Short answer: most women over 40 who lift and want to keep their muscle do best at roughly 1.2 to 1.6 grams of protein per kilogram of body weight per day (about 0.55 to 0.73 grams per pound), spread over three or four meals with 25 to 40 grams at each. The official minimum of 0.8 g/kg is a floor that prevents deficiency. It is not a target for strength, bone and energy.
What is the RDA for protein, and why is it not enough after 40?
The US Recommended Dietary Allowance is 0.8 grams per kilogram of body weight (0.36 g per pound). It was set using nitrogen-balance studies, which measure what you need to avoid deficiency, not what you need to build or protect muscle, as Dr. Stacy Sims explains. Dr. Peter Attia makes the same point: the RDA is the minimum to maintain nitrogen balance and is far too low if your goal is to protect lean mass.
For a 150-pound woman (68 kg), the RDA works out to about 54 grams a day. That is roughly what two eggs, a cup of yogurt, one chicken breast and a handful of nuts add up to, with very little left for the training that midlife muscle actually responds to.
Why do protein needs go up in midlife?
Aging muscle becomes less responsive to protein, a pattern researchers call anabolic resistance. The PROT-AGE Study Group, an international expert panel, recommends at least 1.0 to 1.2 g/kg for older adults, 1.2 g/kg or more for those who exercise, and about 25 to 30 grams per meal to trigger muscle repair (Bauer et al., JAMDA, 2013). That paper covers people over 65, so read it as evidence for the floor, not a ceiling for your 40s and 50s.
What do Dr. Stacy Sims, Dr. Mary Claire Haver and Dr. Peter Attia recommend?
- Dr. Stacy Sims (exercise physiologist): 1.7 to 2.4 g/kg for active women. She also notes that research on women is still limited.
- Dr. Mary Claire Haver (OB-GYN): 1.3 to 1.6 g per kg of lean body weight, and 1.8 to 2.0 with regular strenuous exercise, according to her Pause Life guidance.
- Dr. Peter Attia (longevity physician): about 1 gram per pound, or 2.2 g/kg, in his practice.
They do not agree on one number, and that is the honest answer. Here is what the ranges look like for a 150-pound woman:
| Target | Per kg | Grams per day (68 kg) |
|---|---|---|
| RDA (minimum) | 0.8 | 54 |
| PROT-AGE floor for exercisers | 1.2 | 82 |
| Practical midlife target | 1.2 to 1.6 | 82 to 109 |
| Sims (active women) | 1.7 to 2.4 | 116 to 163 |
| Attia (1 g per lb) | 2.2 | 150 |
Math: 68 kg x 0.8 = 54; x 1.2 = 82; x 1.6 = 109; x 1.7 = 116; x 2.4 = 163. If you carry a lot of extra weight, calculate from your goal weight or lean mass instead, or the numbers get unrealistic fast.
So what should I actually aim for?
Start at 1.2 to 1.6 g/kg. That is 82 to 109 grams for a 150-pound woman. It sits above the floor the research supports, it is achievable with regular food, and it does not require a spreadsheet. Move toward 1.6 to 2.0 if you lift three or more days a week, are eating in a calorie deficit, or are on a weight-loss medication, where holding on to muscle matters even more (see GLP-1 and muscle loss and how to keep weight off afterward). The cost: more food volume, more grocery planning, and a bit more chewing. Many women find that trade easy once afternoon cravings drop.
How much protein should I eat per meal?
Aim for 25 to 40 grams at each of three or four meals, with 10 to 20 grams for a snack if you need one. Front-load it: most women eat the bulk at dinner and almost none at breakfast, and breakfast is where a protein anchor helps most (more in why you are tired by 2pm after 40). Per Dr. Sims, rough numbers are:
- 4 oz chicken, beef or pork: about 30 g
- 1 cup 2% cottage cheese: about 30 g
- One 3.5 oz can of tuna: about 30 g
- 1 cup low-fat Greek yogurt: about 20 g
A sample day near 105 grams: Greek yogurt and two eggs at breakfast (about 32 g), a can of tuna over greens at lunch (30 g), half a cup of cottage cheese as a snack (15 g), and 4 oz of chicken with vegetables at dinner (30 g).
Is protein enough on its own?
No. Protein gives your muscle the raw material, and lifting gives it the reason to use it. Without resistance training, extra protein is mostly just calories. Pair it with progressive strength work (strength training after 40), which also supports bone density. For the full food framework, see hormone-aware nutrition for women over 40, and if the scale is the frustration, start with why weight loss after 40 works differently.
Who should be careful with higher protein?
If you have kidney disease, check with your doctor first. The PROT-AGE group notes that people with severe kidney disease (eGFR under 30, not on dialysis) may need to limit protein. If you are unsure, bring this article to your appointment alongside our doctor conversation checklist. This is education, not medical advice, and I coach nutrition and training rather than diagnose or prescribe.
Key takeaways
- The RDA (0.8 g/kg) is a minimum, not a goal for women who train.
- A practical starting range after 40 is 1.2 to 1.6 g/kg, or 82 to 109 g for a 150-pound woman.
- Experts such as Sims, Haver and Attia recommend higher ranges for active women; the right number depends on your training, body composition and goals.
- Spread protein across the day: 25 to 40 g per meal beats one big dinner.
- Protein works best alongside heavy, progressive strength training.
FAQ
Is 100 grams of protein a day too much for a woman?
For most healthy women who strength train, 100 grams is within the range experts discuss. It is about 1.5 g/kg for a 150-pound woman. Women with kidney disease should check with their doctor first.
Do I need a protein powder?
No. Food comes first. A powder is a convenient way to close a gap on a busy morning, but you can reach your number with eggs, yogurt, cottage cheese, fish, poultry, tofu and legumes.
Does protein timing matter?
Distribution matters more than a precise clock time. Getting a solid serving at each meal, including breakfast and after training, helps more than saving it all for dinner.
Want your numbers built around your life?
I work privately with women over 40 in Carlsbad, Encinitas, Oceanside and across North County San Diego, and online, to turn numbers like these into a plan that fits your training, schedule and appetite. Apply for private coaching or learn more about me.
Sources: Bauer J, et al. PROT-AGE position paper, J Am Med Dir Assoc 2013;14(8):542-559; Dr. Stacy Sims, Why Women Need to Prioritize Protein; Dr. Stacy Sims, Empowering Female Athletes Part 2; Peter Attia, MD, protein intake; The Pause Life, protein guidance from Dr. Mary Claire Haver.