If losing weight is a component (or the entire focus) of your New Year’s resolution, you can greatly improve your chances of success by eating foods that keep you feeling fuller, longer. A new study into glucose and fructose conducted by Yale University School of Medicine suggests that you would be wise to choose glucose sugar over fructose sugar if this is your goal. That’s because glucose does a much better job of sending signals indicating appetite satiation to your brain, subsequently causing you to feel full, according to the researchers behind the study.

In comparison, eating fructose sugar does very little to contribute to a sense of fullness. While one of the best strategies for losing weight involves a significant cutback in sugar consumption, the study seems to indicate that glucose is preferable if sweets are going to be ingested.

fMRI Scans Reveal Big Post-Meal Brain Differences

During the study, researchers used fMRI (or functional magnetic resonance imaging) scans to examine the brains of 20 individuals, all of whom were of a healthy weight. The scans were performed both before and after the subjects drank a beverage sweetened with either glucose or fructose.

In individuals who consumed a drink containing glucose, the scans revealed a reduction in hypothalamus activity. This is the part of the brain tasked with regulating appetite and processing sensations of reward. However, when these same individuals consumed a drink containing fructose, no decrease in hypothalamus activity was observed.

According to the researchers, the results of the study might indicate that high-fructose corn syrup, and particularly its prevalence in American favorites like soda, sugary cereal and sweet snacks, is a major contributor to high levels of obesity in the U.S.

Pure Fructose is Extremely Rare in the Real World

Not everyone was convinced by the findings of the study. According to Terry Davidson, the head of Washington, D.C.’s Center for Behavioral Neuroscience at American University, the study was limited because processed foods usually contain both glucose and fructose, not exclusively one or the other. Even high-fructose corn syrup, despite what’s suggested by its name, is only 55% fructose, while the rest is made up of glucose. Although Davidson couldn’t argue with the results of the fMRI scans, he said that they have little application to real-world foods. He believes the scans would’ve turned out different had the subjects been fed high-fructose corn syrup instead of pure fructose.

Oregon Health and Science University medicine professor Dr. Jonathan Purnell also found the study problematic in that it looked at how different types of sugar influenced brain activity, but went no further. Dr. Purnell believes the study would’ve been more meaningful had it looked to determine whether subjects actually consumed more food after eating fructose as opposed to glucose. In other words, simply having the urge to eat more doesn’t lead to weight gain, unless that urge is acted upon.

At this point, the researchers and their peers agree that more research is needed to determine how various types of sugars interact with appetite levels and obesity.

Glucose and Fructose – The Bottom Line

A recent study by Yale University School of Medicine suggests that eating glucose sugar leads to a feeling of fullness and appetite satiation, while eating fructose sugar does not. Other experts argue that the majority of processed foods contain some combination of these two sugars and not just one or the other, reducing the significance of the study.

The full text of the glucose and fructose study can be found online in the Journal of the American Medical Association.