As a physician, I watch elderly patients slowly lose muscle and strength. After researching the data on protein, I could see the loss of muscle mass in my own parents. Most people do not notice until something goes wrong, like a fall or trouble getting out of a chair.

The good news is that this loss is not inevitable and can be reversed. Protein and strength training can slow it down and even reverse part of it. But there is a lot of confusing advice about how much protein you really need. In my own social circle, I have heard a few claim 1 gram per pound of protein. Let me clear it up with the numbers.

Watch the 14-minute whiteboard explainer:

For years the official amount was 0.8 grams of protein per kilogram of body weight each day. In 2026, a review of the new US Dietary Guidelines raised that to 1.2 to 1.6 grams per kilogram (Mozaffarian, JAMA 2026).

For an 80 kilogram (~175 lbs) adult, that is about 96 to 128 grams of protein a day, up from about 64 grams. That one change is what the rest of this issue explains.

To see why the number went up, it helps to know what the old 0.8 was really measuring. Protein is the body's main source of nitrogen, so researchers tracked how much nitrogen people ate against how much they lost. The point where the two match, called nitrogen balance, is simply where you stop losing body protein. Healthy young adults reach that point at only about 0.55 to 0.6 grams per kilogram, and 0.8 was set above it to add a safety margin. So 0.8 is already a cushion above the bare minimum.

The catch is that nitrogen balance only tells you that you are not running a deficit. It says nothing about building or keeping muscle, strength, and physical function. That is the whole problem after 40. The new 1.2 to 1.6 grams per kilogram target aims at those outcomes instead of just avoiding deficiency, which is why it is higher, and why the right number depends on your age and whether you train.

Starting around age 40, you slowly lose muscle. Muscle mass drops about 8 percent per decade until age 70, then about 15 percent per decade after that. Strength falls even faster, about 10 to 15 percent per decade, then 25 to 40 percent per decade after 70 (J Cachexia Sarcopenia Muscle 2025).

Older muscle also responds less to protein. After a meal, it builds muscle about 16 percent slower than young muscle does. Doctors call this anabolic resistance (Campbell et al., J Gerontol A 2023).

Here is the part most people get wrong. Extra protein builds muscle mostly when you also do resistance training, like lifting weights or using resistance bands. On its own, it does very little.

In one trial, healthy older adults drank 40 grams of whey protein every day for a full year. Without training, they gained zero extra muscle. The group that added heavy strength training gained real muscle and strength (Mertz et al., Am J Clin Nutr 2021).

Across many trials, extra protein plus training added about 0.77 kilograms of muscle. Extra protein with no training added about 0.08 kilograms, which was too small to count (Hudson et al., Adv Nutr 2020).

Yes. The benefit climbs as you go from 0.8 up toward 1.6 grams per kilogram, then it flattens out. A large review of 49 trials found that muscle gains stop improving at about 1.6 grams per kilogram a day (Morton et al., Br J Sports Med 2018). Another review of 105 trials put the main slowdown even earlier, around 1.3 grams per kilogram (Tagawa et al., Nutrition Reviews 2020).

Going above 1.6 is not harmful for healthy people, but it rarely builds more muscle. The tolerable upper limit is about 3.5 grams per kilogram, and staying above 2.0 for a long time deserves caution (Heymsfield and Shapses, N Engl J Med 2024).

The target range is the same for everyone over 40: 1.2 to 1.6 grams per kilogram to build muscle. What changes is the floor, which is the least you can get away with.

From 40 to 60, about 0.8 grams per kilogram may be enough to hold onto muscle if you are not very active. If you are between 40 and 60, not doing any resistance training, and not trying to lose weight, eating more than about 1.3 grams per kilogram does not clearly add muscle. Remember, it is the training combined with protein that results in increased strength and muscle.

After 60, 0.8 grams per kilogram is too low. In a small controlled trial, 29 men over 70 ate either 0.8 or 1.6 grams per kilogram for 10 weeks. The higher group gained about 1.5 kilograms of lean mass while the 0.8 group lost a little muscle (Mitchell et al., Am J Clin Nutr 2017). The direction is clear enough that after 60 it is safest to treat 1.2 as the minimum (Nunes et al., J Cachexia Sarcopenia Muscle 2022).

Spread your protein across the day instead of saving it for one big dinner. Each meal needs about 25 to 30 grams of protein, or at least 0.4 grams per kilogram, to fully switch on muscle building (Ely et al., Clin Nutr 2023). Older adults need the higher end because of anabolic resistance.

Here is a simple example. An 80 kilogram adult aiming for 1.2 grams per kilogram needs about 96 grams a day. That is about 32 grams at each of three meals. The exact timing around workouts matters much less than hitting that per meal amount (Jäger et al., J Int Soc Sports Nutr 2017).

So far the targets are grams per kilogram of your total body weight. For most people at a normal weight this works fine, because fat is only a small part of what they weigh (Nunes et al., J Cachexia Sarcopenia Muscle 2022).

It gets tricky if you carry a lot of extra fat. Fat tissue needs very little protein, so using your full body weight can tell you to eat far more than you actually need. One analysis found that total weight overestimated the real requirement in most people with extra weight. In that case, base the target on your fat free mass instead, at about 1.5 grams per kilogram of fat free mass a day (2025 obesity nutrition advisory).

Fat free mass is everything in your body that is not fat. It is simply your total weight minus the weight of your body fat. To find it, you need your body fat percentage, then:

Fat free mass = total weight × (100 minus your body fat percent) ÷ 100

For example, a person who weighs 100 kilograms at 30 percent body fat carries 30 kilograms of fat, so their fat free mass is 70 kilograms. At 1.5 grams per kilogram that is about 105 grams of protein a day. Using their full 100 kilograms at 1.6 would have said 160 grams, which is far too much.

You can get your body fat percentage from a body composition scale, a DEXA scan, which is the most accurate, or skinfold calipers. If you cannot measure it, use your ideal or adjusted body weight in place of your actual weight (2025 obesity nutrition advisory).

This is not just about looking strong. Losing muscle is one of the biggest reasons older adults fall, break bones, and lose their independence. Sarcopenia is one of the most under appreciated threats to healthy aging, yet protein combined with strength training is one of the few things proven to slow it down.

Getting these numbers right in your 40s, 50s, and 60s is really about staying steady on your feet for decades to come.

Here are the targets by age and goal in one place.

Remember:

It is never too late. Adults in their 70s and 80s build real muscle and strength when they combine enough protein with training (Nunes et al., J Cachexia Sarcopenia Muscle 2022; Morton et al., Br J Sports Med 2018).

You probably know a parent, a spouse, or a friend over 40 who wants to stay strong and independent. Share this, knowing a few simple numbers and a little strength training could help them hold onto their muscle for years, and it is worth a real conversation with their doctor. That is how Pareto Life grows.

References

Mozaffarian, JAMA 2026 · Mertz et al., Am J Clin Nutr 2021 · Morton et al., Br J Sports Med 2018 · Hudson et al., Adv Nutr 2020 · Tagawa et al., Nutrition Reviews 2020 · Heymsfield & Shapses, N Engl J Med 2024 · Mitchell et al., Am J Clin Nutr 2017 · Nunes et al., J Cachexia Sarcopenia Muscle 2022 · Campbell et al., J Gerontol A 2023 · Mapping Normative Muscle Health Metrics, J Cachexia Sarcopenia Muscle 2025 · Ely et al., Clin Nutr 2023 · Jäger et al., J Int Soc Sports Nutr 2017 · 2025 joint advisory on nutrition for obesity management