May 10, 2015
To watch what you eat, you may have to watch more closely what you drink, and which type of sugar you consume when you're thirsty could be the culprit behind a ravenous appetite.
According to a study out of the University of Southern California, the metabolic effects of fructose and glucose on insulin levels changes the way that we perceive our degree of hunger. Even though both types of sugar contain the same number of calories, fructose lowers levels of insulin and weakens triggers of satiety in the brain.
What's different about the new study is that it tested for appetite levels using functional magnetic resonance imaging (fMRI) to measure the brain's response to images of high calorie foods, comparing these results with what study participants reported about their cravings.
Twenty-four people were given drinks sweetened with 75 grams of fructose on one day and the same amount of glucose the next day. They were asked a series of questions in tandem with fMRI that confirmed a greater desire for pleasure foods like cookies, candy, burgers, and pizza. When asked to choose between a tasty treat now and a sum of money in a few weeks, participants were more likely to say they'd prefer a tasty treat after consuming fructose.
The researchers believe the difference is related to the hormonal response brought about by each sugar, with fructose metabolized in the liver and not circulated in the blood as much as glucose.
Read more at LiveScience.