ody weight in children. However, this was attributed to poor compliance: the children did not always adhere to their assigned levels of sugar intake.
A key conclusion was that consumption of sugar-sweetened beverages was particularly likely to lead to increased body weight in both adults and children. This confirmsÂ previous findingsÂ that sugar in liquid form is closely associated with weight increase.
In anÂ editorial accompanying the BMJ paper, two experts comment that,
“Sugar in this form does not induce satiety to the same degree as it does in solid form, which makes overconsumption easier. Because of this, and the large amounts of sugar consumed in drinks, reducing the intake of sugar sweetened drinks is a high priority.”
The BMJ paper also reported that when energy intake is kept constant, replacing sugars with other carbohydrates, protein or fat does not lead to significant weight reduction. So it appears that itâ€™s the over-consumption of total kilojoules that leads to weight increase when sugar intake is high, possibly because sugars consumed in liquid form are less likely to leave you feeling full.
The authors do not discount the possibility that the increase in weight may be due to particular metabolic effects uniquely attributable to fructose, asÂ hypothesised by Robert Lustig, a US professor of paediatrics. But theÂ editorial accompanying the BMJ paperÂ argues against this â€śfructose hypothesisâ€ť, stating that â€śthere is no good evidence that replacement of fructose with glucose would be beneficial.â€ť
The editorial also points out that â€śâ€¦ many starchy foods, particularly highly processed grains and potato products, have a high glycemic index, raising blood glucose and insulin more rapidly than an equivalent amount of sucrose.â€ť
So does the BMJ paper change our understanding of what is driving the obesity epidemic?
The short answer is no. Rather, the paper provides additional evidence that high intakes of sugar are almost certainly harmful to health, not least through their tendency to promote weight gain.
The authors also make it clear that, contrary to the belief of many members of the public, sugar intake is almost certainly not the only driver of the obesity epidemic. They point out, for example, that the effect of varying sugar consumption on body weight is relatively small, and that this is unsurprising, â€śowing to the multifactorial causes of obesityâ€ť.
So what should we do with this knowledge?
Clearly, avoiding excessive sugar intake would be prudent, but this has been recommended for as long as dietary guidelines have been in existence in Australia (and in most other nations). The current wording of theÂ relevant Australian guidelineÂ is, â€śConsume only moderate amounts of sugars and foods containing added sugarsâ€ť.
This wording is likely to be altered when theÂ revised guidelines are publishedÂ next month. At present, the draft revised guideline reads: â€śLimit intake of foods and drinks containing added sugars. In particular, limit sugar-sweetened drinks.â€ť
That sounds like good advice to me!
** Chris Forbes-Ewan is Senior Nutritionist at the Defence Science and Technology Organisation.Â Chris Forbes-Ewan received funding from the National Health and Medical Research Council in 2006 for his contribution to the development of Nutrient Reference Values for Australia and New Zealand. His contribution was in the area of estimated energy requirements.
Some thoughts on how the public health sector can learn from @IndigenousX and its pitch to the #ShortyAwards