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. But that number is a baseline minimum for sedentary adults, and your actual needs could be significantly higher depending on your age, activity level, and goals.
The Baseline for Sedentary Adults
The Recommended Dietary Allowance (RDA) of 0.8 grams per kilogram has been the standard reference point for decades. It represents the minimum amount needed to meet basic nutritional requirements and prevent deficiency in a healthy adult who isn’t particularly active. For a 180-pound man, that comes to about 65 grams per day. For a 140-pound woman, about 51 grams.
The 2025-2030 Dietary Guidelines for Americans actually suggest a higher range: 1.2 to 1.6 grams per kilogram per day. That shift reflects growing evidence that the old RDA, while enough to prevent deficiency, isn’t necessarily enough for optimal health, especially as you age or increase your activity level.
How Exercise Changes the Number
If you regularly lift weights or train for endurance events like running or cycling, your protein needs jump to 1.2 to 1.7 grams per kilogram per day. For a 170-pound person, that’s 93 to 131 grams daily. The higher end of that range applies to people doing intense strength training or preparing for competition, while the lower end covers moderate, consistent exercise.
One common misconception is that building muscle requires dramatically more protein than a normal diet provides. In reality, the increase is meaningful but not extreme. A reasonable estimate: take your body weight in pounds, multiply by 0.36 for a lower target and 0.45 for an upper target, then add roughly 50 percent if you’re training hard. That extra bump is enough to support muscle repair and growth without the massive protein loads many fitness influencers promote.
Protein Needs After 65
Nearly half of all protein in the body is stored in muscle, and muscle mass naturally declines with age. This gradual loss, called sarcopenia, accelerates after 65 and increases the risk of falls, fractures, and loss of independence. To counteract it, researchers recommend older adults consume 1.0 to 1.2 grams of protein per kilogram of body weight per day, noticeably more than the standard 0.8-gram RDA.
Combining higher protein intake with regular resistance and endurance exercise makes a significant difference in preserving muscle. One important exception: people with kidney disease should not increase protein intake without medical guidance, since extra protein creates more filtering work for the kidneys.
During Pregnancy and Breastfeeding
Protein needs increase gradually during pregnancy. In the first trimester, the additional requirement is negligible, less than a gram per day above normal. By the second trimester, you need roughly 9 to 10 extra grams daily, and by the third trimester, that jumps to about 28 to 31 extra grams per day. For a woman who normally needs around 48 grams, that means roughly 76 to 79 grams daily in late pregnancy.
During breastfeeding, the extra demand stays elevated. Exclusive breastfeeding in the first six months calls for about 19 additional grams of protein per day. After six months, when breastfeeding is typically supplemented with solid foods, the extra need drops to around 13 grams.
What Kids and Teens Need
Children’s protein requirements are lower in absolute terms but still important for growth. The RDA by age:
- Ages 1 to 3: 13 grams per day
- Ages 4 to 8: 19 grams per day
- Ages 9 to 13: 34 grams per day
- Ages 14 to 18: 46 grams for girls, 52 grams for boys
Most children in developed countries meet or exceed these numbers through a normal diet without any special effort. The protein share of total calories should fall between 10 and 30 percent for kids over age 4.
Spreading Protein Across the Day
Your body can only use so much protein at once for muscle repair and maintenance. To get the most benefit, aim to spread your intake across three or four meals rather than loading it all into dinner. Each meal should contain enough protein to deliver 700 to 3,000 milligrams of leucine, the amino acid that triggers muscle rebuilding. In practical terms, that translates to about 20 to 40 grams of protein per meal, depending on the source.
Spacing meals about three to four hours apart gives your body time to fully process each dose before the next one. This matters most for older adults and people trying to build or maintain muscle, since their bodies are less efficient at using protein in large single doses.
Animal vs. Plant Protein Sources
Animal proteins from meat, fish, eggs, and dairy contain all essential amino acids in the right proportions and are more easily digested. When researchers compare digestibility scores, animal-based proteins consistently outperform plant-based ones. That doesn’t mean plant protein is inadequate, but it does mean you need to be more intentional about variety.
Plant sources like beans, lentils, tofu, nuts, and whole grains each tend to be low in at least one essential amino acid. Eating a range of plant proteins throughout the day covers those gaps without requiring careful combining at every meal. If you eat a fully plant-based diet, aiming for the higher end of your protein range is a practical way to compensate for the lower digestibility of individual sources.
Can You Eat Too Much Protein?
For people with healthy kidneys, moderately high protein intake is generally safe. But consistently eating well above your needs does create extra work for your kidneys, which have to filter out the additional acids and waste products. Over time, very high protein diets can increase inflammation and oxidative stress throughout the body, making it harder for your kidneys and other organs to function at their best.
There’s no established hard ceiling for protein, but the practical takeaway is straightforward: more isn’t always better. Going from 0.8 to 1.2 or 1.6 grams per kilogram offers real benefits for most people. Doubling or tripling the RDA on a sustained basis, as some extreme diet plans suggest, carries risk without proportional reward. If you have any degree of kidney disease, even a modest increase in protein deserves a conversation with your doctor first.