From hormones and enzymes to muscles and the immune system, every cell in your body contains protein. That's why it's so important to get enough in your diet! The recommended dietary allowance (RDA) for protein is 0.8 grams per kilogram of body weight, or about 0.36 grams per pound. If you lift weights regularly, however, you can throw that RDA right out the window.
Your body needs more protein to enhance recovery from training and support muscle growth and maintenance. The problem is that "more protein" isn't exactly specific. For a long time, active women have been guessing as to the amount of protein they need to sculpt and maintain a lean, strong body.
But the days of guesswork are coming to an end! My research team and I at The Performance & Physique Enhancement Laboratory at the University of South Florida have been studying how varying amounts of protein in the diet influence body composition in resistance-trained women.[1] Here's what we found, and how you can put it into practice!
The Study Details
In our study, two groups of women completed a strength-training plan—a periodized resistance-training program, to be specific—lasting eight weeks. The program consisted of two upper-body training days and two lower-body training days per week. One group ate a high-protein diet; the other group ate a lower-protein diet.
The high-protein group was instructed to eat 1.1 grams of protein per pound of body weight, including 25 grams of Dymatize ISO-100 whey protein before and after each training session. The lower-protein group was told to eat 0.55 grams of protein per pound of body weight, including only 5 grams of Dymatize ISO-100 whey protein immediately pre- and post-workout.
Each participant was encouraged to consume the specific amount of protein each day, but they were allowed to eat as many (or as few) carbohydrates and fats as they wanted.
At the end of the study, the women who followed a higher-protein diet gained significantly more lean body mass (4.6 pounds) compared to the lower-protein group (1.5 pounds). The higher protein group also lost more body fat than the lower-protein group, although this change did not reach statistical significance.
The Power of Protein
These results may not seem earth-shattering, but they do confirm what you probably already know: If women, especially those who train intensely, eat a higher-protein diet, it's likely they'll gain more muscle than women who eat a lower-protein diet.
Here's what is surprising, though: The women in the higher-protein group consumed on average an additional 423 additional calories from protein every day! We could easily assume that anyone consuming an extra 400-500 calories a day for eight weeks would gain body fat, but that's not what happened in this study.
The women on the higher-protein diet actually lost more body fat than women on the lower-protein diet, even though they consumed more calories! Specifically, the higher-protein group lost 2.4 pounds of fat mass, compared to only 1.7 pounds in the lower-protein group, by eating more calories from protein.
This was the first study to use only resistance-trained women; however, we've seen similar outcomes in previous studies that have used only men or a combination of both men and women. Research out of Nova Southeastern University has shown that consuming an extra 500-750 calories a day from protein—primarily from MusclePharm Combat Powder, in this case—while following a resistance-training program does not lead to body-fat gains [2,3]. Unlike the current study, however, participants who consumed higher amounts of protein did not observe significant changes in lean body mass or fat loss.
In light of our findings when studying women only, it may be that women are actually more responsive to higher daily protein intakes for increasing lean body mass than men are. However, this is just a theory, and we need to conduct much more research before we can say anything with certainty.
Don't Just Watch the Scale
You've probably heard "Don't worry about what the scale says" hundreds of times, and now you have good reason to heed that advice! If we had only measured body weight in our recent study, the women in the higher-protein group would have seen that they actually gained just over 2 pounds. I don't need to tell you how devastating this can feel.
Like good scientists, however, we evaluated body composition, not just body weight, and we found that the higher-protein group gained more muscle and lost more fat than the lower-protein group—results they wouldn't know just by stepping on the scale.
Rather than focusing on one number, keep track of the changes in your body-fat loss and muscle gain. If you notice your weight going up and your body-fat percentage going down, you know you're doing something right!
I also recommend taking progress pictures, paying attention to how your clothes fit, and monitoring your energy levels in the gym. Positive changes in all of these aspects can suggest your diet and training program are working!
The Final Word
If your goal is to gain lean body mass and drop some body fat, there's a clear advantage to following a higher-protein diet while engaging in a resistance-training program. My team at USF and I recommend that women eat roughly 1 gram of high-quality protein per pound of body weight daily to improve body composition and maximize recovery. So, drop that salad fork and pick up a shaker cup—or at least add some chicken to the salad!
References
- Campbell B, Aguilar D, Vargas A, Conlin A, Sanders A, Fink-Irizarry P, Norton L, Perry R, McCallum R, Wynn MR, and Lenton J. Effects of a high (2.4 g/kg) vs. low/moderate (1.2 g/kg) protein intake on body composition in aspiring female physique athletes engaging in an 8-week resistance training program. Presented at the 2016 International Society of Sports Nutrition Annual Conference, Clearwater, Florida, June 2016.
- Antonio J, Peacock C.A., Ellerbroek A., Fromhoff B., Silver T. (2014) The effects of consuming a high protein diet (4.4 g/kg/d) on body composition in resistance-trained individuals. Journal of the International Society of Sports Nutrition, 12(39).
- Antonio, J., Ellerbroek, A., Silver, T., Orris, S., Scheiner, M., Gonzalez, A., & Peacock, C.A. (2015). A high protein diet (3.4 g/kg/d) combined with a heavy resistance training program improves body composition in healthy trained men and women-a follow-up investigation. Journal of the International Society of Sports Nutrition, 12(1), 1.