No significant differences were observed for weight , waist circumference , fat mass , blood lipids ( i.e. total cholesterol , LDL-cholesterol , HDL-cholesterol , triacylglycerols ) , C-reactive protein , diastolic and systolic blood pressure , fasting glucose and glycosylated hemoglobin .
Sensitivity analysis of high quality RCTs confirmed the data of the primary analyses , while exclusion of studies with diabetic subjects result ed in an additional benefit of high-protein diets with respect to a more marked increase in HDL-cholesterol .
Conclusion According to the present meta- analysis of long-term RCTs , high-protein diets exerted neither specific beneficial nor detrimental effects on outcome markers of obesity , cardiovascular disease or glycemic control .
Background Meta-analyses of short-term studies indicate favorable effects of higher protein vs. lower protein diets on health outcomes like adiposity or cardiovascular risk factors , but their long-term effects are unknown .
The effect of high-protein, low-carbohydrate diets in the treatment of type 2 diabetes: a 12 month randomised controlled trial
Aims /hypothesisShort-term dietary studies suggest that high-protein diets can enhance weight loss and improve glycaemic control in people with type 2 diabetes . However , the long-term effects of such diets are unknown . The aim of this study was to determine whether high-protein diets are superior to high-carbohydrate diets for improving glycaemic control in individuals with type 2 diabetes . Methods Overweight/obese individuals ( BMI 27–40 kg/m2 ) with type 2 diabetes ( HbA1c 6.5–10 % ) were recruited for a 12 month , parallel design , dietary intervention trial conducted at a diabetes specialist clinic ( Melbourne , VIC , Australia ) . Of the 108 initially r and omised , 99 received advice  to follow low-fat ( 30 % total energy ) diets that were either high in protein ( 30 % total energy , n = 53 ) or high in carbohydrate ( 55 % total energy , n = 46 ) . Dietary assignment was done by a third party using computer-generated r and om numbers . The primary endpoint was change in HbA1c . Secondary endpoints included changes in weight , lipids , blood pressure , renal function and calcium loss . Study endpoints were assessed blinded to the diet group , but the statistical analysis was performed unblinded . This study used an intention-to-treat model for all participants who received dietary advice . Follow-up visits were encouraged regardless of dietary adherence and last measurements were carried forward for study non-completers . Results Ninety-nine individuals were included in the analysis ( 53 in high protein group , 46 in high carbohydrate group ) . HbA1c decreased in both groups over time , with no significant difference between groups ( mean difference of the change at 12 months ; 0.04 [ 95 % CI −0.37 , 0.46 ] ; p = 0.44 ) . Both groups also demonstrated decreases over time in weight , serum triacylglycerol and total cholesterol , and increases in HDL-cholesterol . No differences in blood pressure , renal function or calcium loss were seen . Conclusions /interpretationThese results suggest that there is no superior long-term metabolic benefit of a high-protein diet over a high-carbohydrate in the management of type 2 diabetes . Trial registration ACTRN12605000063617 ( www.anzctr.org.au ) . Funding This study was funded by a nutritional research grant from Meat and Livestock Australia ( MLA ) . J.E. Shaw is supported by NHMRC Fellowship 586623
No significant differences were observed for weight , waist circumference , fat mass , blood lipids ( i.e. total cholesterol , LDL-cholesterol , HDL-cholesterol , triacylglycerols ) , C-reactive protein , diastolic and systolic blood pressure , fasting glucose and glycosylated hemoglobin .
Sensitivity analysis of high quality RCTs confirmed the data of the primary analyses , while exclusion of studies with diabetic subjects result ed in an additional benefit of high-protein diets with respect to a more marked increase in HDL-cholesterol .
Conclusion According to the present meta- analysis of long-term RCTs , high-protein diets exerted neither specific beneficial nor detrimental effects on outcome markers of obesity , cardiovascular disease or glycemic control .
Background Meta-analyses of short-term studies indicate favorable effects of higher protein vs. lower protein diets on health outcomes like adiposity or cardiovascular risk factors , but their long-term effects are unknown .