Objectives: This study examined cross-sectional and prospective relationships between macronutrient intake, behaviors intended to limit fat intake, physical activity and body weight.
Design: The overall goal was to identify diet and exercise behaviors that predict and/or accompany weight gain or loss over time. Specific questions addressed included: (a) are habitual levels of diet or exercise predictive of weight change; (b) are habitual diet and exercise levels associated cross-sectionally with body weight; and (c) are changes in diet and exercise associated with changes in body weight over time?
Participants: Subjects were a sample of community volunteers (n=826 women, n=218 men) taking part in a weight gain prevention project over a 3-year period.
Measures: Body weight was measured at baseline and annually over the study period. Self-report measures of diet and exercise behavior were also measured annually.
Results: Among both men and women, the most consistent results were the positive association between dietary fat intake and weight gain and an inverse association between frequency of physical activity and weight gain. Individuals who weighed more both ate more and exercised less than those who weighed less. Individuals who increased their physical activity level and decreased their food intake over time were protected from weight gain compared to those who did not. Frequency of high-intensity physical activity was particularly important for both men and women. Additionally, women who consistently engaged in higher levels of moderate physical activity gained weight at a slower rate compared to women who were less active.
Conclusions: Overall results indicated that both cross-sectionally and prospectively, the determinants of weight and weight change are multifactorial. Attention to exercise, fat intake and total energy intake all appear important for successful long term control of body weight.