What is the relationship between snacking and body weight in adults?

Limited and inconsistent evidence suggests that snacking is associated with increased body weight.

Evidence Summary Overview

The literature review identified two prospective cohort studies (Halkjaer, 2009; Woo, 2008). The studies were conducted in Sweden and Hong Kong. Studies ranged in sample size from 1,010 (Woo, 2008) to 22,570 (Halkjaer, 2009). In the study of Halkjaer et al, (2009), diets high in snack food were associated with increased waist circumference over the five-year follow up period. Increased variety of snack food was associated with increased weight gain over a five- to nine-year follow-up period in the study of Woo et al, (2008).

The Committee did not review the literature on the use of snacking as a tool for adults actively losing weight.

Evidence summary paragraphs:

Cohort Studies (2)

Halkjaer J et al, 2009 (positive quality) conducted a prospective cohort study in Denmark to investigate the association between intake from 21 food and beverage groups and the subsequent five-year difference in waist circumference (WC). Data were from the Danish diet, Cancer, and Health Study. Subjects were enrolled from 1993 to 1997, and follow-up occurred five years later, from 1999 to 2002. Baseline weight, height and WC were measured by study personnel, and follow-up measurements were self-reported by subjects. Dietary intake was assessed at baseline using a 192-item, semi-quantitative food frequency questionnaire (FFQ). The final sample included 22,570 women (mean age at baseline was 56 years; mean BMI at baseline was 25kg/m²) and 20,126 men (mean age at baseline was 55 years; mean BMI at baseline was 26kg/m²). The five-year difference in WC was positively associated with energy intake from snack foods for women (0.06, 95% CI: 0.003 to 0.11) and men (0.09, 95% CI: 0.05 to 0.13) (P<0.05). The authors concluded that a diet high in snack foods is associated with larger WC gain in women and men.

Woo J et al, 2008 (positive quality) conducted a prospective cohort study in Hong Kong to examine dietary factors associated with overweight and obesity. Subjects were recruited in 1995 and 1996 and were followed for five to nine years. Height and weight were measured, and BMI was calculated. Dietary assessment was done via a FFQ at baseline. The final sample included 1,010 subjects (mean age, 46 years). Increased variety of snack consumption was associated with increased risk of developing overweight over the five- to nine-year follow-up period (OR 1.45, 95% CI: 1.06 to 1.98, P<0.05). The authors concluded that increase variety of snack consumption may predispose adults to weight gain over a five- to nine-year period.