Higher Carbohydrate Amount and Lower Glycemic Index Increase Hunger, Diet Satisfaction, and Heartburn in Overweight and Obese Adults in the OmniCarb Randomized Clinical Trial

Abstract

Background: The Dietary Approaches to Stop Hypertension (DASH) diet, a high-carbohydrate diet, is highly recommended based on its cardiovascular risk benefits, yet adherence remains persistently low. How subjective impressions of this diet contribute to adherence has not been thoroughly explored. The OmniCarb trial, which compared DASH-style diets varying in glycemic index (GI) and carbohydrate amount, surveyed subjective impressions of such diets.

Objectives: We examined the effects of GI and carbohydrate amount on qualitative aspects of diet acceptability through secondary outcomes in the OmniCarb trial.

Methods: OmniCarb was a randomized, crossover trial of 4 DASH-style diets varying by GI (≥65 compared with ≤45) and carbohydrate amount (40% compared with 58% kcal) in overweight or obese (BMI ≥25 kg/m2) adults (n = 163). Participants consumed each diet in random order over 5-wk periods, separated by 2-wk washouts. At baseline and the end of each feeding period, participants rated hunger, diet satisfaction, and gastrointestinal symptoms (diarrhea/loose stools, constipation, bloating, nausea, and heartburn).

Results: Participant mean age was 52 y, with 52% women, 51% non-Hispanic black, and 56% obese (BMI ≥30). Compared with baseline, all intervention diets decreased heartburn, increased diarrhea/loose stools, and increased bloating, but did not significantly affect constipation or nausea. Compared with lower carbohydrate diets, higher carbohydrate diets increased hunger (RR: 1.16; 95% CI: 1.04, 1.30), increased diet satisfaction (RR: 1.10; 95% CI: 1.01, 1.20), and increased heartburn (RR: 1.49; 95% CI: 1.09, 2.04). Compared with lower GI diets, higher GI diets did not affect hunger (RR: 0.92; 95% CI: 0.83, 1.02), decreased diet satisfaction (RR: 0.83; 95% CI: 0.75, 0.92), and did not affect heartburn (RR: 0.89; 95% CI: 0.70, 1.13). There were no between-diet differences for diarrhea/loose stools, constipation, bloating, and nausea.

Conclusions: Although a higher carbohydrate amount in DASH-style diets can increase diet satisfaction, it can also decrease satiety and increase heartburn in adults with overweight or obesity.This trial is registered at clinicaltrials.gov as NCT00608049.

Keywords: OmniCarb; carbohydrates; diet satisfaction; gastrointestinal symptoms; glycemic index; hunger.

Published by Oxford University Press on behalf of the American Society for Nutrition 2021.

Figures

FIGURE 1

Gastrointestinal symptoms of diarrhea/loose stools (A), constipation (B), bloating (C), nausea/upset stomach (D), and heartburn (E) at the end of baseline diet and intervention diets varying in carbohydrate content and glycemic index in adults with overweight or obesity. Baseline diet n = 163; CG diet n = 150; Cg diet n = 153; cG diet n = 152; cg diet n = 153. CG, higher carbohydrate, higher glycemic index diet; Cg, higher carbohydrate, lower glycemic index diet; cG, lower carbohydrate, higher glycemic index diet; cg, lower carbohydrate, lower glycemic index diet.

FIGURE 2

Comparisons of hunger (A), diet satisfaction (B), and heartburn (C) symptoms between intervention diets varying in carbohydrate content and glycemic index in adults with overweight or obesity. Values are RR and 95% CI. Number of measurements for hunger and diet satisfaction symptoms: C diet n = 302; c diet n = 305; Cg diet n = 153; cG diet n = 152; CG diet n = 149; cg diet n = 153; G diet n = 301; g diet n = 306. Number of measurements for heartburn symptoms: C diet n = 303; c diet n = 305; Cg diet n = 153; cG diet n = 152; CG diet n = 150; cg diet n = 153; G diet n = 302; g diet n = 306. C, higher carbohydrate diets combined (CG and Cg); c, lower carbohydrate diets combined (cG and cg); Carb, carbohydrate amount; CG, higher carbohydrate, higher glycemic index diet; Cg, higher carbohydrate, lower glycemic index diet; cG, lower carbohydrate, higher glycemic index diet; cg, lower carbohydrate, lower glycemic index diet; G, higher glycemic index diets combined (CG and cG); g, lower glycemic index diets combined (Cg and cg); GI, glycemic index.