Dietary sugars and body weight: systematic review and meta-analyses of randomised controlled trials and cohort studies

Abstract

Objective To summarise evidence on the association between intake of dietary sugars and body weight in adults and children.Design Systematic review and meta-analysis of randomised controlled trials and prospective cohort studies.Data sources OVID Medline, Embase, PubMed, Cumulative Index to Nursing and Allied Health Literature, Scopus, and Web of Science (up to December 2011).Review methods Eligible studies reported the intake of total sugars, intake of a component of total sugars, or intake of sugar containing foods or beverages; and at least one measure of body fatness. Minimum duration was two weeks for trials and one year for cohort studies. Trials of weight loss or confounded by additional medical or lifestyle interventions were excluded. Study selection, assessment, validity, data extraction, and analysis were undertaken as specified by the Cochrane Collaboration and the GRADE working group. For trials, we pooled data for weight change using inverse variance models with random effects. We pooled cohort study data where possible to estimate effect sizes, expressed as odds ratios for risk of obesity or β coefficients for change in adiposity per unit of intake.Results 30 of 7895 trials and 38 of 9445 cohort studies were eligible. In trials of adults with ad libitum diets (that is, with no strict control of food intake), reduced intake of dietary sugars was associated with a decrease in body weight (0.80 kg, 95% confidence interval 0.39 to 1.21; P<0.001); increased sugars intake was associated with a comparable weight increase (0.75 kg, 0.30 to 1.19; P=0.001). Isoenergetic exchange of dietary sugars with other carbohydrates showed no change in body weight (0.04 kg, −0.04 to 0.13). Trials in children, which involved recommendations to reduce intake of sugar sweetened foods and beverages, had low participant compliance to dietary advice; these trials showed no overall change in body weight. However, in relation to intakes of sugar sweetened beverages after one year follow-up in prospective studies, the odds ratio for being overweight or obese increased was 1.55 (1.32 to 1.82) among groups with the highest intake compared with those with the lowest intake. Despite significant heterogeneity in one meta-analysis and potential bias in some trials, sensitivity analyses showed that the trends were consistent and associations remained after these studies were excluded.Conclusions Among free living people involving ad libitum diets, intake of free sugars or sugar sweetened beverages is a determinant of body weight. The change in body fatness that occurs with modifying intakes seems to be mediated via changes in energy intakes, since isoenergetic exchange of sugars with other carbohydrates was not associated with weight change.

The role of low-calorie sweeteners in the prevention and management of overweight and obesity: evidence v. conjecture

“…Additionally, the finding that iso-energetic exchange of sugars with other carbohydrates does not change body weight indicates that this effect is not specific to sugar (22) . In other words, it is the difference in energy density of the diet that affects body weight (fatness).…”

“…The studies included in this review (19) are the same as some of the studies that have been cited as demonstrating that consumption of free sugars increases body weight (22) . Additionally, the finding that iso-energetic exchange of sugars with other carbohydrates does not change body weight indicates that this effect is not specific to sugar (22) .…”

Combating the dual burden: therapeutic targeting of common pathways in obesity and type 2 diabetes

“…Weight loss seems to be mediated via changes in energy intakes rather than diet composition 41 . Similarly, diet composition has little effect on glycaemic control independent of total calories 40 .…”

Sickeningly Sweet: Does Sugar Cause Type 2 Diabetes? Yes

“…Sievenpiper, my opponent in this debate, proffers numerous systematic reviews and meta-analyses, hierarchically considered to be the highest quality evidence. They state that fructose does not contribute to obesity (29,30). But this debate is not about obesity; it is about chronic metabolic disease.…”