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 .
Low-Carbohydrate Diets and All-Cause and Cause-Specific Mortality
BACKGROUND Data on the long-term association between low-carbohydrate diets and mortality are sparse . OBJECTIVE To examine the association of low-carbohydrate diets with mortality during 26 years of follow-up in women and 20 years in men . DESIGN Prospect i ve cohort study of women and men who were followed from 1980 ( women ) or 1986 ( men ) until 2006 .  Low-carbohydrate diets , either animal-based ( emphasizing animal sources of fat and protein ) or vegetable-based ( emphasizing vegetable sources of fat and protein ) , were computed from several vali date d food-frequency question naires assessed during follow-up . SETTING Nurses ' Health Study and Health Professionals ' Follow-up Study . PARTICIPANTS 85 168 women ( aged 34 to 59 years at baseline ) and 44 548 men ( aged 40 to 75 years at baseline ) without heart disease , cancer , or diabetes . MEASUREMENTS Investigators documented 12 555 deaths ( 2458 cardiovascular-related and 5780 cancer-related ) in women and 8678 deaths ( 2746 cardiovascular-related and 2960 cancer-related ) in men . RESULTS The overall low-carbohydrate score was associated with a modest increase in overall mortality in a pooled analysis ( hazard ratio [ HR ] comparing extreme deciles , 1.12 [ 95 % CI , 1.01 to 1.24 ] ; P for trend = 0.136 ) . The animal low-carbohydrate score was associated with higher all-cause mortality ( pooled HR comparing extreme deciles , 1.23 [ CI , 1.11 to 1.37 ] ; P for trend = 0.051 ) , cardiovascular mortality ( corresponding HR , 1.14 [ CI , 1.01 to 1.29 ] ; P for trend = 0.029 ) , and cancer mortality ( corresponding HR , 1.28 [ CI , 1.02 to 1.60 ] ; P for trend = 0.089 ) . In contrast , a higher vegetable low-carbohydrate score was associated with lower all-cause mortality ( HR , 0.80 [ CI , 0.75 to 0.85 ] ; P for trend < /= 0.001 ) and cardiovascular mortality ( HR , 0.77 [ CI , 0.68 to 0.87 ] ; P for trend < 0.001 ) . LIMITATIONS Diet and lifestyle characteristics were assessed with some degree of error . Sensitivity analyses indicated that results were probably not substantively affected by residual confounding or an unmeasured confounder . Participants were not a representative sample of the U.S. population . CONCLUSION A low-carbohydrate diet based on animal sources was associated with higher all-cause mortality in both men and women , whereas a vegetable-based low-carbohydrate diet was associated with lower all-cause and cardiovascular disease mortality rates . PRIMARY FUNDING SOURCE National Institutes of Health
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 .