Scientists have found that the sugar substitute, Aspartame, may cause weight increase.  Studies have found that this ingredient may induce hunger leading to an increased intake of food, resulting in weight gain.

Medical News Today recently reported that research has shown that even at FDA-recommended levels, saccharin and aspartame can cause increased hunger. Dr. Richard Hodin from the Massachusetts General Hospital Department of Surgery led the said a study and suggested that aspartame's metabolite may play a role in this mechanism.

Hodin's group identified that phenylalanine (a byproduct of aspartame) inhibits a gut enzyme, intestinal alkaline phosphatase (IAP). IAP is known to help prevent metabolic syndrome in mice. Since aspartame inhibits IAP, metabolic syndrome is uninhibited. Metabolic syndrome is an umbrella term for conditions like diabetes mellitus II, cardiovascular disease (like hypertension) and obesity.

"We think that aspartame might not work because, even as it is substituting for sugar, it blocks the beneficial aspects of IAP," Hodin said.

In their 18-week study, two sets of mice were fed a high-fat diet. One group received aspartame in their drinks and the other did not. The aspartame group recorded higher weight gain and higher blood sugar levels than the other group.

Hodin said, "There has been some evidence that they (artificial sweeteners) actually can make you more hungry and may be associated with increased calorie consumption. Our findings regarding aspartame's inhibition of IAP may help explain why the use of aspartame is counterproductive."

An earlier study by Brazilian scientists published in the journal, Apetite (vol. 60, pp203-207), compared the effects of nonnutritive sugars, saccharin and aspartame, to sucrose in a study on rats. They found that, given the same amounts and caloric intake of these three sugars, those that received the nonnutritive ones gained more weight during the 12-week course of the experiment. The study suspected that fluid retention may have been involved in this.

Previous reports also point out that the intake of aspartame can cause weight gain by also fooling the brain's sweet sensor by giving the sweets without the calories.