Most 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 150-pound person, that’s roughly 54 grams. For someone at 180 pounds, it’s about 65 grams. But that baseline number is a minimum to prevent deficiency, not necessarily the amount that’s optimal for your goals, age, or activity level.
The Baseline: What the RDA Actually Means
The Recommended Dietary Allowance of 0.8 grams per kilogram was set to cover the needs of 97.5% of healthy, sedentary adults. It’s the amount required to maintain basic nitrogen balance, meaning your body isn’t breaking down more protein than it’s building. For many people, especially those who are young, relatively inactive, and eating a varied diet, hitting this number is easy without much thought.
But the RDA wasn’t designed with muscle preservation, weight loss, athletic performance, or aging in mind. It’s a floor, not a ceiling. That distinction matters because a growing body of evidence suggests many people benefit from eating well above that minimum.
If You’re Building Muscle or Training Hard
For anyone doing regular strength training or trying to add muscle, the target jumps significantly. Sports nutrition experts largely agree on a range of 1.6 to 2.2 grams per kilogram per day to maximize the muscle-building response. For a 170-pound person, that translates to roughly 123 to 170 grams daily.
The lower end of that range (1.6 g/kg) captures most of the benefit. Going above 2.2 g/kg doesn’t appear to offer additional muscle growth for most people, though it’s unlikely to cause harm in otherwise healthy individuals. If you’re in a calorie deficit while training, aiming toward the higher end of the range helps preserve muscle while you lose fat.
How to Spread Protein Across Meals
Your body can only use so much protein for muscle repair in a single sitting. Research shows that muscle protein synthesis ramps up as you eat more protein in a meal, but the response plateaus at around 30 grams per serving. Eating 60 grams in one meal doesn’t double the muscle-building effect compared to 30 grams. In a study using beef as the protein source, 30 grams was enough to maximally stimulate protein synthesis, and larger portions didn’t improve the response.
This means distribution matters. If your daily target is 120 grams, you’ll get more benefit from four meals with 30 grams each than from one massive protein shake and two low-protein meals. People who consistently hit at least 30 grams per meal tend to have greater leg lean mass and stronger knee extensors than those who load protein unevenly throughout the day, even when total daily intake is similar.
Protein for Weight Loss
Protein is the most satiating macronutrient. Gram for gram, it keeps you fuller longer than carbohydrates or fat, which can naturally reduce how much you eat when you’re not strictly counting calories. Higher-protein diets also increase thermogenesis, the energy your body burns during digestion. Protein has a relatively low “energy efficiency,” meaning your body uses more calories to process it compared to other macronutrients. Over time, this adds up.
There isn’t one magic number for weight loss, but intakes in the range of 1.2 to 1.6 grams per kilogram are commonly used in research and tend to produce better satiety and body composition results than sticking to the RDA. For a 160-pound person, that’s about 87 to 116 grams per day.
Adults Over 65 Need More
Aging muscles become less responsive to protein. The same meal that triggers a strong muscle-building signal in a 30-year-old produces a blunted response in a 70-year-old, a phenomenon researchers call “anabolic resistance.” At the same time, older adults lose muscle mass at a rate of roughly 3 to 8 percent per decade after age 30, accelerating after 60. This progressive loss, called sarcopenia, increases the risk of falls, fractures, and loss of independence.
To counter this, researchers recommend that adults over 65 aim for 1.0 to 1.2 grams per kilogram per day. That’s 25 to 50 percent more than the standard RDA. For a 155-pound older adult, the target becomes about 70 to 85 grams daily. Despite this evidence, the official RDA for older adults remains 0.8 g/kg, the same as for younger adults. Many geriatric nutrition experts consider that insufficient.
Pregnancy and Breastfeeding
Protein needs rise during pregnancy, though the increase is modest in the first trimester (only about 1 extra gram per day) and climbs substantially by the third trimester. By late pregnancy, you need roughly 28 to 31 additional grams per day on top of your normal requirement, depending on which set of guidelines you follow. That means a pregnant woman in her third trimester may need around 75 to 80 grams daily, or approximately 1.0 gram per kilogram of body weight.
During breastfeeding, the additional need is about 19 to 23 grams per day in the first six months, dropping to around 13 grams after that as the baby starts eating solid foods. In practical terms, most women in countries with good food access can meet these needs through a regular diet without supplements, as long as they’re eating enough total calories.
Plant-Based Diets and Protein Quality
If you eat a varied diet that includes legumes, grains, nuts, and soy, getting enough total protein on a plant-based diet is straightforward. Healthy adults following entirely plant-based diets in Western countries are generally not at risk of protein or amino acid deficiency.
The nuance is in protein quality. Plant proteins contain all nine essential amino acids, but the proportions aren’t as well matched to human needs as animal proteins. Legumes tend to be low in certain amino acids that grains have in abundance, and vice versa. This is why combining sources (beans with rice, hummus with bread, tofu with quinoa) improves the overall amino acid profile of your diet. You don’t need to combine them in the same meal, just over the course of a day.
Where it gets trickier is with highly processed plant-based meat alternatives. If you’re using these as direct one-to-one replacements for animal products long-term, the protein quality may not be equivalent. Paying attention to variety becomes more important. Some people on plant-based diets aim for the higher end of their protein range (closer to 1.0 to 1.2 g/kg rather than 0.8) to compensate for slightly lower digestibility, though this isn’t universally necessary.
Quick Reference by Goal
- General health (sedentary adult): 0.8 g/kg (about 0.36 g per pound)
- Weight loss or moderate activity: 1.2 to 1.6 g/kg
- Muscle building or intense training: 1.6 to 2.2 g/kg
- Adults over 65: 1.0 to 1.2 g/kg
- Late pregnancy: roughly 1.0 g/kg
- Breastfeeding: roughly 1.1 to 1.2 g/kg
To find your number, divide your weight in pounds by 2.2 to get kilograms, then multiply by the appropriate range. A 180-pound person focused on muscle gain, for example, would calculate: 180 ÷ 2.2 = 82 kg × 1.6 to 2.2 = 131 to 180 grams per day.