Do sugar substitutes make you eat more?

Study finds fake sweeteners are making flies fat

Call me a science nerd, but research rocks! How else would we know that fruit flies whose daily diet contains a regular supply of artificial sweeteners will eat 30 percent more calories than their more svelte friends?

According to a recent study, living on a steady stream of sucralose (marketed as Splenda) makes the chemistry of flies’ brains go haywire and tricks them into thinking they’re starving. They fall into a vicious cycle; the more fake-sugar laden food they eat, the more they want.

This goes on until their tiny compound eyes glaze over. They stare aimlessly in the refrigerator, an empty sugar-free ice cream carton under one wing and two sugar-free cookies under another, wondering why their efforts to eat better and lose weight always fail. Well, this part is all supposition, but as a repeat Weight Watchers dropout, I’m pretty sure it’s entirely possible.

Obesity is a serious matter

Humor aside, we know obesity is a risk factor for many serious health conditions, including diabetes, heart disease, stroke and cancer. According to the Centers for Disease Control and Prevention, medical care costs for obesity in the United States top $147 billion a year.

As many people struggle to maintain a healthy weight, there is good reason to look at whether artificial sweeteners contribute to weight gain and metabolic disorders. Most of the research on this has involved animals, yet some evidence does point to problems in people.

One important outcome from the fruit fly study is researchers were able to replicate their findings in mice. This is significant because being able to repeat insect results in mammals indicates a similar mechanism might also apply in humans.

The sweetness-hunger link

The fly study team from the University of Sydney in Australia focused on how artificial sweeteners impact hunger signals. In comparing brain activity among flies who consumed sugar and those who consumed sucralose, they found much greater neuron firing among the sucralose group.

Gregory Neely, a geneticist and study author, explained in a STAT News interview that our brains calculate how much we should eat based on calories needed to maintain a sweet/energy balance. Because artificial sweeteners have greater sweetness intensity than sugar, they may confound that calculation and cause overeating.

The study, published in Cell Metabolism, found that flies with a sweet/energy imbalance not only ate more, they also had hyperactivity, insomnia and glucose intolerance. These effects, which are not fully understood but may be linked to insulin, were reversed after sucralose use stopped.

Things to consider

Given that billions of people use artificial sweeteners, research like this might well spark some questions:

  • To lose weight, am I better off eating sugar?
  • Are sweeteners OK in limited quantities?
  • What is the safest low-calorie sweetener to use?

“There are no quick, easy answers,” said Hope Pitman, registered dietitian with Norton Weight Management Services.

The many sugar substitutes available today have different chemical properties, and impacts of their use can vary widely. While the Food and Drug Administration generally recognizes “high-intensity sweeteners” (sugar substitutes) as safe and has established an acceptable daily intake for each of the major types, this information is based on knowledge that may change as more research is done.

In the absence of concrete answers, Norton Weight Management Services specialists say the best approach is to stick with some basic common sense tips:

  • Consume sugar and sugar substitutes in moderation.
  • Aim for a healthful diet of lean proteins, fruits, vegetables and whole grains.
  • Read food labels and be aware of “hidden” risks. For example, low-fat products can contain a high amount of sugar.

Potential negative effects from artificial sweeteners should not be interpreted as a reason to over-consume sugar. The American Heart Association recommends no more than 150 calories a day from sugar for men (37.5 grams or 9 teaspoons), and no more than 100 calories per day for women (25 grams or 6 teaspoons).

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