Project 176223

With more than half of the Canadian population being overweight, the incentive to use high protein diets for weight loss is substantial. However, although the dietary recommendations for Canadians appear to condone high protein diets, the committee that wrote these recommendations stated that more research on the safety of high protein diets is needed. Our previous work suggested that high protein diets have subtle, yet detrimental effects on the normal kidney in the long-term. However, obese individuals already have marginally compromised kidneys and therefore it is likely that high protein diets will have greater effects on these kidneys. High homocysteine levels (an indicator of increased disease risk) in obese individuals also may be worsened further with high protein diets. On the other hand, high protein diets may have beneficial effects on fat tissue, as well as on important health issues related to obesity, including the risk of diabetes and hypertension. The purpose of this study is to examine the effects of high protein diets on health indices in obesity using a rat model. Specific health parameters to be assessed will include effects on the kidney, homocysteine metabolism, blood pressure, blood sugar handling and fat tissue. In addition, this study also will examine the effect of protein type on these health effects. Further, it will examine whether the effects are reversible, and whether the effects are similar in growing animals, since the long-term consequences of a high protein diet during youth are not known. Finally, the effects of high protein diets under caloric restriction also will be examined. These studies will furnish information and biomarkers of health status that will be useful for future studies in humans and that are relevant to the dietary recommendations for protein intake.