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 Diabetes Excess Weight Loss (DEWL) Trial: a randomised controlled trial of high-protein versus high-carbohydrate diets over 2 years in type 2 diabetes
Aims /hypothesisTo compare the effectiveness of low-fat high-protein and low-fat high-carbohydrate dietary advice on weight loss , using group-based interventions , among overweight people with type 2 diabetes . Study design Multicentre parallel ( 1:1 ) design , blinded r and omised controlled trial . Methods Individuals with type 2 diabetes aged 30–75 years and a BMI > 27 kg/m2 were r and omised , by an independent statistician using sequentially numbered sealed envelopes , to be prescribed either a low-fat high-protein ( 30 % of energy as protein , 40 % as carbohydrate , 30 % as fat ) or a low-fat high-carbohydrate ( 15 % of energy as protein , 55 % as carbohydrate , 30 % as fat ) diet . Participants attended 18 group sessions over 12 months . Primary outcomes were change in weight and waist circumference assessed at baseline , 6 and 12 months . Secondary outcomes were body fatness , glycaemic control , lipid profile , blood pressure and renal function . A further assessment was undertaken 12 months after the intervention . Research assessors remained blinded to group allocation throughout . Intention-to-treat analysis was performed . Results A total of 419 participants were enrolled ( mean ± SD age 58 ± 9.5 years , BMI 36.6 ± 6.5 kg/m2 and HbA1c 8.1 ± 1.2 % ( 65 mmol/mol ) ) . The study was completed by 70 % ( 294/419 ) . No differences between groups were found in change in weight or waist circumference during the intervention phase or the 12-month follow-up . Both groups had lost weight ( 2–3 kg , p < 0.001 ) and reduced their waist circumference ( 2–3 cm , p < 0.001 ) by 12 months and largely maintained this weight loss for the following 12 months . By 6 months , the difference in self-reported dietary protein between groups was small ( 1.1 % total energy ; p < 0.001 ) . No significant differences between groups were found in secondary outcomes : body fatness , HbA1c , lipids , blood pressure and renal function . There were no important adverse effects . Conclusions /interpretationIn a ‘ real-world ’ setting , prescription of an energy-reduced low-fat diet , with either increased protein or carbohydrate , results in similar modest losses in weight and waist circumference over 2 years . Trial registration : Australia New Zeal and Clinical Trials Register ACTRN12606000490572 Funding : The Health Research Council of New Zeal and ( 06/337 )
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 .