases or periods of illness.

Signs of consistently low protein intake include:

• Slow recovery after training
• Difficulty building or maintaining muscle despite consistent exercise
• Persistent hunger (protein is the most satiating macronutrient)
• Hair thinning or brittle nails
• Frequent illness (immune proteins depend on dietary amino acids)
• Fatigue and poor concentration

If you've been losing weight and noticing these signs, it's worth auditing your protein intake carefully. A common pattern: someone cuts calories aggressively, eats mostly carbs and vegetables, and wonders why they look "skinny fat" despite the scale moving. Inadequate protein during the deficit is usually the culprit.

Frequently Asked Questions