Obesity in children is a massive issue in both the UK and the US with up to a third of youngsters in each country considered overweight. Canadian researchers found pregnant rats fed two of the most common sweeteners, stevia or aspartame, had pups that were fatter. Experts believe the findings may also apply to expectant mothers, given an array of other studies have found similar in humans, which means mothers-to-be who consume lots of artificial sweeteners may be more likely to have children who end up obese.
Artificial sweeteners, that can be added to drinks or sprinkled over food, are used by millions to cut their calorie intake and lower sugar consumption. The thinking is that these sweeteners, which have few or no calories, are better for the waistline and don’t increase blood sugar levels.
Professor Reimer and colleagues split the pregnant rats into three groups. Some were given aspartame, which is used in Diet Coke, others were given stevia which is used in 7UP Free. A third group of pregnant rats were given water, allowing the researchers to detect any differences between the groups. Their pups were weighed as soon as they gave birth with tests carried out to see how their mother's diet affected their gut bacteria.
Barely any effects were visible on the rats which had given birth, but they found pups born to sweetener-fed mothers were heavier with a higher percentage of body fat. They also showed higher levels of some microbes and fewer of others. Researchers believe these changes in their microbiome may explain why they gained more weight.
A number of other studies have also explored the negative impacts of sweeteners used in diet soft drinks on obesity. Last year researchers at the University of Southern California tested the impact of sucralose on 74 volunteers and found it actually increased food cravings. But official NHS advice says research into sweeteners and appetite stimulation is inconsistent and that diet soft drinks can provide a healthier alternative to people with diabetes who need to keep an eye on their blood sugar levels.
