To better understand the relation between whole-grain consumption and weight gain related to nutrients found in whole grains, we adjusted for potential mediating nutrients, including food sources of fiber, magnesium, folate, and vitamins E and B-6. The association between changes in whole-grain intake and weight gain (0.75 and 1.24 kg weight gain for the highest and the lowest quintile category, respectively; P for trend < 0.0001) was mildly attenuated after adjustment for these nutrients (0.93 and 1.33 kg weight gain, respectively; P for trend < 0.01).
Using the results of our validation study, we further corrected for covariate measurement error in the average changes in body weight associated with quintile changes in grain intakes. After correction for measurement error, the 8-y weight gain associated with a 40-g/d difference in whole-grain intake was 1.1 kg (compared with 0.49 kg, uncorrected).
Dietary fiber was inversely related to weight gain independent of whole grains (P for trend < 0.0001). The men in the lowest quintile of change gained 1.40 kg, whereas the men in the highest quintile of change gained 0.39 kg (Table 4⇓). For every 20-g/d increase in dietary fiber, weight gain was reduced by 1.18 kg. After correction for measurement error, long-term weight gain was reduced by 5.5 kg for each 20-g/d increment in dietary fiber.