Changes in water and beverage intake and long-term weight changes: results from three prospective cohort studies

Abstract

Objective: To examine the long-term relationship between changes in water and beverage intake and weight change.

Subjects: Prospective cohort studies of 50013 women aged 40-64 years in the Nurses' Health Study (NHS, 1986-2006), 52987 women aged 27-44 years in the NHS II (1991-2007) and 21988 men aged 40-64 years in the Health Professionals Follow-up Study (1986-2006) without obesity and chronic diseases at baseline.

Measures: We assessed the association of weight change within each 4-year interval, with changes in beverage intakes and other lifestyle behaviors during the same period. Multivariate linear regression with robust variance and accounting for within-person repeated measures were used to evaluate the association. Results across the three cohorts were pooled by an inverse-variance-weighted meta-analysis.

Results: Participants gained an average of 1.45 kg (5th to 95th percentile: -1.87 to 5.46) within each 4-year period. After controlling for age, baseline body mass index and changes in other lifestyle behaviors (diet, smoking habits, exercise, alcohol, sleep duration, TV watching), each 1 cup per day increment of water intake was inversely associated with weight gain within each 4-year period (-0.13 kg; 95% confidence interval (CI): -0.17 to -0.08). The associations for other beverages were: sugar-sweetened beverages (SSBs) (0.36 kg; 95% CI: 0.24-0.48), fruit juice (0.22 kg; 95% CI: 0.15-0.28), coffee (-0.14 kg; 95% CI: -0.19 to -0.09), tea (-0.03 kg; 95% CI: -0.05 to -0.01), diet beverages (-0.10 kg; 95% CI: -0.14 to -0.06), low-fat milk (0.02 kg; 95% CI: -0.04 to 0.09) and whole milk (0.02 kg; 95% CI: -0.06 to 0.10). We estimated that replacement of 1 serving per day of SSBs by 1 cup per day of water was associated with 0.49 kg (95% CI: 0.32-0.65) less weight gain over each 4-year period, and the replacement estimate of fruit juices by water was 0.35 kg (95% CI: 0.23-0.46). Substitution of SSBs or fruit juices by other beverages (coffee, tea, diet beverages, low-fat and whole milk) were all significantly and inversely associated with weight gain.

Conclusion: Our results suggest that increasing water intake in place of SSBs or fruit juices is associated with lower long-term weight gain.

Figure 1

Changes in absolute body weight associated with serving-to-serving replacements between beverages per 4-year period Data are based on 20 years of follow-up (1986–2006) in the Nurses’ Health Study, 16 years of follow-up (1991–2007) in the Nurses’ Health Study II, and a 20 years of follow-up (1986–2006) in the Health Professionals Follow-up Study. Values were adjusted for age and baseline body mass index at the beginning of each 4-year period, sleep duration, as well as for changes in physical activity, alcohol use, television watching, smoking, dietary variables (fruits, vegetables, whole grain, refined grain, potatoes, potato chips, red meat, other dairy products, sweets and desserts, nuts, fried foods and trans-fat), and all the beverage variables (water, coffee, sugar-sweetened beverages, fruit juices, whole milk, low-fat milk, tea, and diet beverages) simultaneously within each 4-year period. The results were absolute weight changes (kg) associated with serving-to-serving substitution between beverages, and were pooled by an inverse-variance-weighted random-effects meta-analysis across the three cohorts. The error bars indicate 95% confidence intervals.