If you're an untrained adult with extra weight, doing strength training for 12 weeks while eating less and getting enough protein (at least 1.4g per kg of body weight) can improve your muscle quality. This improvement shows up as cleaner-looking muscles on an ultrasound, and it doesn’t matter whether you cut calories every day or just on two days a week.

What we've found so far is that combining resistance training, high protein intake, and energy restriction may improve muscle quality in untrained adults with overweight or obesity. The evidence we’ve reviewed leans toward this approach being beneficial, regardless of whether calorie reduction happens daily or just two days a week. Our analysis of the available research shows that when untrained adults with extra weight do resistance training for 12 weeks while eating fewer calories and consuming at least 1.4 grams of protein per kilogram of body weight, muscle quality can improve [1]. This change appears as cleaner, more defined muscle structure on ultrasound imaging, which is one way we assess muscle health. We don’t yet know how this might differ over longer periods or in trained individuals, but in the short term, the results are consistent across the studies we’ve examined. We also looked at whether 5:2 intermittent fasting—eating very few calories on two days of the week—works better than cutting calories every day. Based on what we've reviewed so far, there’s no clear difference between the two approaches when combined with resistance training and adequate protein [1]. Both methods support improvements in muscle quality, so the choice may come down to personal preference. It’s important to note that all the supporting evidence comes from studies focused on untrained individuals over a 12-week period. We don’t have enough data to say how these findings might apply to other groups or longer timelines. Practical takeaway: If you’re new to strength training and want to improve your muscle health while losing weight, lifting weights, eating enough protein, and reducing calories—even just a couple days a week—could help.