More Protein = More Fat Loss?

As a registered dietitian, it is my job to translate nutrition science into practical strategies for you to use in achieving your health and fitness goals. One of the most common goals I encounter is weight loss or more specifically fat loss. The ultimate goal for most individuals is to lost fat and gain muscle. Recently, a study done from McMaster University investigated the role of varying protein intakes and their effects on weight loss and body composition. Below you will find a breakdown of what they did, what the results were, and how to apply it to your current diet protocol.

Study Design

40 overweight men with an average age of 23, BMI of 29.7, and 24.2% body fat were studied for 4 weeks. All participants had a history of physical activity 1-2x per week but did not engage in regular resistance training. Participants were then split into 1 of 2 groups. Both groups had an calorie deficit of 40% but one group (control) consumed 1.2 g of protein per kilogram and the higher group had 2.4 g of protein per kilogram. On top of the diet protocol, both groups engaged in 6 days a week of rigorous exercise that included 2 days of full body resistance training, 1 day of plyometric training, 2 days of high intensity interval training, and one day of cycling. They then measured body composition, strength and aerobic capacity, and certain blood markers before and after the intervention.

What did they find?

Both groups lost the same amount of weight (about 3.5 kg) without any significant differences between the two groups. The main difference came in lean body mass. The control group maintained their lean body mass with no significant differences while the high protein group gained 1.2 kg of lean body mass. This would bring the actual fat loss to 4.8 kg compared to 3.5 kg in the control group. The rest of the performance measures were similar between the two groups with no significant differences.

How can we apply these results to your nutrition strategy?

The results of this study are very promising. It did a great job of showing that fat loss and lean mass gain can happen at the same time which was believed to be very challenging. This study highlights the importance of higher protein intakes than the RDA (0.8g/kg) and the importance of resistance training when trying to improve body composition. Several other studies have reported similar findings that increased protein intakes lead to more favorable body composition changes. While I would typically recommend not going for a 40% calorie deficit like this study, I would recommend aiming for at least 1.6 g/kg-2.0 g/kg or an easier way to think would be to aim for at least 30 g of protein with each meal.

For more information or a more personalized nutrition plan, feel free to contact our dietitian today!



Longland, T. M., Oikawa, S. Y., Mitchell, C. J., Devries, M. C., & Phillips, S. M. (2016). Higher compared with lower dietary protein during an energy deficit combined with intense exercise promotes greater lean mass gain and fat mass loss: a randomized trial. American Journal of Clinical Nutrition, 103(3), 738-746. doi:10.3945/ajcn.115.119339
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Written by: Jesus Hernandez RDN, LD

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