Consumption of Whole-Grain Cereals during Weight Loss: Effects on Dietary Quality, Dietary Fiber, Magnesium, Vitamin B-6, and Obesity

Abstract

Objective While various weight-management approaches produce weight loss, they may differ in dietary quality. We monitored changes in nutrient intakes in overweight and obese subjects on three different weight-management programs. Design Randomized clinical trial (pilot study) with two 12-week phases: phase 1, weekly counseling; phase 2, monitoring only. Subjects/setting One hundred eighty nonsmoking, sedentary overweight and obese adults began this outpatient study; 134 (body mass index [calculated as kg/m 2]=30.9±2.4; age=42.3±1.2 years) were used in analyses. Intervention Twenty-four weeks of exercise only (control group), hypocaloric diet plus exercise, or hypocaloric diet with fiber-rich whole-grain cereals plus exercise. Main Outcome Measures At weeks 0, 12, and 24, diet quality was assessed by 3-day food records and body weight was measured. Statistical Analyses Performed Three-way analysis of variance with repeated measures. Results The hypocaloric diet with fiber-rich whole-grain cereals plus exercise decreased energy intake more than exercise only ( P=0.032). By week 12, the hypocaloric diet with fiber-rich whole-grain cereals plus exercise and the hypocaloric diet plus exercise decreased total fat more than exercise only, which was sustained in the hypocaloric diet with fiber-rich whole-grain cereals plus exercise at 24 weeks ( P<0.001). At weeks 12 and 24, the hypocaloric diet with fiber-rich whole-grain cereals plus exercise reduced saturated fat intake more than exercise only. The hypocaloric diet with fiber-rich whole-grain cereals plus exercise increased total fiber, insoluble fiber (both P<0.001), magnesium ( P=0.004), and vitamin B-6 ( P=0.002) intakes more than the hypocaloric diet plus exercise and exercise only. Calcium and vitamin E intakes were inadequate in all groups. Weight loss was similar in the hypocaloric diet with fiber-rich whole-grain cereals plus exercise and the hypocaloric diet plus exercise. Conclusions Weight-reduction strategies may be associated with reduced intake of micronutrients, such as calcium and vitamin E. However, a hypocaloric diet with fiber-rich whole-grain cereal is effective for improving or maintaining other aspects of dietary quality during weight loss.