(Medicalnewstoday) – The effect of added sucrose in the diet on calorie intake and body weight appears to depend on whether it is in liquid or solid form, according to a new study in mice. If the results translate to humans, they suggest that the contribution of added dietary sugar to obesity comes largely from sugar-sweetened drinks.
A team of scientists in the United Kingdom and China made these suggestions after giving mice added sugar in either their drink or their food for 8 weeks and then comparing them.
In both groups of mice, the added sugar represented 73% of the available dietary calories.
A recent Molecular Metabolism paper carries a full report of the study.
“The consumption of sugar-sweetened beverages,” says John R. Speakman, a professor in the school of biological and environmental sciences at the University of Aberdeen in the U.K., “has been widely implicated as a contributing factor in obesity, and we investigated whether the mode of ingestion (solid or liquid) had different impacts on body weight regulation in mice.”
Prof. Speakman, who led the research at both the University of Aberdeen and the Chinese Academy of Sciences in Beijing, China, is the corresponding and senior author of the new study.
Liquid sucrose led to weight gain
The researchers monitored the mice’s body weight, body fat, calorie intake, and energy expenditure.
They also measured glucose and insulin response as a way to assess how close the animals might come to developing diabetes.
The results showed that the mice that had liquid sucrose in their drinking water consumed more calories, put on more weight, and increased their body fat.
In contrast, the mice that had the same level of added sucrose in their food pellets but drank plain water “were leaner and metabolically healthier than their counterparts exposed to liquid sucrose,” write the authors.
The mice that had increased body fat as a result of drinking liquid sucrose also developed lower tolerance to glucose and sensitivity to insulin, both of which are markers of raised diabetes risk.
However, the authors link these adverse metabolic markers to an increase in body fat and not directly to higher sucrose intake.
Liquid, but not solid, sucrose to blame
In their study discussion, the authors suggest that the findings may explain why their own previous investigations on increased dietary sucrose in mice did not show a significant effect on energy intake and body weight. In those studies, they fed the mice a diet containing only 30% sucrose and delivered it only in solid form.
“The current results demonstrate,” they note, “that when exposed to liquid sucrose, mice had greater energy intake than when offered the same macronutrient composition but in solid form.”
The team also suggests that the findings point to liquid, as opposed to solid, sucrose being a factor on its own.