Date of Award

8-2011

Degree Type

Dissertation

Degree Name

Doctor of Philosophy

Major

Nutritional Sciences

Major Professor

Hollie A. Raynor

Committee Members

Betsy Haughton, Marsha L. Spence, Eugene C. Fitzhugh

Abstract

Improved weight loss interventions are needed to help reduce obesity. One dietary factor that has been effective in increasing weight loss is increased dietary structure. One method for increasing dietary structure is prescribing the frequency in which eating bouts (meals and snacks) occur. Eating frequency (EF) has been inversely related to body mass index (BMI) but the impact of EF on weight loss is unclear. This randomized controlled trial examined the effect of EF on hunger, the relative-reinforcing value of food, energy intake (EI), and weight loss during a 6 month behavioral weight loss intervention. Participants (age: 51.0 ± 9.9 yrs, BMI: 35.5 ± 4.8 kg/m2, 57.8% female, 94.1% white) were randomized to one of two EF prescriptions: 1) Three Meal (n=25): three eating bouts/day; or 2) Grazing (n=26): eat at least 100 kcals every 2-3 hrs. Both groups attended 20 sessions and had identical dietary (1200–1500 kcals/day, < 30% kcals from fat) and physical activity (200 minutes/wk) goals. Hunger, relative-reinforcing value of food, diet, and anthropometric data were collected at 0 and 6 months. Using intent-to-treat analyses, Grazing reported a greater EF (eating bouts in which > 25 kcals were eaten/day) than Three Meal at 6 months (5.8 ± 1.1 eating bouts vs. 3.2 ± 0.6 eating bouts, p<0.001). On a 100-mm visual analogue scale Grazing reported significantly less hunger at 6 months as compared to 0 months (47.9 ± 18.5 mm vs. 56.3 ± 15.7 mm, p<0.05), while Three Meal did not report any changes. There were no significant differences in the relative-reinforcing value of food between groups or over time. EI and BMI were significantly (p<0.001) reduced from 0 to 6 months (EI: 0 months = 2198 ± 692 kcals/day vs. 6 months = 1266 ± 353 kcals/day; BMI: 0 months = 35.5 ± 4.8 kg/m2 vs. 6 months = 30.6 ± 4.9 kg/m2). There were no significant differences in EI or BMI between the groups. An EF of approximately six eating bouts/day may decrease hunger more so than an EF of three meals/day while consuming a low-kcal diet during a behavioral weight loss intervention.

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