Walking attenuates the relationships of high-meat, low-fruit dietary intake to total and regional adiposity in men and women.

Vigorous physical activity (running) has been shown to attenuate the association between diet and body weight. Walking is the most popular physical activity, but is a moderate-intensity physical activity because it requires less than sixfold the energy expenditure of sitting at rest. We therefore examined whether reported distance walked per week affected the relationship of diet to BMI and circumferences of the waist, hip, and chest in 30,014 female and 7,133 male participants of the National Walkers' Health Study. Reported meat and fruit intakes served as indicators of high-risk diets for weight gain. The analyses showed that higher meat and lower fruit intake were significantly and consistently associated with greater BMI and waist circumference at all activity levels. Longer usual walking distance significantly attenuated the concordant relationships of diet with women's BMIs (P < 10(-8)), men's BMIs (P = 0.04), and women's waist (P < 10(-6)), hip (P = 0.0001), and chest circumferences (P < 10(-5)). Compared to walkers who averaged <1.5 km/day, the association of diet with adiposity in subjects who walked ≥1.5 km/day was reduced 21% in women and 31% in men for BMI; 20% in women and 27% in men for waist circumference; 19% for women's hip circumference; and 26% for women's chest circumference. Thus we conclude that diets characterized by high-meat/low-fruit intake were significantly associated with greater BMI, and this association was attenuated by moderate physical activity. The weaker results in men than women probably related to the smaller sample size, and reduced statistical power of the men.