The Effect of Increased Dietary Protein on Body Protein Breakdown and Anabolic Sensitivity of Bone and Skeletal Muscle during Calorie-Restricted Weight Loss

Abstract: Calorie-restricted weight loss is typically not only associated with a desired loss of body fat, but also with the loss of lean mass. This lean mass loss, which primarily occurs in skeletal muscle, is concomitant with a measurable reduction in metabolic rate and a suppression of anabolic hormones that play a key role in the maintenance of skeletal muscle and bone health. In order to prevent these detrimental effects of weight loss, which can be associated with an increased propensity of weight regain, loss of functional capacity, and an increased risk of osteoporosis later in life, strategies are needed that attenuate the concomitant metabolic adaptations and preserve lean mass and bone. Previous studies have shown that a high dietary protein intake can reduce the loss of lean mass during caloric restriction. However, the underlying mechanisms remain poorly understood, and more importantly, it remains unknown whether increased protein intake can preserved the anabolic sensitivity of bone and skeletal muscle tissue. Therefore, our goal is to conduct a randomized controlled trial to establish the effects of increased dietary protein during calorie restriction on metabolism, anabolic hormone secretion, and biomarkers of bone turnover. We will further utilize novel stable nitrogen isotope technology to quantify the effects of increased protein on body protein breakdown. The objective of this planning proposal is to strengthen a federal grant application through providing pilot data and the framework and expertise for the collaborative use of innovate nitrogen isotope methodology.

Funding: NU Foundation Layman Grants