If your mouth has ever watered and your stomach has ever grumbled just from eyeing a picture of a big slice of cheesecake, here's your explanation: Just looking at pictures of fattening foods is enough to make us hungry, a new study shows.
Research presented at the annual meeting of the Endocrine Society shows that seeing high-calorie items stimulates the appetite control center, which then makes us crave food.
The finding applies to everyone, considering "the current environment is inundated with advertisements showing images of high-calorie foods," study researcher Dr. Kathleen Page, M.D., an assistant professor at the University of Southern California, said in a statement.
The study included fMRI brain scans of 13 young Latina women who are obese. The researchers said they chose this demographic to be participants because they have a higher risk of obesity.
The researchers showed each woman photos of a high-calorie foods and low-calorie foods, and then non-foods. After looking at each category of photo, the women were asked to rate how hungry they were for sweet or savory food items.
For the study, each of the women drank 50 grams of glucose -- the same amount that's in soda -- as well as 50 grams of fructose halfway through the brain scans, to evaluate the effect of sugar on appetite.
The researchers found that after looking at the high-calorie food photos, the study participants' brain regions linked with appetite were activated. Meanwhile, these regions weren't activated when they looked at the photos of non-food items. Looking at the pictures of the high-calorie foods was also linked with a greater reporting of craving sweet and salty foods.
In addition, the brain region's activity levels were higher after drinking the glucose and fructose beverages -- it was the highest after fructose consumption.
Recently, a study presented at the annual SLEEP 2012 conference found that sleep deprivation could also trigger junk food to activate the brain's reward centers, TIME reported.
"The results suggest that, under restricted sleep, individuals will find unhealthy foods highly salient and rewarding, which may lead to greater consumption of those foods," study researcher Marie-Pierre St-Onge, of St. Luke's Roosevelt Hospital Center and Columbia University, told TIME.