Cutting sugar has a small but important effect on body weight, says BMJ meta-analysis

Sugar reduction in foods should form part of strategies to reduce overweight and obesity, according to researchers who argue that cutting sugar intake has a ‘small but significant’ effect on weight.

The paper, published in the British Medical Journal (BMJ), reviews the evidence for a potential association between intake of dietary sugars and body weight in adults and children – finding that although the effect of cutting sugar is relatively small, it may have significant benefits in terms of the global health costs.

Led by Professor Jim Mann from the University of Otago, New Zealand, the research team performed a systematic review and further meta-analysis of randomised controlled trials and prospective cohort studies, finding that reduced intake of dietary sugars is associated with a decrease in body weight by an average of 0.8 kilograms (kg), while advice to increase intake was associated with a corresponding 0.75 kg increase.

Mann and his colleagues suggest that this finding provides support for international guidelines to cut sugar intake to less than 10% of total energy to help reduce the global obesity epidemic.

“The meta-analyses based on controlled trials provide consistent evidence that increasing or decreasing intake of dietary sugars from current levels of intake is associated with corresponding changes in body weight in adults,” said the researchers.

“The data suggest that the change in body fatness that occurs with modifying intake of sugars results from an alteration in energy balance rather than a physiological or metabolic consequence of monosaccharides or disaccharides,” they said, adding that the extent to which population based advice to reduce sugars might reduce risk of obesity cannot be extrapolated from the present findings, because few data from the studies lasted longer than ten weeks.

“However, when considering the rapid weight gain that occurs after an increased intake of sugars, it seems reasonable to conclude that advice relating to sugars intake is a relevant component of a strategy to reduce the high risk of overweight and obesity in most countries,” suggested Mann and his team.