Title: Long term effects of walnut supplementation on body weight and diet patterns

Summary:
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 (28–56 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 resulted 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/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.

Publications:
Sabaté J, Cordero-MacIntyre Z, Siapco G, Torabian S, Haddad E, . Does regular walnut consumption lead to weight gain? Br J Nutr 2005, 94:859-864. Full Text

Presentations:
Torabian Esfahani, S, Haddad, E, Tanzman, JS, Cordero-MacIntyre, Z, Fernandez, ML, Vega-Lopez, S, Zern, T, Sabaté, J. The Long Term Effects of Walnut Consumption on the Blood Lipid Components. XIVth International Congress of Dietetics, Chicago, IL, May 2004. abstract

Cordero-MacIntyre, Z, Tanzman, JS, Torabian Esfahani, S, Fernandez, ML, Sabaté, J. Daily Walnut Supplementation Impacts Blood Glucose Levels and Body Fat. Experimental Biology 2004, Washington, DC., April 2004. abstract

Torabian Esfahani, S, Siapco, GS, Haddad E, Tanzman, J, Cordero-MacIntyre, Z, Sabaté, J. Walnuts Lower Serum Total Cholesterol in Hypercholesterolemic Subjects. Nutrition Week Conference, Las Vegas, NV, February 2004. abstract

Siapco, GS, Torabian Esfahani, S, Haddad, E, Cordero-MacIntyre, Z, Sabaté, J. Regular Walnut Consumption Increases Omega-3 gatty Acids in Erythrocyte Membranes. Nutrition Week Conference, Las Vegas, NV, February 2004. abstract

Cordero-MacIntyre, Z, Torabian, S, Metghalchi, S, Burns-Whitmore, B, Grakov, S, Sabaté, J. Impact of Walnut Consumption on Body Composition. Experimental Biology 2003, San Diego, CA, April 2003. abstract

Date: 2000

Funded by: The California Walnut Commission