The Link With Weight Is Not Clear-cut

Whether or not artificial sweeteners can help you lose weight is more contentious. On one hand, since they are calorie free, they can be useful in reducing overall energy consumption. On the other hand, a number of studies have actually associated them with weight gain.

Clare says:"Weight gain has been suggested as a side effect of consumption of artificial sweeteners, diet drinks in particular. A number of hypotheses have been put forward for this, including artificial sweeteners failing to activate the 'food reward pathway'. This would mean the craving for sweet foods continues, and more food and larger portions are consumed."

She points out, however, that the link is mainly based on observational studies, and does not take account of other factors such as overall calorie consumption. After all, swapping sugary drinks for diet ones won't help you lose weight if you offset the difference with a doughnut.

While a small number of studies have linked sucralose and saccharin with increased levels of insulin production – possibly due to changes in gut bacteria – the jury's out on how artificial sweeteners affect your blood sugar. So far, the evidence is not sufficiently robust to say.

If you've been trying to avoid artificial sweeteners, you may be familiar with a natural alternative, namely stevia. Derived from the stevia plant, this sweetener is around 200 times sweeter than sugar, while remaining calorie-free. It was approved in the US in 2008, and in Europe in 2011, and has become steadily more popular ever since. Some studies have suggested that stevia might have health benefits. 

However, some consumers have complained of a bitter or licorice-like aftertaste, meaning it may not be a true substitute for sugar. A number of products containing stevia are sweetened with sugar too.