Dietary adherence and satisfaction with a bean-based high-fiber weight loss diet: a pilot study

Objective. Dietary fiber can reduce hunger and enhance satiety, but fiber intake during hypocaloric weight loss diets typically falls short of recommended levels. We examined the nutritional effects and acceptability of two high-fiber hypocaloric diets differing in sources of fiber: (a) beans or (b) fruits, vegetables, and whole grains. Methods. Subjects were 2 men, 18 women, mean age = 46.9, and mean BMI = 30.6. Subjects completed 3-day food diaries in each of the two baseline weeks. Subjects were then randomized to four weeks on one of two 1400-calorie diets including 25-35 g fiber primarily from 1.5 cups beans/day or from fruits, vegetables, and whole grains. Recommended fiber-rich foods were provided. Subjects kept weekly 3-day food diaries and were assessed weekly. Results. Diet conditions did not differ on outcome measures. Both diets increased fiber intake from 16.6 g/day (SD = 7.1) at baseline to (treatment average) 28.4 g/day (SD = 6.5) (P < 0.001). Fiber intake was consistent over treatment. Caloric intake dropped from 1623.1 kcal/day (SD = 466.9) (baseline) to 1322.2 kcal/day (SD = 275.8) (P = 0.004). Mean weight loss was 1.4 kg (SD = 1.5; P < 0.001). Energy density and self-reported hunger decreased (P's < 0.01) while self-reported fullness increased (P < 0.05). Both diets were rated as potentially acceptable as long as six months. Conclusions. Both diets significantly increased fiber intake by 75%, increased satiation, and reduced hunger. Results support increasing fiber in weight loss diets with a variety of fiber sources.