Adverse gastrointestinal events were more common with high-protein diets .
Multivariable meta-regression analysis showed no significant dose response with higher protein intake .
Conclusions : Higher-protein diets  probably improve adiposity , blood pressure and triglyceride levels , but these effects are small and need to be weighed against the potential for harms
Background / Objectives : Numerous r and omised controlled trials ( RCTs ) published in first tier medical journals have evaluated the health effects of diets high in protein .
We conducted a rigorous systematic review of RCTs comparing higher- and lower-protein diets .
Macronutrient intake, plasma large neutral amino acids and mood during weight-reducing diets
Influence of diet composition on mood during weight-reducing diets was studied in healthy young women of normal weight . A broad range of macronutrient intake was achieved by means of divergent dietary instructions for the composition of a 1,000 kcal per day diet adhered to for six weeks . Global mood during the last three weeks of the diet was significantly better in the “ vegetarian ” than in the “ mixed ” diet group . During this time a significant correlation was observed between relative carbohydrate intake and global mood ( r=−0.74 ; p<0.01 ) and between the ratio of plasma tryptophan to other large neutral amino acids ( a predictor of tryptophan flow into brain ) and global mood ( r=− 0.52 ; p<0.05 ) . Results suggest that group differences are related to differences in carbohydrate intake . It is hypothesized that impairment of central serotonergic function due to reduced tryptophan availability can prompt mood deterioration in situations of relatively low carbohydrate intake
Adverse gastrointestinal events were more common with high-protein diets .
Multivariable meta-regression analysis showed no significant dose response with higher protein intake .
Conclusions : Higher-protein diets  probably improve adiposity , blood pressure and triglyceride levels , but these effects are small and need to be weighed against the potential for harms
Background / Objectives : Numerous r and omised controlled trials ( RCTs ) published in first tier medical journals have evaluated the health effects of diets high in protein .
We conducted a rigorous systematic review of RCTs comparing higher- and lower-protein diets .