How Much Protein Do You Need a Day?

Protein is having a moment. Yogurt, coffee, bread and even tortillas now come with "high protein" on the label, and searches for "how much protein do I need a day?" are rising in many countries. The honest answer: it depends on your body weight, your age and whether you train.

Here's what the research says, how to work out your own number, and how to reach it with ordinary food.

The baseline: 0.8 grams per kilogram

The usual starting point is the Recommended Dietary Allowance (RDA) set by the US National Academy of Medicine: at least 0.8 grams of protein per kilogram of body weight a day, or just over 7 grams for every 20 pounds.¹ For a 70 kg (154 lb) adult, that's about 56 grams a day.

That's a minimum to cover the needs of healthy adults, not a target for building muscle. And there's still relatively little solid information on the ideal amount for health.¹

How much protein to build muscle

If you strength-train, the evidence points higher. A 2018 meta-analysis pooled 49 randomised trials with 1,863 people who did resistance training for at least 6 weeks. Adding protein to their diets increased their gains in strength and muscle size, though modestly: on average about 0.3 kg more lean mass and 2.5 kg more on a one-rep max (the most you can lift once). The benefit levelled off at a total intake of about 1.6 g per kg of body weight a day. Above that, extra protein added no more lean mass.²

The International Society of Sports Nutrition (ISSN) lands in a similar place: 1.4–2.0 g per kg a day is enough for most people who exercise to build and maintain muscle.³

Notice what all of those trials had in common: people were training. Protein supports the work your muscles do. It doesn't replace it.

Older adults need a little more

As we age, muscle responds less to the protein we eat. An international expert group (PROT-AGE) recommends that people over 65 eat at least 1.0–1.2 g per kg a day, and 1.2 g or more if they exercise or are otherwise active. Most older adults with an acute or long-term illness need around 1.2–1.5 g per kg. The exception is people with severe kidney disease who aren't on dialysis, who may need to limit protein.⁴

Work out your own number

Multiply your body weight in kilograms (pounds ÷ 2.2) by the range that fits you:

• 0.8: the minimum for healthy adults
• 1.0–1.2: adults over 65
• 1.4–2.0: you strength-train regularly (about 1.6 is a sensible target)

For a 70 kg adult who lifts weights three times a week, 1.6 g per kg works out at about 110 grams a day. For a 60 kg adult, it's about 95 grams. Treat it as a daily average, not a number to hit exactly.

How much protein can your body absorb in one meal?

You've probably heard that your body can only "absorb" 20–25 grams of protein at a time and the rest is wasted. The real question is how much of a meal's protein can go to building muscle, and it's more than that.

The 20–25 gram figure came from studies of fast-digesting protein eaten on its own. A 2018 review found that larger doses mean more protein is burned for energy, but not all of the extra: some still goes to building tissue. For people who lift, the authors suggest about 0.4 g per kg per meal over at least four meals, and up to about 0.55 g per kg per meal at the top end.⁵

A 2023 study then tested a much bigger dose. In 36 healthy young men who had just done a whole-body resistance workout, 100 grams of milk protein produced a larger muscle-building response than 25 grams, and one that lasted more than 12 hours.⁶ It was one study, in young men, with a single protein drink, but it suggests there's no hard ceiling per meal.

So spreading protein over three or four meals is an easy way to reach your daily total. The ISSN suggests roughly 20–40 grams per serving, every 3–4 hours.³ But a big, protein-rich dinner isn't wasted.

Should you eat protein before or after a workout?

Either works. A meta-analysis of more than 20 randomised training studies found that once total protein intake was accounted for, eating protein right around the workout made no significant difference to strength or muscle growth. Total daily protein was the strongest predictor of muscle gain.⁷

The ISSN agrees that protein helps whether you have it before or after training, and notes that a workout's muscle-building effect lasts at least 24 hours, although it fades with time.³ So have a normal meal with some protein before or after training, whichever suits your day.

Protein from everyday food

You don't need special products to reach these numbers. As a rule of thumb from the US National Library of Medicine, each of these portions has about 7 grams of protein:⁸

• 30 g (1 oz) of meat, fish or poultry
• 1 large egg
• ¼ cup (60 ml) of tofu
• ½ cup of cooked beans or lentils

Low-fat dairy and whole grains add more, and you don't need animal products to get all the protein you need.⁸ A day might look like this:

• Breakfast: 2 eggs on wholegrain toast, about 14 g from the eggs alone.
• Lunch: lentil soup or salad. A cup of cooked lentils has about 18 g of protein, plus 15 g of fibre.¹
• Dinner: a 120 g (4 oz) portion of chicken, fish or lean meat, about 28 g.
• Snacks: milk, yogurt or cheese. The protein per serving is on the label.

That's about 60 g before counting the bread, dairy and snacks. To reach 110 g, you'd add a bigger dinner portion, an extra egg and a dairy snack or two.

For the healthiest mix, Harvard's nutrition experts suggest choosing fish, poultry, beans and nuts, limiting red meat and cheese, and avoiding processed meats such as bacon and cold cuts.¹

Are "high-protein" products worth it?

Protein yogurt, coffee, bread and bars all add protein, but it never comes alone. Every food is a "package" of protein plus fats, fibre, sodium and more, and that package is what's likely to make the difference for your health.¹ Before paying extra, compare the label with the regular version: how much more protein do you get, and how much more sugar, salt and cost?

Protein powder is just another convenient food. It can help if you struggle to reach your target with meals, but people who exercise can get enough protein from whole foods.³ In the US, protein powders, like other supplements, aren't regulated by the FDA for safety, and some contain added sugars, so read the label.¹

Is a high-protein diet safe?

For healthy adults, the evidence is reassuring. A 2018 meta-analysis of 28 trials with 1,358 people found that higher-protein diets (at least 1.5 g per kg, or 100 g or more a day) didn't harm kidney function in adults without kidney disease.⁹ Still, there's no need to go overboard,¹ and in the training trials, more than about 1.6 g per kg added no more muscle.²

It's different if you have a health condition. People with kidney or liver disease need to manage their protein intake following their doctor's guidance,¹ and older adults with severe kidney disease may need to limit it.⁴ If you have a long-term condition, or you're not sure, ask your doctor or a registered dietitian before raising your intake.

Put the protein to work

Protein builds muscle when your muscles have a reason to grow. If you're new to strength training, the 3-Day Full Body program works every major muscle group three times a week with compound-focused sessions. Once that feels routine, the 4-Day Upper / Lower split trains each half of the body twice a week with more volume. You can follow both in the TrainSmart app.

How to start this week

1. Work out your number using the ranges above.
2. Check one typical day with the 7-gram portions and food labels.
3. Fill the gaps. If you're short, add a protein food to the meal that has the least.
4. Train for it. Two or three strength sessions a week give that protein a job to do.

You don't need to count every gram forever: a few days of checking shows whether your usual meals cover your needs.