Limiting variety in non-nutrient-dense, energy-dense foods during a lifestyle intervention: a randomized controlled trial

Abstract

Background: Dietary variety is a factor that influences consumption but has received little attention in obesity treatment.

Objective: This study examined the effect of limiting the variety of different non-nutrient-dense, energy-dense foods (NND-EDFs) (i.e., chips, ice cream, cookies) on dietary intake and weight loss during an 18-mo lifestyle intervention.

Design: Two hundred two adults aged 51.3 ± 9.5 y with a BMI (in kg/m2) of 34.9 ± 4.3 (57.8% women, 92.2% white) were randomly assigned to 1 of 2 interventions: Lifestyle (1200-1500 kcal/d, ≤30% of energy as fat; n = 101) or Lifestyle + limited variety (LV) (limit variety of NND-EDFs, i.e., 2 choices; n = 101). Both interventions involved 48 group sessions. Dietary intake, NND-EDF hedonics, NND-EDF variety in the home, and weight were assessed at 0, 6, 12, and 18 mo.

Results: Intent-to-treat analyses showed that the Lifestyle+LV group consumed less variety (P < 0.01) and energy daily (P < 0.05) from NND-EDFs than did the Lifestyle group at 6, 12, and 18 mo. The Lifestyle+LV group consumed less total energy daily (P < 0.05) at 6 mo than did the Lifestyle group. The Lifestyle+LV group reported less (P < 0.05) NND-EDF variety in the home at 6 and 18 mo than did the Lifestyle group. The hedonics of one chosen NND-EDF decreased more (P < 0.05) in the Lifestyle+LV group. Despite these effects, no difference in percentage weight loss occurred at 18 mo (Lifestyle+LV: -9.9 ± 7.6%; Lifestyle: -9.6 ± 9.2%).

Conclusions: Limitations in dietary variety decreased intakes in the targeted area but did not affect weight loss. Limiting variety in more areas may be needed to improve weight loss and weight-loss maintenance. This trial was registered at clinicaltrials.gov as NCT01096719.

Figures

FIGURE 1.

Participant flow.

FIGURE 2.

Mean (±SD) number of different non-nutrient-dense, energy-dense foods consumed, assessed by 24-h dietary recall (A) and during the previous 28 d (B) at 0, 6, 12, and 18 mo by intervention. In a mixed-factor ANOVA, significant (P < 0.01) interactions occurred with both methods of assessment; the Lifestyle+LV group (n = 101) consumed significantly fewer different foods than did the Lifestyle group (n = 101) at each time point (***P < 0.001 and **P < 0.01). LV, limited variety.

FIGURE 3.

Mean (±SD) daily energy consumption from non-nutrient-dense, energy-dense foods at 0, 6, 12, and 18 mo by intervention. In a mixed-factor ANOVA, a significant (P < 0.05) interaction occurred; the Lifestyle+LV group (n = 101) consumed significantly less energy than did the Lifestyle group (n = 101) at each time point (**P < 0.01 and *P < 0.05). LV, limited variety.

FIGURE 4.

Mean (±SD) percentage weight loss at 6, 12, and 18 mo by intervention. In a mixed-factor ANOVA, a significant main effect of time occurred; percentage weight loss was significantly (**P < 0.01) greater at 6 and 12 mo than at 18 mo (Lifestyle+LV: n = 101; Lifestyle: n = 101). LV, limited variety.