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The Truth About Sugar and Sweeteners

The research on sweeteners isn't as comprehensive as I'd like yet. Only Aspartame, Saccharin and Sucralose have really been studied properly, and most clinical studies only include these sweeteners. Are they all equal to, or as bad as each other? I'll break it down for you:

The debate about the sugar tax is back in the headlines, which got me thinking, is sugar as bad as people say, and would artificial sweeteners be a better option? Every office and kitchen cupboard usually has a mixture of sweetener packets, claiming to do the same job as sugar but without the calorie hit. This promise can seem too good to be true, especially with the regular media articles telling us that diet sodas are just as bad, if not worse, as their full fat equivalents, and the other articles telling us that sweeteners can cause cancer. So, where does the truth lie between the marketing hype and the damning news articles?

Sweeteners do have benefits. For a start, they are zero-calorie, and allow people to consume versions of their favourite foods and beverages without adding to their daily sugar count. Minimising calories like this makes more room for additional proteins and healthy fats, while making sure you don't feel like you're missing out on that sweet hit. This makes sticking to a diet much easier for many people!

The research on sweeteners isn't as comprehensive as I'd like yet. Only Aspartame, Saccharin and Sucralose have really been studied properly, and most clinical studies only include these sweeteners. Are they all equal to, or as bad as each other? I'll break it down for you:


This sweetener, probably the one most people have heard of, was approved for use in 1974 after numerous studies proved its safety and benefits. Yet people still worry that it has negative side effects - have you ever been told not to drink diet coke, for example?

This negative hype can be traced back to a few studies in rodents which linked Aspartame to cancers. While these studies are solid, the dose of Aspartame that would be needed to create a similar effect in humans is much larger than anyone could consume in a day! According to the Food Stands Agency (FSA), humans can consume 40mg per kg of bodyweight of aspartame each day. This would mean drinking nearly 20 cans of diet coke, and I've never seen anyone manage that! At reasonable doses, like a can of diet soda per day, Aspartame is perfectly safe.


Sucralose can be found in over 4,000 products including, low-fat diary products, 'light' desserts, and 'reduced-calorie' snacks to name a few. Unlike other sweeteners, Sucralose is actually made from sugar, but our bodies just don't recognise it so it isn't metabolised. This allows it to be zero-calorie. Between 10 and 25 per cent of Sucralose is absorbed into the bloodstream before being filtered out by the kidneys, and the rest is also excreted as waste. The advisable daily intake is set at 5mg per kg of bodyweight, but it is estimated that the average person only consumer 1.6mg per kg. No human trials so far have reported any dangerous side effects, although a few have linked Sucralose intake with migraines, so if you suffer from migraines it may be best to avoid it.


Saccharin has a slightly darker reputation, as the FDA tried to ban it in the late 70s. It to is used as sugar substitute and can found in many 'low-calorie' or 'light' foods including low-calorie jams, jellies or syrups. Similar to Aspartame, studies in rodents have linked Saccharin to different types of cancer. It is important for me to state here that no study has ever shown conclusively that Saccharin causes cancer in humans, a few studies have shown this correlation.

In addition, recent studies have shown that Saccharin has had a negative effect on glucose metabolism in mice and rats. One study in particular (by Suez et al.) grouped evidence from other studies, as well as performing its own tests. The paper was seized upon by the media, potentially causing the uproar about sweeteners that most of us are aware of! How many of you have seen the headlines in the tabloids claiming that diet drinks are the root of the obesity crisis, and are responsible for diabetes?

Despite this paper and the media frenzy surrounding it, there is no conclusive evidence that Saccharin, in normal doses, can cause any harm to humans. It's about on a par with other sweeteners, and furthermore, it's hardly used anymore! Aspartame and Sucralose are far more common.

What about their impact on your diet attempts?

My personal opinion is that sticking to a strict diet plan without eating anything sweet is incredibly difficult, and that having a sweet hit now and again can really help people stay on the wagon. Using sweeteners allows you to have this hit without boosting up your calorie count for the day. In this regard, sweeteners can be really helpful for weight management and adhering to a diet plan!

The scientific studies agree with me. Most studies have found that using sweeteners doesn't impact on your energy intake, or cause people to put on weight. Even better, nearly all studies have found that people who substitute sugars for artificial sweeteners lose more weight than those who don't!

The only reason to worry about your sweetener intake is if you drink more than ten cans of diet soda every day. It may also be best to avoid them if you are pregnant or breastfeeding, and as mentioned above, if you suffer from migraines. Otherwise, I'd go for the sweetener over the full fat version every time!

This article first appeared in SLOAN! Magazine, here.