Most women need between 1.4 and 2.0 grams of protein per kilogram of body weight per day to build muscle effectively. For a 140-pound (64 kg) woman, that works out to roughly 90 to 128 grams of protein daily. The exact amount depends on your training intensity, whether you’re eating in a caloric deficit, and your age.
The Daily Target in Grams
The International Society of Sports Nutrition recommends 1.4 to 2.0 g/kg/day for physically active individuals looking to build and maintain muscle. That range is broad because it covers everything from moderate exercise to serious strength training. If you’re consistently lifting heavy, aiming for the higher end of that range (closer to 2.0 g/kg) is a reasonable target.
Here’s what that looks like at different body weights:
- 120 lbs (54 kg): 76 to 108 g protein per day
- 140 lbs (64 kg): 90 to 128 g protein per day
- 160 lbs (73 kg): 102 to 146 g protein per day
- 180 lbs (82 kg): 115 to 164 g protein per day
If you’re eating in a caloric deficit while trying to hold onto muscle, the number goes up. Research suggests that resistance-trained individuals cutting calories may need 2.3 to 3.1 g/kg/day to preserve lean mass. That’s a significant jump, and it reflects the reality that your body is more likely to break down muscle for energy when calories are low. Higher protein intake protects against that.
How Much Protein Per Meal
Your body can only use so much protein at once to stimulate muscle growth. Research on female athletes points to roughly 0.31 grams per kilogram of body weight per meal as the dose that maximizes muscle protein synthesis. For a 140-pound woman, that’s about 20 grams of protein per meal.
The key amino acid driving this process is leucine, which directly triggers the signaling pathway in your muscles that starts building new tissue. You need about 3 to 4 grams of leucine per meal to fully activate that process, which corresponds to roughly 25 to 30 grams of protein from a high-quality source. A chicken breast, a cup of Greek yogurt with some nuts, or a scoop and a half of whey protein all get you there.
Spacing your protein across four or five meals every three to four hours gives your muscles repeated signals to grow throughout the day. Eating 120 grams of protein is less effective if 80 of those grams come at dinner. Spreading it evenly matters more than most people realize.
Timing Around Workouts Matters Less Than You Think
The idea that you need to chug a protein shake within 30 minutes of your last set is one of the most persistent myths in fitness. A large meta-analysis found that immediate protein consumption before or after a workout does not significantly enhance muscle growth or strength compared to eating it at other times. When researchers looked more closely, any benefits that appeared in timing studies were actually explained by the fact that those people were simply eating more total protein.
Total daily protein intake is the strongest predictor of muscle growth. If you’re hitting your daily target and distributing it reasonably across meals, the exact minute you eat relative to your workout is not a major factor. That said, having a protein-rich meal within a few hours on either side of training is still a sensible habit.
Protein Needs After Menopause
Women over 65 face a challenge called anabolic resistance, where muscles become less responsive to the protein you eat. The current general recommendation for adults (0.8 g/kg/day) was designed around basic nitrogen balance, not muscle function or physical performance. Researchers have criticized this standard because it has little relationship to actual muscular health.
Studies on postmenopausal women show that higher protein intakes are associated with better lean mass, strength, and physical performance. One study found that a diet providing about 1.3 g/kg/day effectively enhanced the effects of resistance training on lean body mass and muscle strength in elderly women. If you’re past menopause and lifting weights, treating 1.3 g/kg/day as a minimum rather than a target is a practical approach.
Plant Protein vs. Animal Protein
Animal proteins like meat, eggs, dairy, and fish contain all the essential amino acids in the proportions your muscles need, and they’re highly digestible. Plant proteins tend to be lower in one or more essential amino acids and are generally less digestible, meaning some of what you eat gets broken down for energy rather than directed toward muscle building.
That said, a systematic review of randomized controlled trials found that protein source did not significantly affect total lean mass gains or muscle strength when total protein intake was matched. Animal protein did produce a small but statistically significant advantage in percent lean mass (about 0.5% greater). The practical takeaway: if you eat a fully plant-based diet, you can still build muscle effectively, but you may need to eat a higher total amount of protein to compensate for lower digestibility and amino acid profiles. Combining different plant sources (legumes with grains, for instance) helps cover amino acid gaps.
Putting It All Together
For most women strength training to build muscle, the practical daily target falls between 1.6 and 2.0 g/kg of body weight. Distribute that across four or five meals of 25 to 40 grams each, spaced three to four hours apart. Prioritize protein sources that are rich in essential amino acids, whether that’s chicken, fish, eggs, dairy, tofu, or a mix of legumes and grains. If you’re in a caloric deficit, push toward the higher end of the range or beyond to protect the muscle you’re working to build. And if you’re over 60, the standard dietary recommendation of 0.8 g/kg is almost certainly not enough to support your training goals.