Are sweeteners really causing you to gain weight?

Sweeteners linked to weight gain

You may have thought you were doing yourself a favour by swapping sugar for artificial sweeteners in your skinny latte and other food products, but new research says they may contribute to weight gain and major diseases.

The large-scale research by scientists from the University of Manitoba, Canada reviewed data from 37 studies which analysed more than 400,000 people, on average over a 10-year period.  

Clinical nutritionist Stephanie Moore, welcomes the research, as she has always championed eating whole, unprocessed foods, rather than diet alternatives. "Making calories the main criteria for choosing what to eat entirely negates the importance of the nutritional value of a food and what effect that food has upon the body once eaten," she adds.

What are artificial sweeteners?

Artificial sweeteners are synthetic food additives that give food and drinks a sweet taste, and are often marketed as a 'healthy' alterntive to sugar as they contain significantly fewer calories. But the latest research disputes any benefits. 

What foods contain artificial sweeteners?

Many products which contain them are often labelled as ‘reduced sugar’ or ‘diet’ and claim to have weight loss benefits.  

  • fizzy drinks
  • salad dressings
  • cough syrups
  • crisps

Miss Moore, who works at Twenty-five Harley Street day clinic, is adamant that calorie counting – although a concept deeply entrenched in our psyche – is deeply flawed. She stresses that it is not calories that we should be focusing on but how nutritious is the food we’re putting in our mouths.

Sugar substitutes and links to diseases

According to the new study, if you consume sugar substitutes, as well as weight gain, you have an increased risk of developing some of the major diseases:

  • diabetes
  • high blood pressure
  • heart disease
  • obesity

“The results showed a statistically significant association between consumption of artificial sweeteners and higher risks of diabetes and heart disease, as well as increased weight gain,” said the lead author of the study Dr Meghan Azad.

Soft-drink manufacturers argue that artificial sweeteners have been deemed ‘safe’ by health regulators, but the authors of the recent study say more clinical trials need to be done with patients who consume sweeteners.

Why diet foods don’t work

"Those foods marketed as low-fat or diet? Forget them," urges Miss Moore. "They are often low in fat, but highly processed. You have a fat-storing mode and a fat-burning mode. Depending on the type of foods you eat, you are triggering one or the other.Choose carbs and you are turning off all ability to burn fat and driving foods you eat to be stored as fat.

"What calorie counting does do, is offer a sense of control – having tangible guidelines for creating boundaries around what and how much to eat provides great comfort to many who feel out of control of their weight and their food cravings, but this framework only offers a short term solution."

What you should be eating

Sugar is a craving, and usually after a few weeks you can wean yourself off it. Or if you really do have a sweet-tooth, try a little organic honey or adding fruit to your breakfast or substitue fruit for sugar in baking.

“If you want to put your body into a fat-burning rather than fat-storing state, be brave," says Miss Moore.

"Stop buying processed, low-fat, refined foods and start embracing the joy and taste of natural fats, high quality protein and wholesome, fibrous foods and your body will start to very quickly burn fat as it fuels your brain, balances your hormones and give you endless energy,” she enthuses.

A body scan to measure fat

If you are worried about putting on a few extra unwanted pounds, one way to take stock is to have a composition body scan. This helps you to gain an accurate picture of the distribution of fat and lean muscle around your body to the nearest gram – and whether this is healthy – so you can tailor your workout to achieve your goals. Professor David Reid at Twenty-five Harley Street, is one of the UK’s leading expert on DEXA (Dual-energy X-ray absorptiometry) and can provide you with a Body Composition Scan. This can be used to check bone density, but certain models – such as the one he uses, are equipped with ‘Advanced Body Composition’ capabilities. Some fat is harmless, whereas other types wrap around organs and increases your risk of heart disease and diabetes.

Stephanie Moore practices at Twenty-five Harley Street day clinic.  She is author of the book Why Eating Less and Exercising More Makes You Fat £11.99 (Health-in-Hand). Available from good book shops and


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A disorder caused by insufficient or absent production of the hormone insulin by the pancreas, or because the tissues are resistant to the effects. Full medical glossary
One of the three main food constituents (with carbohydrate and protein), and the main form in which energy is stored in the body. Full medical glossary
A substance produced by a gland in one part of the body and carried by the blood to the organs or tissues where it has an effect. Full medical glossary
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Excess accumulation of fat in the body. Full medical glossary
Compounds that form the structure of muscles and other tissues in the body, as well as comprising enzymes and hormones. Full medical glossary
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A type of electromagnetic radiation used to produce images of the body. Full medical glossary