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With our appetite for low or zero sugar products increasing, artificial sweeteners are big business.

Food or drinks containing artificial sweeteners are often marketed as a healthier option, and it’s understandable why. Because artificial sweeteners are significantly sweeter than sugar, they can be used in very small amounts and contribute little to no calories. There are lots of types, but the most well researched are aspartame and saccharin.

A possible link between artificial sweeteners and cancer has been reported in the media. But despite lots of research in this area, there’s no convincing evidence that sweeteners in our food and drink increase the risk of cancer.

While there’s nothing to worry about from a cancer perspective, questions still remain about whether or not artificial sweeteners can help us lose weight. And as being overweight or obese increases the risk of 13 types of cancer, knowing whether they help is important.

But getting a solid answer to this question is tricky. Diet is notoriously difficult to study and so far, researchers have reached different conclusions. Overall, it looks like artificial sweeteners like aspartame aren’t causing harm, but they’re not having the big weight loss benefits that some people expected either.

Can we have our cake and eat it too?

If sweeteners are replacing a high calorie alternative, it seems logical that by reducing calories they should help with weight loss.

But whether this is the case is tricky to prove. It’s difficult to study the long-term impact of a specific part of our diet for lots of reasons. For one, measuring exactly how much people consume is hard. And there are lots of other things that could explain any differences – like other elements of a person’s diet or how much they exercise – so we need large studies that take these things in to account.

Most studies have looked at artificially sweetened drinks rather than sweeteners in foods, and the results are mixed. For this reason, the European Food Safety Authority won’t allow products containing artificial sweeteners to carry a weight loss health claim.

A 2016 review found that people using artificial sweeteners had both a lower calorie intake and reduced body weight. But these results should be treated with a healthy dose of scepticism as the study was conducted and funded by the International Life Sciences Institute, whose members include companies such as Coca-Cola, Red Bull and Pepsi. Each of these companies has a vested interested in the artificial sweetener business.

The results also don’t fully tally up with a more recent, independent analysis of 56 studies. This analysis found very little evidence to suggest low energy artificial or natural sweeteners, like stevia, are helping lots of people to lose weight.

But when 3 studies were picked out that only included overweight or obese adults, artificial sweeteners did provide a small benefit to weight loss. While positive for this group of people, the researchers say that larger and longer-term studies are needed to confirm this.

If not weight loss, then what about weight gain?

Surprisingly, some research has found that sweeteners might make us gain weight. But the latest review didn’t agree with this.

This raises an important question: if products containing artificial sweeteners contain less calories, why doesn’t the evidence show they are helping us to lose weight?

One explanation is something called ‘reverse causality’ – whereby people who are already overweight or obese are more likely to be choosing food or drinks with sweeteners to help with weight loss. This makes it difficult to say whether the artificial sweeteners or weight gain came first, or how one may affect the other.

But some researchers think there might be more going on, including effects on our gut health, appetite and desire for sweet foods.

But these are unproven theories.

Are sweeteners actually making us hungrier?

Throughout the day, our gut sends messages to our brain in the form of hormones. These hormones tell our brain when we are hungry or full. There has been some suggestion that sweeteners could interfere with these messages, and therefore make us eat more rather than less.

‘’When we eat food containing sugar, the gut produces more of the hormone that tells our brain we are full, and less of the hormone that tells our brain we are hungry. Currently, the evidence suggests that sweeteners don’t prompt the release of either of these gut hormones in humans,’ says Dr Ana Pinto, a nutrition researcher from King’s College London (KCL).

Does a diet or low-calorie option at lunch equal more at dinner?

If sweeteners aren’t affecting our gut, is there a psychological effect?

Some research has proposed a reward effect, in which we feel we have some ‘calories to spare’ if we have replaced a high calorie product with a diet alternative.

Daphne Katsikioti, who also studies nutrition at KCL, explains: “‘Some researchers have suggested that when we eat or drink products containing artificial sweeteners, we later compensate for the ‘missing’ energy by eating more.”

But she adds that there’s good evidence to suggest that this doesn’t happen and that artificial sweeteners can be helpful to reduce calories.

Finally, some people have suggested that the intense sweetness that comes from sweeteners could lead to a particularly sweet tooth in the long term. The latest review found very little evidence of this, so more research is needed to pin down if this a possible side effect of artificial sweeteners.

To sweeten or not to sweeten?

Despite the theories, the European Food Safety Authority have ruled that artificial sweeteners in food and drink pose no threat to our health if consumed within daily allowances. For aspartame, this is equivalent to 15 cans of diet coke. That’s a stark contrast to what we know about the harms of having too much sugar.

But products containing sweeteners often don’t offer much nutritional benefit. And the lack of convincing evidence that they can help with weight loss shouldn’t be overlooked.

The take-home message is artificially sweetened drinks aren’t a silver bullet for weight loss. But if you drink a lot of sugary drinks and think a diet version might help you cut down on sugar, that’s a good step and is very unlikely to do you any harm.

Katie Patrick is a health information officer at Cancer Research UK 

Comments

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Sherie Sanders, MA July 9, 2019

You are deliberately obscuring the risks of artificial sweeteners and scapegoating obesity. If you were real scientists, instead of representing corporate interests, you would know that obesity is associated with cancer, it has NOT been proven to cause it. It may very well be that all the artificial sweeteners is the true culprit, as fatter people are pressured into dieting more often. But, you care more about spin than science.

James May 21, 2019

An actually well written article about aspartame, very nice.

I agree with everything written. There’s no research to definitively say that aspartame is bad for us in any way, and if anything, it’s helpful when it comes to weight loss.

But as you say, not all research can confirm it because too many obese individuals view low calorie products as silver bullets, when in reality they’re just one option of assisting weight management. So unless the rest of the diet and lifestyle is on point, it won’t do anything to help. Might even make it worse as obese people are likely to eat even more, thinking that by using a low calorie drink, they can allow themselves more of other stuff.

Personally I use artificial sweeteners with tea and coffee, as well as drink diet soda to make sure all liquids I consume are zero calorie, meaning I only need to worry about actual food when it comes to dieting.

Alison May 9, 2019

My greatest concern is the fact that I am allergic to most artificial sweeteners & even the low cal “natural” alternatives give me migraines. Because they are deemed “safe” manufacturers are not required to highlight their use in ingredients & often hide them using alternative names or even an E number. Worst of all, they won’t accept any claim of allergy as genuine, but when a doctor witnessed the reaction first hand (to a drink that did not list the sweetener on the label – but was later revealed to contain sweeteners) there was no doubt in their mind.
Also, with the increase in use of sweeteners our right to choose has been taken away. I have several friends (none of which are overweight & one is a dental nurse) that don’t WANT to have artificial sweeteners, but our choices are being reduced. There are music venues & restaurants that don’t even sell the full sugar drinks, only diet. And despite specifically ordering FULL FAT COKE, I’ve been given the sugar free variety numerous times – ruining my night/meal out.

Rach May 8, 2019

Thank you for a concise and unbiased review.

Matt April 11, 2019

I love all the people on here saying they “stay away from anything artificial”.
They want to keep things 100% natural, like back 200 years ago, when people lived to an average ripe ole age of 32……. hahahahaha.