Protein supplementation and weight loss
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Protein Supplementation and Weight Loss: Effects on Body Weight and Body Composition
Research shows that increasing protein intake during weight loss can help reduce body weight and fat mass, while also preserving muscle mass or fat-free mass in both general and specific populations, such as older adults and those who have undergone bariatric surgery Gomes2017Moon2020Leidy2015+4 MORE. Several studies and meta-analyses report that higher-protein diets or protein supplementation, especially when combined with calorie restriction and exercise, lead to greater fat loss and better maintenance of muscle mass compared to lower-protein diets Gomes2017Moon2020Leidy2015+4 MORE. This effect is partly due to increased satiety, higher energy expenditure, and the preservation of resting energy expenditure during weight loss Moon2020Leidy2015Westerterp-Plantenga2009.
In people who have regained weight after bariatric surgery, whey protein supplementation has been shown to promote additional weight and fat mass loss without reducing fat-free mass . Meta-analyses also confirm that protein supplementation after bariatric surgery can improve weight loss and some body composition measures, though it may not significantly change BMI or overall lean body mass .
Protein Supplementation and Weight Maintenance
Protein supplementation may also help limit weight regain after initial weight loss. Studies indicate that adding extra protein to the diet during weight maintenance phases results in less weight regain, improved body composition, and increased satiety compared to control groups Moon2020Lejeune2005. This suggests that higher protein intake can be beneficial not only for losing weight but also for keeping it off.
Protein Supplementation and Glucose Homeostasis
While protein supplementation supports muscle preservation and fat loss, some studies in older adults and postmenopausal women with obesity have found that it may reduce the positive effects of weight loss on glucose metabolism and insulin sensitivity Batsis2022Batsis2023Smith2016. Specifically, protein supplementation during weight loss led to a smaller decrease in insulin resistance and less improvement in glucose homeostasis compared to non-protein groups Batsis2022Batsis2023Smith2016. This effect was observed even though both groups lost weight, suggesting that the macronutrient composition of a weight loss diet can influence metabolic outcomes beyond weight loss alone.
Safety and Other Health Considerations
Most studies report that higher-protein diets do not have adverse effects on bone health or kidney function in healthy adults Moon2020Westerterp-Plantenga2009. In fact, protein intake may help increase bone mineral mass and reduce the risk of osteoporotic fractures, especially during weight loss .
Conclusion
Protein supplementation during weight loss can enhance fat loss, help preserve muscle mass, and support weight maintenance. However, it may also reduce some of the metabolic benefits of weight loss, particularly improvements in glucose homeostasis and insulin sensitivity, especially in older adults and postmenopausal women with obesity. Overall, higher-protein diets are effective and generally safe for weight management, but the specific benefits and potential drawbacks should be considered based on individual health goals and metabolic risk factors.
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