Abstract 4096: Enhanced Response of Lipid Risk Factors to Increasing Dietary Protein in Overweight or Obese People: Results of the OmniHeart Trial
In the OmniHeart trial, decreasing carbohydrate and replacing it with either protein or unsaturated fat improved lipid risk factors. OmniHeart was a 3-period crossover feeding study (n=164) that compared 3 diets sharing beneficial characteristics of the DASH diet, e.g. low in saturated fat, and high in fruits, vegetables, nuts and fiber. Each period lasted 6 weeks. Weight was held constant. The diets were
high carbohydrate (CARB: 58% carb, 15% prot, 27% fat),
high protein (PROT: 48% carb, 25% prot, 27% fat),
high unsaturated fat (UNSAT: 48% carb, 15% prot, 37% fat [84% unsaturated]).
As previously reported, PROT and UNSAT compared to CARB lowered non-HDL cholesterol and triglycerides (TG); PROT lowered LDL cholesterol whereas UNSAT raised HDL cholesterol. The influences of BMI and other participant characteristics were studied in multiple regression analysis with simultaneous adjustment. Mean (SD) BMI was 30±6. A high BMI enhanced the effects of PROT on non-HDL cholesterol and TG. For each 1 BMI unit increase, the fall in nonHDL cholesterol from PROT was greater by 0.8 mg/dl (0.6% of level on CARB, P=0.008), and the fall in TG was greater by 2.1 mg/dl (2.1% of level on CARB, P=0.01); see figure⇓ for results in BMI tertiles. Results were similar for LDL although not significant. The results were similar for the effects of PROT replacing UNSAT. These findings suggest that in the context of a healthy dietary pattern, partially replacing carbohydrate or unsaturated fat with protein may be especially beneficial to reduce non-HDL cholesterol and TG in overweight or obese adults.