Saccharin – the first artificial sweetener - was discovered by accident when, in 1879, Professor Ira Remsen from Johns Hopkins University noticed a sweet substance on his hands after experimenting with different chemicals in the laboratory.

Saccharin quickly became extremely popular, mainly due to how cheap it was. It was particularly widespread during World War II, when real sugar was in short supply.

Today, artificial sweeteners are central to the huge market of diet- and sugar-free food and drinks. Their attraction today is not only how cheap they are, but their potential to combat the increasing threat of obesity and its associated health impacts.

Saccharin is over 200 times sweeter than sugar but has zero calories. Does this mean that we should replace all sugar with artificial sweeteners? Or are there more factors to consider?

We asked 8 experts "Are artificial sweeteners better for you than sugar?". The consensus was 63 percent 'likely'. Here is what we found out.

What are artificial sweeteners and how do they work?

Artificial sweeteners provide the sweet taste of sugar but without the calories. There are two broad categories of artificial sweeteners: sugar alcohols and high-intensity sweeteners.

Sugar alcohols are structurally similar to sugars but less readily metabolized, whereas high-intensity sweeteners are small compounds many times sweeter than sugar. The high-intensity sweeteners include saccharin and aspartame.

Even though artificial sweeteners provide minimal to no calories that does not mean they are inert. Artificial sweeteners interact with the T1R-family of sweet-taste receptors in the mouth and gut, which can have metabolic effects.

They may also interact with the bacteria that make up the gut microbiome. Different sweeteners might differ in their effect on the body.

Is there a link between artificial sweeteners and cancer?

Concern that artificial sweeteners could be carcinogenic stems from a 1978 study which found that rats that were fed saccharin developed bladder cancer. Since then, it has been shown that this only happens in rats, and saccharin does not cause cancer in humans.

Not just saccharin, but all of the FDA and EU approved artificial sweeteners have undergone testing both in laboratory animals and data from humans. None of the approved sweeteners have any connection to cancer.

Do artificial sweeteners help you lose weight?

The main attraction of artificial sweeteners is that they can replace sugar. There is a huge amount of evidence to suggest that high sugar consumption is bad for your health. Sugary drinks in particular can lead to weight gain, metabolic diseases, and type 2 diabetes. It follows that swapping sugar for calorie-free sweeteners could lead to weight loss.

Many studies have investigated whether replacing sugar with artificial sweeteners leads to weight loss. A 2018 meta-analysis study, which combined the results of 56 different studies, concluded that in most cases groups of people using artificial sweeteners did not lose more weight than those using sugar.

However, overweight or obese individuals who switched to artificial sweeteners did lose more weight than their sugar-eating counterparts.

Other meta-analyses have also found that, on the whole, switching from sugar to sweeteners has a neutral to positive effect on weight loss. The fact that there is not a clear result may stem from the complexity of these experiments:

1) There are many types of sweeteners, each of which may have different effects on weight loss.

2) Changes in diet other than the switch to sweeteners could have confounding effects. Biochemist from the University of Sydney, Dr Kieron Rooney explains that the whole diet is important because "there is data – in humans – that the co-consumption of artificial sweeteners with other foods may have an interaction effect such that the absorption of energy is altered".

3) It is likely that the impact of sweetener on weight loss depends on the original weight and diet of the individual, a result that was found in the 2018 meta-analysis study.

Some scientists have attempted to explain why, on average, people do not lose weight with artificial sweeteners, and in some cases actually gain weight.

Nutritionist Dr Cornelie Nienaber-Rousseau explains that the effect of sweeteners on the food reward system "may contribute to increased appetite, fuel food-seeking behavior and encourage sugar cravings." She adds that "non-caloric artificial sweetener seems to alter the gut microbiome".

Both of these explanations are plausible, but require more research before we can be sure of their effects.

Epidemiologist Gideon Meyerowitz-Katz summarises that "it's possible that artificial sweeteners might be worse for people than water – although this is something of an open question – but compared to sugar, all indications are that artificial sweeteners are probably a bit better."

No silver-bullet to obesity crisis

Overall, considering that artificial sweeteners are essentially calorie-free, the data on their positive health impacts is perhaps a bit disappointing.

This might explain Professor Jennie Brand-Miller's observation from the University of Sydney that "the prevalence of obesity and overweight have tripled in [the last 50 years] despite the popularity of low-calorie sweeteners and their ubiquity".

On the flip side, there is plenty of evidence that they are safe and not linked to any cancers. Whether they have some other effects perhaps on our sugar cravings or microbiome, remains to be determined.

The takeaway:

Sugar-free alternatives, particularly of drinks, could be beneficial to someone who is trying to lose weight or improve their diet. However, the data suggest that they are not the healthiest option available – whilst a diet drink might be better than a sugary one, water might be even better.

Article based on 8 expert answers to this question: "Are artificial sweeteners better for you than sugar?"

This expert response was published in partnership with independent fact-checking platform Subscribe to their weekly newsletter here.