In the sweetener trap

Christiane Fux studied journalism and psychology in Hamburg. The experienced medical editor has been writing magazine articles, news and factual texts on all conceivable health topics since 2001. In addition to her work for, Christiane Fux is also active in prose. Her first crime novel was published in 2012, and she also writes, designs and publishes her own crime plays.

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Sweethearts with no regrets? Those who do not want to gain weight often rely on low-calorie sweeteners. The catch: Cola light & Co still make you fat - or even more so

It's actually a simple calculation: What hardly has any calories cannot make you fat either. And so in times of slimming mania and obesity the sales of sugar-free foods and beverages are booming. In Germany alone, for example, the consumption of lemonades without sugar almost quadrupled between 2008 and 2012 - from 1.2 liters per throat per year to 4.6 liters, according to the Non-Alcoholic Beverages Association.

Thick with sweetener?

However, sweetener consumers do not seem to be doing themselves any good. A French study from 2012 showed, for example, that drinkers of light lemonades with a consumption of 1.5 liters per week have a 50 percent higher risk of developing diabetes. "There is growing evidence that people who use artificial sugar frequently have a significantly higher risk of extreme weight gain, type 2 diabetes and cardiovascular disease," writes Susan Swithers of Purdue University in the journal Cell Press ".

However, overweight people may be more likely to use sugar-free soda anyway, in order not to put on even more weight. Then the weight problems themselves could just as well increase the risk of various diseases, and not the sweeteners like aspartame, saccharin or stevia. In addition, the consumption of artificial sweeteners could have a fatal psychological effect: If you do without real sugar in one place, you may indulge in more of the sweetener in another place, for example a bag of gummy bears.

The unlearned reaction to sweet things

Scientist Swithers now got to the bottom of the matter and evaluated a series of studies. Experiments with rats and mice provided decisive clues. The reason: Since animals have little interest in their figure, psychological factors cannot play a role here. The researchers mixed either sweetener or natural sweetness into the rodents' food. But the rodents that had consumed artificial sweeteners got fat.

One possible explanation for the paradox is that the complex reactions of the body and brain that the sweet taste sets in motion are disrupted by constant consumption of the sweetener. Usually, a sweet taste on the tongue is the signal that the body can count on larger amounts of energy. He adjusts to this with a whole series of physiological measures that promote rapid absorption and utilization of the sugar - for example, the increased release of insulin. If this expectation is constantly disappointed, the signaling effect of the sweet taste fades. The body forgets how to react appropriately to real sugar.

You could think of this as a reverse experiment with a Pavlovian dog. After a while, this would no longer react with saliva flow if the ringing bell was not followed reliably by food. According to this principle, the body of laboratory rodents confused with sweeteners no longer knows when it has absorbed enough energy. As a result, the animals ate too much.

The taste decides

Further studies with human participants showed that it is actually the taste and not direct biochemical reactions that are decisive for the unfavorable effect of the false sweetness. If the artificial sweetness was passed directly into the stomach, there were no typical biochemical reactions, such as the release of the appetite-stimulating hormone ghrelin.

Brain scans from volunteers also confirm that the brain also reacts differently to low-calorie sweeteners. So the reward center only jumps to real sugar - calorie-free sweeteners apparently leave the consumer unsatisfied.

The results shouldn't encourage consuming more real sugar instead of sweetener, warns Swithers. "However, the low-calorie sweetness can intensify the negative effects of real sugar by encouraging excessive consumption." Snacking without regrets remains an unfulfilled dream.

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