Have you ever tried to satisfy your sweet-tooth with low-calorie desserts, only to find yourself utterly unsated? Now, researchers have determined exactly why the body can't be fooled by artificial sweeteners - a revelation that holds promise for the dieting and diabetic worlds alike.

According to a study recently published in the journal Neuron, artificial sweeteners may be able to trick human conscience, but they neglect to trick the body - specifically, the molecular machinery of the tongue, brain, and gut.

That's because your everyday "zero-calorie" sugar substitutes like Equal (Aspertame) and Sunett (Acesulfame potassium) contain no actual sugar and are virtually non-nutritive. These substitutes, understandably, can be a godsend for diabetics, as very little can chemically elicit a powerful sensation of sweet. This is also what makes them a money-saving, calorie-cutting ingredient for the food industry.

However, experts have long suspected that despite the intense flavors that these substitutes provide, they leave us unsatisfied because the brain knows it didn't get the sugar it craved.

"We knew that the human brain could tell the difference between real and fake sugar, we just did not know how," Monica Dus, a researcher with the University of Michigan, explained in a statement. (Scroll to read on...)

To find out, she and her colleagues looked to fruit flies - sugar-addicts of the insect world who likewise cannot be fooled by artificial sweeteners.

According to the study, the scientists deprived fruit flies of food for several hours and then gave them a choice between intense substitute sweeteners and real sugar. They found that when the flies licked the real sugar, it triggered an exclusive response. A group of six neurons activated and released a hormone with receptors in the gut and brain. This in-turn appeared to fuel digestive processes, allowing the flies to consume more and more of the sugary fuel.

Dus and her colleagues point out that flies and humans share a great deal of genetic information - about 75 percent of the same genes for similar disorders. This could mean then, that flies and humans likewise share the game hormonal response to sugar.

"The bits and pieces are there, so it is really possible," Dus said.

Additionally, the six neurons identified in fruit flies are in roughly the same spot in humans, which removes an immense amount of guesswork. Still, there's plenty more work to do, including identifying and mapping out the response in humans, and even figuring out how to elicit it alongside the pseudo-sweet sensation that substitutes provide.

And even then, will it be enough to keep the brain and body fooled? That too, remains to be seen.

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