A Diet High in Protein Reduces Weight Gain, Food Intake and Liver Weight in Obese Zucker Rats

Abstract

It has become a challenge to find effective treatments and preventive strategies to reduce obesity and diabetes (T2DM). There are several approaches to treating these diseases, including nutrition therapy. Diets high in protein are linked with weight reduction and improved insulin resistance. Therefore, the objective of this study was to examine the effects of a long‐term, high protein (pro) diet (40%) vs a moderate pro diet (20%) on body composition and metabolism using a genetic model of obesity/T2DM. Male, lean (L) and obese (O) Zucker rats (n = 8‐10 per group) were housed 2/cage and placed in one of four groups: L20, L40, O20 or O40. Animals were provided ad libitum access to diet and water for 12 weeks. At 12 weeks, animals were fasted for 8 hours, then trunk blood and tissues were collected. L had lower food intake (P < 0.05) than O, and O40 had significantly lower food intake (P < 0.05) than O20. Animals fed 40% pro had significantly lower weight gain (P < 0.05) than those fed 20% pro. L had more muscle mass and lower fat mass than O (P < 0.05). However, L40 had significantly lower fat mass than L20. O40 had lower liver weights (P < 0.05) than O20. There was no difference in fasting glucose and O had higher fasting insulin. Fasting free fatty acids were higher in animals fed the 20% pro diet. There was no difference in basal phosphorylation of Akt, AMPK, mTOR or 4E‐BP1. There was no difference in basal BCAA between L20 and O20. L40 and O40 had significantly higher basal levels of BCAA (P < 0.05). We conclude that higher protein diets have the potential to reduce weight gain and alter metabolism in obese rats. Funded by Arkansas Biosciences Institute.