Low glycaemic index or low glycaemic load diets for overweight and obesity

Abstract

Background: Obesity is increasingly prevalent, yet the nutritional management remains contentious. It has been suggested that low glycaemic index or load diets may stimulate greater weight loss than higher glycaemic index or load diets or other weight reduction diets.

Objectives: To assess the effects of low glycaemic index or load diets for weight loss in overweight or obese people.

Search strategy: Trials were identified through The Cochrane Library, MEDLINE, EMBASE, CINAHL and manual searches of bibliographies.

Selection criteria: Randomised controlled trials comparing a low glycaemic index or load diet (LGI) with a higher glycaemic index or load diet or other diet (Cdiet) in overweight or obese people.

Data collection and analysis: Two authors independently selected trials, assessed quality and extracted data, including any information provided on adverse effects.

Main results: We identified six eligible randomised controlled trials (total of 202 participants). Interventions ranged from five weeks to six months duration with up to six months follow-up after the intervention ceased. The decrease in body mass (WMD -1.1 kg, 95% confidence interval (CI) -2.0 to -0.2, P < 0.05) (n = 163), total fat mass (WMD -1.1 kg, 95% CI -1.9 to -0.4, P < 0.05) (n =147) and body mass index (WMD -1.3, 95% CI -2.0 to -0.5, P < 0.05) (n = 48) was significantly greater in participants receiving LGI compared to Cdiets. The decrease in total cholesterol was significantly greater with LGI compared to Cdiets (WMD -0.22 mmol/L, 95% CI -0.43 to -0.02, P < 0.05), as was the change in LDL-cholesterol (WMD -0.24 mmol/L, 95% CI -0.44 to -0.05, P < 0.05). No study reported adverse effects, mortality or quality of life data.

Authors' conclusions: Overweight or obese people on LGI lost more weight and had more improvement in lipid profiles than those receiving Cdiets. Body mass, total fat mass, body mass index, total cholesterol and LDL-cholesterol all decreased significantly more in the LGI group. In studies comparing ad libitum LGI diets to conventional restricted energy low-fat diets, participants fared as well or better on th LGI diet, even though they could eat as much as desired. Lowering the glycaemic load of the diet appears to be an effective method of promoting weight loss and improving lipid profiles and can be simply incorporated into a person's lifestyle. Further research with longer term follow-up will determine whether improvement continues long-term and improves quality of life.

Conflict of interest statement

None known.

Figures

1

Adapted QUOROM (quality of reporting of meta‐analyses) flow‐chart of study selection

1.1. Analysis

Comparison 1 Low glycaemic diet versus high glycaemic or other diet, Outcome 1 change in body mass (kg).

1.2. Analysis

Comparison 1 Low glycaemic diet versus high glycaemic or other diet, Outcome 2 change in total fat mass (DXA kg).

1.3. Analysis

Comparison 1 Low glycaemic diet versus high glycaemic or other diet, Outcome 3 change in body mass index (BMI units).

1.4. Analysis

Comparison 1 Low glycaemic diet versus high glycaemic or other diet, Outcome 4 change in total cholesterol concentration (mmol/L).

1.5. Analysis

Comparison 1 Low glycaemic diet versus high glycaemic or other diet, Outcome 5 change in LDL cholesterol concentration (mmol/L).

1.6. Analysis

Comparison 1 Low glycaemic diet versus high glycaemic or other diet, Outcome 6 change in HDL cholesterol concentration (mmol/L).

1.7. Analysis

Comparison 1 Low glycaemic diet versus high glycaemic or other diet, Outcome 7 change in triglycerides concentration (mmol/L) and % change (%).

1.8. Analysis

Comparison 1 Low glycaemic diet versus high glycaemic or other diet, Outcome 8 change in fat free mass (kg).

1.9. Analysis

Comparison 1 Low glycaemic diet versus high glycaemic or other diet, Outcome 9 fasting plasma glucose concentration: final concentrations (mmol/L) and change in concentration (mmol/L).

1.10. Analysis

Comparison 1 Low glycaemic diet versus high glycaemic or other diet, Outcome 10 fasting plasma insulin concentration: final concentrations (pmol/L) and change in concentration (pmol/L).

1.11. Analysis

Comparison 1 Low glycaemic diet versus high glycaemic or other diet, Outcome 11 free fatty acids: final concentrations (umol/L) and change in concentration (umol/L).

1.12. Analysis

Comparison 1 Low glycaemic diet versus high glycaemic or other diet, Outcome 12 systolic blood pressure: change (mmHg) and % change (%).

1.13. Analysis

Comparison 1 Low glycaemic diet versus high glycaemic or other diet, Outcome 13 diastolic blood pressure: change (mmHg) and % change (%).