A Cross-Sectional Study on the Association of Walnut Consumption with Obesity and Relative Fat Mass among United States Adolescents and Young Adults in NHANES (2003-2020).

Background: Walnuts contain nutrients and phytochemicals that can promote metabolic health. However, the high energy content of walnuts along with other nuts raises the concern that consuming nuts promotes obesity.

Objectives: We sought to investigate the associations between consumption of walnuts as well as other nuts and measures of obesity in adolescents and young adults.

Methods: This study included 8874 adolescents (12-19 y) and 10,323 young adults (20-39 y) from 8 waves of National Health and Nutrition Examination Survey data (2003-2020). The associations of consumption of ) walnuts only (WO); ) walnuts with other nuts (WON); ) other nuts (ON); and ) no nuts (NN) with obesity status and relative fat mass (RFM) were assessed using logistic and linear regressions stratified by age group and sex. Sample weights were used in all statistical analyses.

Results: The mean daily intake of walnuts was not different between the 2 walnut consumption groups within each age group (adolescents: 2.18 [standard error (SE) 0.14] g; = 0.917; young adults: 4.23 [0.37] g; = 0.682). The WON group had the lowest prevalence of obesity (adolescents: 8.3%; young adults: 21.1%) while the NN group had the highest prevalence (adolescents: 24.1%; young adults: 35.4%). The models indicated lower odds of obesity in adolescent girls (odds ratio [OR]: 0.27; < 0.05) and young adult women (OR: 0.58; < 0.05) who consumed WON than in those who consumed NN. In both young women and girls, RFM was significantly lower in the WON and ON groups than the NN group ( < 0.001). In young men, WON consumption was also associated with a lower RFM (OR: -1.24; 95% confidence interval: -2.21, -0.28) compared with NN consumption.

Conclusions: For adolescents girls and young women, dietary intake of walnuts combined with other nuts has the strongest inverse association with measures of obesity.