Most adults need at least 0.8 grams of protein per kilogram of body weight per day. That’s the current Recommended Dietary Allowance (RDA), and for a 150-pound (68 kg) person, it works out to about 54 grams. But that number represents the minimum to avoid deficiency, not necessarily the amount that’s best for your health, body composition, or fitness goals. Depending on your age, activity level, and whether you’re trying to lose fat or build muscle, your ideal intake could be double that baseline or more.
The Baseline: 0.8 Grams Per Kilogram
The RDA of 0.8 g/kg per day applies to all adults regardless of age and is designed to meet the protein needs of 97 to 98 percent of the population. It’s calculated from the estimated average requirement of 0.6 g/kg, which is the bare minimum to maintain nitrogen balance, plus a safety margin. For most sedentary, healthy adults who aren’t trying to change their body composition, hitting this target is sufficient.
Here’s what that looks like in practice for a few body weights:
- 130 lbs (59 kg): ~47 g/day
- 150 lbs (68 kg): ~54 g/day
- 180 lbs (82 kg): ~66 g/day
- 200 lbs (91 kg): ~73 g/day
For context, a chicken breast has roughly 30 grams of protein, a cup of Greek yogurt about 15 to 20 grams, and two eggs around 12 grams. Many people hit the RDA without trying. The more interesting question is whether you’d benefit from going higher.
Building Muscle: 1.6 to 2.2 Grams Per Kilogram
If you’re doing resistance training and want to maximize muscle growth, the evidence points to a daily intake of about 1.6 g/kg as the threshold where the muscle-building benefits of additional protein start to plateau. A large meta-analysis found that protein supplementation beyond 1.6 g/kg per day failed to produce further gains in muscle size. The practical range is 1.6 to 2.2 g/kg per day, with the upper end offering a buffer for individual variation.
For a 150-pound person, that translates to roughly 109 to 150 grams of protein daily. For a 200-pound person, it’s about 146 to 200 grams. That’s a meaningful amount of food and typically requires deliberate planning: protein at every meal, possibly a shake or high-protein snack between meals.
Per-meal dosing matters too. Research shows that roughly 0.4 g/kg per meal, spread across at least four meals, is the most effective strategy for keeping muscle protein synthesis elevated throughout the day. For a 150-pound person, that’s about 27 grams per meal. Going significantly below that at any single meal means you’re leaving some muscle-building potential on the table, even if your daily total is adequate.
Losing Weight Without Losing Muscle
When you’re eating in a calorie deficit, your body doesn’t just burn fat. It also breaks down muscle for energy, especially if protein intake is low or you’re not exercising. Higher protein intake during weight loss helps preserve lean mass, and resistance training amplifies that protective effect.
For people with obesity undergoing weight loss, recommendations typically range from 1.0 to 1.2 g/kg for sedentary individuals and above 1.2 g/kg for those who exercise. Research shows that higher protein diets during calorie restriction preserve an additional 400 to 800 grams of lean mass compared to standard protein diets. That may sound modest, but over months of dieting, it adds up and makes a real difference in metabolic rate and how your body looks at a lower weight.
For leaner individuals cutting weight, such as athletes or bodybuilders, protein needs climb even higher. Intakes of 2.3 to 3.1 g/kg per day have been recommended to retain lean mass when body fat is already relatively low. The leaner you are, the more aggressively your body will target muscle during a deficit, and the more protein you need to counteract that.
Protein Needs After Age 65
Aging muscles become less responsive to protein. This phenomenon, called anabolic resistance, means that the same amount of protein that triggers robust muscle repair in a 25-year-old produces a weaker response in a 70-year-old. Older muscles need a greater dose of amino acids to reach the same level of stimulation.
This is why many researchers argue that the standard 0.8 g/kg recommendation is insufficient for older adults. Higher intakes, generally in the range of 1.0 to 1.2 g/kg per day or more, are proposed as a strategy to slow the gradual loss of muscle mass and strength that accelerates after 65. This age-related muscle loss primarily affects fast-twitch muscle fibers, which are critical for generating the kind of explosive strength you need to catch yourself during a stumble or rise from a chair.
Per-meal protein targets also shift upward with age. While younger adults maximize muscle protein synthesis with about 20 grams of high-quality protein per meal, some older adults may need closer to 40 grams per meal to achieve the same effect.
Plant Protein vs. Animal Protein
Not all protein is equally useful to your muscles. Plant-based proteins are generally less digestible than animal proteins because of their molecular structure: they contain more tightly folded configurations that resist breakdown in the gut. Fiber and compounds like phytic acid and tannins in plant foods can further reduce how much protein your body actually absorbs.
Plant proteins also tend to be lower in essential amino acids, particularly leucine, which is the primary trigger for muscle protein synthesis. Animal proteins average about 8.8% leucine content, while plant proteins average around 7.1%. Dairy proteins can exceed 10%. Beyond leucine, legumes like beans and lentils are low in sulfur-containing amino acids, while grains like wheat and rice are low in lysine. When any single essential amino acid is missing, the others can’t be fully used for building muscle and are instead broken down and discarded.
None of this means plant-based diets can’t meet your protein needs. It does mean that if you rely primarily on plant sources, you’ll benefit from eating a higher total amount of protein to compensate for lower digestibility, combining complementary sources (grains with legumes, for example) to cover amino acid gaps, and including soy, which is the plant protein closest to animal sources in overall quality.
How to Spread Protein Across the Day
Many people eat most of their protein at dinner, with relatively little at breakfast and lunch. Some research in younger adults shows that distributing protein evenly across meals produces higher overall muscle protein synthesis compared to this skewed pattern. The optimal approach, based on current evidence, is roughly 0.4 g/kg at each of four meals. For someone weighing 150 pounds, that’s four meals of about 27 grams of protein each.
That said, the evidence isn’t entirely consistent. Some trials in middle-aged and older adults found no clear advantage of even protein distribution over a skewed pattern for preserving lean mass during weight loss or maintaining protein balance. Total daily protein intake appears to matter more than how you divide it up. If hitting an even distribution feels impractical, prioritizing your daily total is the more important goal.
Is Too Much Protein Dangerous?
High-protein diets are commonly defined as anything above 1.2 to 2.0 g/kg per day, with intakes above 1.5 g/kg generally considered high. For healthy adults with normal kidney function, there’s no strong evidence that high protein intake causes kidney damage. The kidneys do work harder to process the byproducts of protein metabolism, but in healthy organs, this increased workload doesn’t appear to cause harm.
The picture changes for people with existing kidney disease or those with a single kidney. Individuals with one kidney are generally advised to stay below 1.2 g/kg per day and to keep sodium intake moderate to avoid placing unnecessary strain on their remaining kidney.
For most people, the practical ceiling isn’t kidney safety but diminishing returns. Beyond 2.2 g/kg per day, additional protein doesn’t contribute meaningfully to muscle growth. The extra calories still count, and protein-rich foods can be expensive. Unless you’re in a steep calorie deficit while already lean, there’s little reason to push intake above that upper range.