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 .
Long-term effects of a high-protein, low-carbohydrate diet on weight control and cardiovascular risk markers in obese hyperinsulinemic subjects
OBJECTIVE : To compare the long-term compliance and effects of two low-fat diets differing in carbohydrate to protein ratio on body composition and biomarkers of cardiovascular disease risk in obese subjects with hyperinsulinemia . DESIGN : Outpatient , parallel , clinical intervention study of two groups of subjects r and omly assigned to either a st and ard protein ( SP ; 15 % protein , 55 % carbohydrate ) or high-protein ( HP ; 30 % protein , 40 % carbohydrate ) diet , during 12 weeks of energy restriction ( ∼6.5 MJ/day ) and 4 weeks of energy balance ( ∼8.3 MJ/day ) . Subsequently , subjects were asked to maintain the same dietary pattern for the succeeding 52 weeks with minimal professional support . SUBJECTS : A total of 58 obese , nondietetic subjects with hyperinsulinemia ( 13 males/45 females , mean age 50.2 y , mean body mass index ( BMI ) 34.0 kg/m2 , mean fasting insulin 17.8 mU/l ) participated in the study .  MEASUREMENTS : Body composition , blood pressure , blood lipids , fasting glucose , insulin , CRP and sICAM-1 were measured at baseline and at weeks 16 and 68 . Urinary urea/creatinine ratio was measured at baseline , week 16 and at 3 monthly intervals thereafter . RESULTS : In total , 43 subjects completed the study with similar dropouts in each group ( P=0.76 ) . At week 68 , there was net weight loss ( SP −2.9±3.6 % , HP −4.1±5.8 % ; P<0.01 ) due entirely to fat loss ( P<0.001 ) with no diet effect . Both diets significantly increased HDL cholesterol concentrations ( P<0.001 ) and decreased fasting insulin , insulin resistance , sICAM-1 and CRP levels ( P<0.05 ) . Protein intake was significantly greater in HP during the initial 16 weeks ( P<0.001 ) , but decreased in HP and increased in SP during 52-week follow-up , with no difference between groups at week 68 , indicating poor long-term dietary adherence behaviour to both dietary patterns . CONCLUSION : Without active ongoing dietary advice , adherence to dietary intervention is poor . Nonetheless , both dietary patterns achieved net weight loss and improvements in cardiovascular risk factors
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 .