Most healthy adults need at least 0.8 grams of protein per kilogram of body weight per day, which works out to about 0.36 grams per pound. For a sedentary 140-pound person, that’s roughly 53 grams daily. But that baseline number is a minimum to prevent deficiency, not necessarily an optimal target, and your actual needs shift depending on your age, activity level, and goals.
How to Calculate Your Baseline
The simplest method is to multiply your body weight in pounds by 0.36. A 180-pound person lands at about 65 grams per day; a 200-pound person, about 72 grams. If you prefer metric, multiply your weight in kilograms by 0.8. These numbers assume you’re a generally healthy adult who isn’t especially active and isn’t trying to build muscle or lose fat. For many people, this is enough to maintain normal body function, but it’s worth understanding that the RDA was designed to cover the minimum needs of 97.5% of the population. It’s a floor, not a ceiling.
Protein Needs for Active People
If you exercise regularly, your protein requirements increase meaningfully. People who do moderate exercise like jogging, swimming, or group fitness classes generally do well with 1.1 to 1.5 grams per kilogram of body weight. If you lift weights or train for endurance events like marathons or long cycling races, that range climbs to 1.2 to 1.7 grams per kilogram. For a 170-pound lifter, the upper end of that range is about 131 grams per day.
These higher intakes support muscle repair and growth. Your muscles break down slightly during intense exercise, and the amino acids from dietary protein are the raw materials your body uses to rebuild them stronger. Falling short doesn’t just slow muscle gains; it can leave you more sore and slower to recover between sessions.
Why Protein Timing Matters
Spreading your protein across meals matters more than most people realize. Your muscles can only use so much protein at once to trigger repair and growth. Research suggests that roughly 25 to 40 grams of high-quality protein per meal is the effective range for most adults. This is partly because your body needs a certain concentration of leucine, a key amino acid, to flip the switch on muscle rebuilding. A meal with around 2.5 to 3 grams of leucine appears to be the threshold, and you typically hit that with 25 to 30 grams of animal protein or a somewhat larger serving of plant protein.
The practical takeaway: eating 90 grams of protein in one sitting and almost none the rest of the day is less effective than splitting it into three meals of 30 grams each. If your daily target is higher, four meals work even better.
Protein Needs After 65
Older adults need more protein than younger ones, not less. After 65, your body becomes less efficient at using dietary protein to maintain muscle, a shift that contributes to the gradual loss of muscle mass and strength known as sarcopenia. The PROT-AGE study group, an international panel focused on nutrition in aging, recommends that adults over 65 aim for 1.0 to 1.2 grams per kilogram per day as a baseline. That’s 25 to 50% more than the standard RDA.
Older adults who are physically active should aim for the higher end, at or above 1.2 grams per kilogram. Those managing an acute illness or chronic disease often need 1.2 to 1.5 grams per kilogram to prevent further muscle loss. The one major exception is people with advanced kidney disease (specifically those whose kidneys are functioning below about 30% capacity and who are not on dialysis), who may need to limit protein to avoid overtaxing their kidneys.
Protein During Pregnancy and Breastfeeding
Protein needs rise progressively during pregnancy. In the first trimester, the increase is negligible, just a gram or two above your normal intake. By the second trimester, you need roughly 9 to 10 extra grams per day. In the third trimester, that jumps to about 28 to 31 additional grams daily, reflecting the rapid growth happening in the final months. For a woman who normally needs around 50 grams, third-trimester needs could reach 78 to 81 grams per day.
During breastfeeding, the additional requirement is about 19 grams per day in the first six months, dropping to around 13 grams per day once the baby starts eating solid foods and nursing less. Some guidelines express this as roughly 1.1 to 1.2 grams per kilogram of body weight per day.
Protein for Weight Loss
When you eat fewer calories than you burn, your body doesn’t just pull energy from fat. It also breaks down muscle, especially if your protein intake is low. Higher protein intakes help preserve lean mass during a caloric deficit, which matters because muscle is what keeps your metabolism running and your body functional as the scale drops. Adequate protein paired with resistance exercise is the most effective combination for holding onto muscle while losing fat.
There’s a nuance here, though. Research shows that while high protein preserves muscle mass, pushing protein excessively high doesn’t necessarily improve strength or metabolic outcomes compared to a moderate increase. Most people cutting calories do well targeting the 1.2 to 1.6 grams per kilogram range. Protein also has a strong effect on appetite. It’s the most satiating macronutrient, meaning it keeps you feeling full longer than the same number of calories from carbohydrates or fat, which makes sticking to a calorie deficit considerably easier.
Animal vs. Plant Protein Quality
Not all protein sources are created equal. The key differences come down to two things: whether a food contains all the essential amino acids your body can’t make on its own, and how well your gut actually absorbs them. Animal proteins like beef, pork, chicken, eggs, and dairy score consistently high on both counts. They contain all essential amino acids in proportions your body can readily use.
Plant proteins are more variable. Research from the University of Illinois comparing burgers found that beef and pork scored significantly higher on protein quality measures than plant-based alternatives. The pea-protein-based burger scored lowest, with sulfur-containing amino acids (methionine and cysteine) as its weak point. The soy-based burger performed better, scoring comparably to lean beef for adults and adolescents, though still falling short for young children.
This doesn’t mean plant protein is inadequate. It means that if you eat mostly or entirely plant-based, you benefit from eating a variety of protein sources throughout the day (legumes, grains, nuts, soy, seeds) so the amino acid gaps in one food get filled by another. You may also need to aim for the higher end of protein recommendations to compensate for slightly lower digestibility.
Is Too Much Protein Dangerous?
For healthy people, high-protein diets are not known to cause kidney damage or other medical problems. This is one of the more persistent nutrition myths. Your kidneys do work harder to process the byproducts of protein metabolism, but healthy kidneys handle this without issue.
The situation is different if you already have kidney disease. A high-protein diet can accelerate the decline in kidney function because damaged kidneys struggle to clear the waste products efficiently. The same caution applies to people with diabetes, which can affect kidney health over time. If you have either condition, your intake should be guided by your specific level of kidney function rather than general population guidelines.