Most healthy adults need about 0.8 grams of protein per kilogram of body weight per day, which works out to roughly 0.36 grams per pound. For a 150-pound person, that’s around 54 grams daily. But that number is a minimum to prevent deficiency, not necessarily the amount that’s best for your health goals. Depending on your age, activity level, and whether you’re trying to lose weight or build muscle, the right target can be significantly higher.
The Baseline: What the RDA Actually Means
The Recommended Dietary Allowance of 0.8 g/kg/day supplies roughly 10% of total daily calories for a relatively active adult. This figure was set to meet the basic protein needs of 97.5% of the healthy population, but “meeting basic needs” and “optimizing health” are not the same thing. The RDA prevents protein deficiency. It doesn’t account for muscle maintenance as you age, recovery from exercise, or the metabolic advantages of eating more protein when you’re trying to lose fat.
Think of 0.8 g/kg as the floor, not the ceiling. Most nutrition researchers now consider it too conservative for many groups, which is why specific recommendations for older adults, athletes, and people managing their weight all land well above it.
Higher Needs for Adults Over 65
Muscle loss accelerates after age 65, and the body becomes less efficient at using dietary protein to rebuild tissue. Researchers now recommend that older adults consume 1.0 to 1.2 grams of protein per kilogram of body weight each day to help prevent sarcopenia, the gradual loss of muscle mass and strength that contributes to falls, fractures, and loss of independence. For a 160-pound older adult, that translates to roughly 73 to 87 grams per day, a meaningful jump from the standard RDA of about 58 grams.
Spreading protein across meals matters here too. Older adults appear to benefit from hitting at least 30 grams of protein in one or two meals per day, rather than concentrating it all at dinner or spreading it too thin across snacks.
Protein for Weight Loss Without Muscle Loss
When you eat fewer calories than you burn, your body doesn’t just tap into fat stores. It also breaks down muscle for energy, especially if protein intake is low. Eating more protein during a caloric deficit helps spare that muscle tissue while you lose fat, and it keeps you feeling fuller between meals.
A systematic review of adults with overweight or obesity found that protein intake above 1.3 g/kg/day was associated with actual increases in muscle mass, even during weight loss. Intake below 1.0 g/kg/day, on the other hand, raised the risk of losing muscle along with the fat. The range that consistently preserved lean mass and improved body composition across age groups was 1.2 to 1.6 g/kg/day. For a 180-pound person, that means roughly 98 to 131 grams of protein daily.
This higher range also helps with appetite. Protein is the most satiating macronutrient, meaning it suppresses hunger more effectively than the same number of calories from carbohydrates or fat. If you’ve ever noticed that a breakfast of eggs keeps you satisfied until lunch while toast and jam doesn’t, that’s the effect at work.
How Much Your Body Can Use in One Meal
Your muscles can only ramp up their repair and growth process so much from a single dose of protein. Research shows that about 30 grams of protein in a meal is enough to maximally stimulate muscle building. A study using beef found that a 30-gram serving triggered the full response, and larger portions didn’t push it any higher.
That said, the picture is slightly more nuanced. People who eat one or two meals per day with at least 30 to 45 grams of protein tend to have more leg lean mass and greater knee strength than those who never reach that threshold in any meal. The takeaway is practical: rather than eating 10 grams of protein at breakfast and 60 grams at dinner, aim for at least 25 to 30 grams at two or three meals throughout the day. A chicken breast, a cup of Greek yogurt with nuts, or a can of tuna each get you into that range.
Protein Quality: Plant vs. Animal Sources
Not all protein is absorbed equally. Animal sources like eggs, dairy, fish, poultry, and meat contain all the essential amino acids your body can’t make on its own, and they tend to be more digestible. When researchers compare digestion efficiency scores, animal-based proteins consistently outperform plant-based ones. One study measuring the amino acid absorption from animal-based burgers versus plant-based burgers in a pig model (pigs digest protein similarly to humans) found notably higher scores for the animal versions.
This doesn’t mean plant protein is inadequate. It means you may need to eat a bit more of it and vary your sources. Beans, lentils, tofu, tempeh, nuts, and whole grains each supply different amino acids. Combining them throughout the day, not necessarily at the same meal, gives your body the full set it needs. If you eat entirely plant-based, aiming toward the higher end of your protein target helps compensate for the lower digestibility.
Protein Needs During Pregnancy
Protein requirements rise during pregnancy to support the growth of the placenta, the baby, and expanded blood volume. The increase is modest in the first trimester, roughly 1 extra gram per day, but climbs substantially as the pregnancy progresses. By the third trimester, recommendations call for an additional 28 to 31 grams of protein daily on top of what a non-pregnant woman would need. For most women, that puts the daily target somewhere around 75 to 100 grams in late pregnancy.
The second trimester falls in between, with an estimated additional 9 grams per day. Since appetite and meal tolerance often shift during pregnancy, spreading protein across smaller, more frequent meals can make it easier to hit these numbers, especially when nausea or reflux makes large meals uncomfortable.
Is Too Much Protein Dangerous?
There is no formally established upper limit for protein intake in healthy adults. However, intake above 2 grams per kilogram of body weight per day is generally considered excessive, and there’s little evidence that going that high provides additional benefits for most people. For a 150-pound person, that threshold would be about 136 grams daily.
The primary concern with very high protein intake involves the kidneys. Filtering the byproducts of protein metabolism is part of normal kidney function, but consistently large amounts can strain kidneys that are already compromised. If you have existing kidney disease or are at higher risk for it (due to diabetes or high blood pressure, for example), high-protein diets deserve a closer conversation with your care team. For people with healthy kidneys, intakes in the 1.2 to 1.6 g/kg range have not shown evidence of harm.
Putting It Together
Here’s a quick reference based on body weight in kilograms (divide your weight in pounds by 2.2):
- Baseline for healthy adults: 0.8 g/kg/day
- Adults over 65: 1.0 to 1.2 g/kg/day
- Weight loss while preserving muscle: 1.2 to 1.6 g/kg/day
- Third trimester of pregnancy: baseline plus 28 to 31 g/day
- Excessive intake (little added benefit): above 2.0 g/kg/day
Regardless of where your target falls, distributing protein across meals in portions of at least 25 to 30 grams makes it more useful to your muscles than loading it all into one sitting. And if your protein comes mainly from plants, aim for the higher end of your range and mix your sources to cover all the essential amino acids.