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 randomized cross-over trial were instructed to eat an allotted amount of walnuts (28–56g) 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 35g during the walnut-supplemented diet. The walnut-supplemented diet resulted in greater daily energy intake (557kJ (133kcal)), which should theoretically have led to a weight gain of 3·1kg 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/m2), 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/m2). 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 resulted in weight gain much lower than expected and which became non-significant after controlling for differences in energy intake.

Background and aim The effects of analgesic drugs on sleep are poorly understood. We investigated short- and medium-term effects of tramadol on sleep structure.

Methods Eight healthy volunteers received a placebo (predrug placebo-night), then, in a randomized, double-blind, cross-over fashion a single oral dose of tramadol 50 mg or 100mg (drug-night), and finally, again a placebo (postdrug placebo-night). Standardized polysomnography (electroencephalogram, electro-oculogram, submental electromyogram) was continuously recorded during placebo- and drug-nights

Results During drug-nights both doses of tramadol significantly increased the duration of stage 2 sleep, and significantly decreased the duration of slow-wave sleep (stage 4). Tramadol 100mg but not 50 mg significantly decreased the duration of paradoxical (rapid eye movement) sleep. In the placebo-night after tramadol 100mg (but not after 50 mg) duration of stage 2 sleep was significantly shorter, and duration of stage 4 sleep was significantly longer compared with the predrug placebo-night. Conclusion In healthy volunteers, a single dose of tramadol 50 mg disturbs sleep in the night of drug application. With 100mg, sleep is disturbed in both the night of drug application and in the subsequent night.