Are sweeteners making you fat?

Siski Green / 11 December 2017

It seems like an easy fix – swap your sugar for no-calorie sweeteners... and yet research suggests it might not be so straightforward.



Eat cakes, biscuits and fizzy drinks all without putting on weight! What a wonderful idea. And it’s an idea that’s been promoted by the artificial sweetener manufacturers for decades. They’ve done such a good job of convincing us of the benefits that the business is now worth $97 billion worldwide, a figure that’s on the rise. So why is it that weight loss control is still so difficult and obesity is on the rise? If these sweeteners are calorie-free and we’re all using them, why are we still fat? 

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More and more research points to the idea that we simply can’t fool our brains and bodies into feeling satisfied with artificial sweeteners, which means that by consuming them, we end up wanting more sugar, eating more and gaining weight.

Why sweeteners may make you eat more

Research from Purdue University's Ingestive Behavior Research Center, USA, found that when a group of rats were fed yogurt with artificial sweeteners and another group were fed yogurt with sugar, the artificial sweetener group later consumed more calories, gained more weight and body fat overall. The researchers suggest that this is because by artificial sweeteners change the body’s ability to link high-calorie (sugary) foods to the sweet sensation or taste. You give your body the sweet taste and so it expects high calories but doesn’t get them… which means you feel like you then need to eat more later on. 

Of course, how you, as an individual, respond to those cravings will be the deciding factor in whether you gain weight or not. And for some people – those with diabetes, for example – sweeteners provide a way of being able to enjoy not only the sweet flavour but the textures and other flavours of treats such as cakes, jams and other deserts.

These differences between individuals, say the researchers, may help explains why studies on artificial sweeteners are inconclusive – for some people, dealing with the change in taste/calorie link might be easier than for others, allowing them to maintain a healthy weight.

A study published in The Journal of Physiology found that people who ate artificially sweetened foods when they were hungry or exhausted, were more likely to seek high-calorie alternatives later.

For others, that increased craving for high-calorie foods after using artificial sweeteners might be all too much, resulting in overeating. And, in fact, another study published in The Journal of Physiology found that people who ate artificially sweetened foods when they were hungry or exhausted, were more likely to seek high-calorie alternatives later, suggesting that this kind of ‘relapse’ depends on your emotional and physical state, which might change daily, as well as how strong-willed you are in general.  

How to lose that sweet tooth

So, if sweeteners aren’t the solution, what is? A little self-restraint is what you need. First, start by reducing your sugar intake – whether in sweetener or real sugar form. “If you’re trying to lose weight, I would recommend that you avoid regularly using sweeteners or eating foods that contain them,” says nutritionist Kim Pearson. “After few weeks, you will start noticing and enjoying the natural sweetness of whole foods such as fruits and won’t need to reach for chocolate or biscuits to satisfy your cravings.”

And if you do end up grabbing a biscuit or chocolate, don’t beat yourself up about it. “Doing this can easily turn into an excuse to ‘give up giving up’,” says Pearson. “Instead, remind yourself of your reasons for wanting to cut down on sugar and get back on track the next day.” It’s important to remember that as you reduce your intake of sugar, your body actually gets more sensitive to it – so as time goes on, you’ll find smaller and smaller amounts of sugar are just as satisfying. You may even reach a point where the idea of a large piece of chocolate cake is too sickly to contemplate! 

But if the idea of giving up treats completely is too horrible to contemplate, allow yourself some treats – but make them for special occasions only and perhaps consider a carbohydrate blocker. These work by minimising the conversion of carbohydrates into simple sugars and by doing so help you avoid the usually associated insulin spike, which then later trigger cravings for more sugar. 

How to bring down a post-meal sugar surge

Eating fibre-rich foods before a carbohydrate-rich food also helps – but you need to eat around 10g of fibre to bring down a post-meal sugar surge and that’s quite a lot to get from one serving of veg. So eat a salad before your meal and veggies with it.

You’ll need more than lettuce, though, which doesn’t contain much fibre – try:

  • grated cabbage (1g of fibre per 50g or small handful)
  • celery (1.2g per 115g or handful)
  • 3 florets of cauliflower (1.6g of fibre)
  • 1 carrot (around 2g of fibre)
  • a pepper (2.5g fibre)
  • medium tomato (1.3g fibre)

A bowl filled with these veggies will give you nearly 10g of fibre. Enough to bring down a sugar spike from carbs you eat after by 25%.

Which means you’ll feel satisfied for far longer and are a lot less likely to reach for the snack cupboard, the cheese platter or the biscuit tin after dinner.

The opinions expressed are those of the author and are not held by Saga unless specifically stated.

The material is for general information only and does not constitute investment, tax, legal, medical or other form of advice. You should not rely on this information to make (or refrain from making) any decisions. Always obtain independent, professional advice for your own particular situation.