Overall , high-walnut-enriched diets significantly decreased total and LDL cholesterol for the duration of the short-term trials .
BACKGROUND Consumption of nuts has been associated with a decreased risk of  cardiovascular disease events  and death .
Walnuts in particular have a unique profile : they are rich in polyunsaturated fatty acids , which may improve blood lipids and other cardiovascular disease risk factors .
OBJECTIVES We aim ed to conduct a literature review and a meta- analysis to combine the results from several trials and to estimate the effect of walnuts on blood lipids .
Does regular walnut consumption lead to weight gain?
Studies consistently show the beneficial effects of eating nuts , but as high-energy foods , their regular consumption may lead to weight gain . We tested if daily consumption of walnuts ( approximately 12 % energy intake ) for 6 months would modify body weight and body composition in free-living subjects . Ninety participants in a 12-month r and omized cross-over trial were instructed to eat an allotted amount of walnuts ( 28 - 56 g ) during the walnut-supplemented diet and not to eat them during the control diet , with no further instruction . Subjects were unaware that body weight was the main outcome . Dietary compliance was about 95 % and mean daily walnut consumption was 35 g during the walnut-supplemented diet . The walnut-supplemented diet result ed in greater daily energy intake ( 557 kJ ( 133 kcal ) ) , which should theoretically have led to a weight gain of 3.1 kg over the 6-month period . For all participants , walnut supplementation increased weight ( 0.4 ( se 0.1 ) kg ) , BMI ( 0.2 ( se 0.1 ) kg/m(2 ) ) , fat mass ( 0.2 ( se 0.1 ) kg ) and lean mass ( 0.2 ( se 0.1 ) kg ) . But , after adjusting for energy differences between the control and walnut-supplemented diets , no significant differences were observed in body weight or body composition parameters , except for BMI ( 0.1 ( se 0.1 ) kg/m(2 ) ) . The weight gain from incorporating walnuts into the diet ( control-->walnut sequence ) was less than the weight loss from withdrawing walnuts from the diet ( walnut-->control sequence ) . Our findings show that regular walnut intake result ed in weight gain much lower than expected and which became non-significant after controlling for differences in energy intake
Overall , high-walnut-enriched diets significantly decreased total and LDL cholesterol for the duration of the short-term trials .
BACKGROUND Consumption of nuts has been associated with a decreased risk of  cardiovascular disease events  and death .
Walnuts in particular have a unique profile : they are rich in polyunsaturated fatty acids , which may improve blood lipids and other cardiovascular disease risk factors .
OBJECTIVES We aim ed to conduct a literature review and a meta- analysis to combine the results from several trials and to estimate the effect of walnuts on blood lipids .