Changes in diet and lifestyle and long-term weight gain in women and men

Abstract

Background: Specific dietary and other lifestyle behaviors may affect the success of the straightforward-sounding strategy "eat less and exercise more" for preventing long-term weight gain.

Methods: We performed prospective investigations involving three separate cohorts that included 120,877 U.S. women and men who were free of chronic diseases and not obese at baseline, with follow-up periods from 1986 to 2006, 1991 to 2003, and 1986 to 2006. The relationships between changes in lifestyle factors and weight change were evaluated at 4-year intervals, with multivariable adjustments made for age, baseline body-mass index for each period, and all lifestyle factors simultaneously. Cohort-specific and sex-specific results were similar and were pooled with the use of an inverse-variance-weighted meta-analysis.

Results: Within each 4-year period, participants gained an average of 3.35 lb (5th to 95th percentile, -4.1 to 12.4). On the basis of increased daily servings of individual dietary components, 4-year weight change was most strongly associated with the intake of potato chips (1.69 lb), potatoes (1.28 lb), sugar-sweetened beverages (1.00 lb), unprocessed red meats (0.95 lb), and processed meats (0.93 lb) and was inversely associated with the intake of vegetables (-0.22 lb), whole grains (-0.37 lb), fruits (-0.49 lb), nuts (-0.57 lb), and yogurt (-0.82 lb) (P≤0.005 for each comparison). Aggregate dietary changes were associated with substantial differences in weight change (3.93 lb across quintiles of dietary change). Other lifestyle factors were also independently associated with weight change (P<0.001), including physical activity (-1.76 lb across quintiles); alcohol use (0.41 lb per drink per day), smoking (new quitters, 5.17 lb; former smokers, 0.14 lb), sleep (more weight gain with <6 or >8 hours of sleep), and television watching (0.31 lb per hour per day).

Conclusions: Specific dietary and lifestyle factors are independently associated with long-term weight gain, with a substantial aggregate effect and implications for strategies to prevent obesity. (Funded by the National Institutes of Health and others.).

Figure 1. Relationships between Changes in Food and Beverage Consumption and Weight Changes Every 4 Years, According to Study Cohort

Study participants included 50,422 women in the Nurses’ Health Study (NHS), followed for 20 years (1986 to 2006); 47,898 women in the Nurses’ Health Study II (NHS II), followed for 12 years (1991 to 2003); and 22,557 men in the Health Professionals Follow-up Study (HPFS), followed for 20 years (1986 to 2006). Weight changes are reported for each increase in the daily serving of the food or beverage; decreased intake would be associated with the inverse weight changes. There was little evidence of a significant interaction between diet and physical activity (P>0.10 for the interaction in each cohort). All weight changes were adjusted simultaneously for age, baseline body-mass index, sleep duration, and changes in smoking status, physical activity, television watching, alcohol use, and all of the dietary factors shown. The P value is less than 0.001 for all dietary factors with the exception of butter in the NHS II, cheese in the NHS and NHS II, low-fat or skim milk in the NHS and HPFS, diet soda in the NHS, and whole-fat milk in all three cohorts.

Figure 2. Relationships between Changes in Diet and Physical Activity and Weight Changes within Each 4-Year Period in the Three Cohorts

In a multivariable-adjusted analysis, overall dietary changes among the 120,877 men and women in the three cohorts were based on the sum of changes in the intake of fruits, vegetables, whole grains, nuts, refined grains, potatoes or french fries, potato chips, butter, yogurt, sugar-sweetened beverages, 100%-fruit juice, sweets and desserts, processed meats, unprocessed red meats, trans fat, fried foods consumed at home, and fried foods consumed away from home. Panel A shows the relationship between deciles of dietary change and weight change per 4-year period in the three cohorts separately and combined. As compared with persons in the top decile, persons in the bottom decile had a 5.48-lb greater weight gain (95% confidence interval [CI], 4.02 to 6.94). Panel B shows the relationship between the cross-stratified quintiles of changes in both dietary habits and physical activity with weight changes per 4-year period for the combined cohorts. As compared with persons in the top quintiles of both dietary change and physical-activity change, persons in the lowest quintiles had a 5.93-lb greater weight gain (95% CI, 4.35 to 7.52). There was little evidence of a significant interaction between diet and physical activity (P>0.10 for the interaction in each cohort). All weight changes were adjusted for age, baseline body-mass index, sleep duration, and changes in smoking status, physical activity, television watching, and alcohol use. P<0.001 for all comparisons.