- Published on Tuesday, 28 June 2011 16:49
Diet soft drinks can actually make people fatter, say scientists.
Reaching for the Diet cola is a bad idea for those trying to cut calories - because it may make you want to eat more, according to two studies.
Artificial sweeteners could be to blame, as they were shown to increase blood sugar levels over time, and researchers believe they could also actually trigger the appetite.
In one study that followed nearly 500 people, those who drank any amount of the soft drinks each day had 70 per cent bigger waists after a decade than those who drank none.
And those who drank two or more a day had roughly a five-fold increase - almost two inches around the girth, according to the findings presented at a diabetes conference in San Diego.
Those differences were seen even after accounting for other factors such as age, education, diabetes, smoking and physical activity levels.
Epidemiologist Professor Helen Hazuda said: 'If you compare people who consume no diet sodas to those who consumed any, there was a dramatic difference.'
Abdominal obesity is considered particularly dangerous - linked to a host of medical problems such as diabetes, heart disease, gallbladder disease and breast cancer.
The researchers wrote: 'These results suggest that, amidst the national drive to reduce consumption of sugar-sweetened drinks, policies that would promote the consumption of diet soft drinks may have unintended deleterious effects.'
And while the researchers at The University of Texas Health Science Center San Antonio can't conclusively say diet drinks cause those expanding waistlines, the latest paper, which saw 500 people aged 65 yo 74 studied, adds to a growing pile of studies that link the two.
In a separate study reported at the same meeting, artificial sweetener was added to the diets of mice bred to be prone to diabetes.
After three months, the animals fed the artificial sweetener had higher blood sugar levels than mice not fed sweetener.
Three years ago a larger study that followed almost 3,700 Americans over an eight year period found diet soft drink fans gained more weight overall than non-drinkers, with the most extra pounds seen in those who drank the most soda.
Prof Hazuda added: 'Data from this and other prospective studies suggest that the promotion of diet sodas and artificial sweeteners as healthy alternatives may be ill advised. They may be free of calories but not of consequences.'
One theory holds that the body uses taste to regulate hunger, and that artificial sweeteners may be disrupting that mechanism.
Co researcher Sharon Fowler said: 'The thing about artificial sweeteners is that they could have the effect of triggering appetite, but unlike regular sugars they don't deliver something that will squelch the appetite.'
In the other study the mice fed aspartame - a sweetener widely used in soft drinks and other products - had higher blood sugar levels after three months.
Prof Gabriel Fernandes said: 'These results suggest that heavy aspartame exposure might potentially directly contribute to increased blood glucose levels, and thus contribute to the associations observed between diet soda consumption and the risk of diabetes in humans.'
The latest findings will be a blow to the millions who use low calorie artificial sweeteners to help them lose weight.
In America, the number of people who eat foods containing sugar-free sweeteners has doubled from 20 years ago to about 160 million.
Changing lifestyles mean that more Britons are also opting for low-calorie drinks, with them now commanding more than 60 per cent of the market.
In 2007, a study found giving children low calorie food and diet drinks may increase their risk of becoming obese. A team of researchers in Canada suggested children may just eat more to compensate for the lack of calories.
The scientists concluded it was better for children to eat healthy, well-balanced diets with sufficient calories for their daily activities rather than low-calorie snacks or meals.