Forget about sweet dreams.
People crave fatty and sugary foods when they consume them daily — and the pattern can be hard to break, researchers at Yale University and the Max Planck Institute for Metabolism Research in Germany have determined in new research.
The study, published online Wednesday in the journal Cell Metabolism, found eating a snack high in fat and sugar every day alters the reward circuits in human brains to create lasting preferences.
Participants were divided into two groups and told to continue their normal eating habits, except for one major difference.
Researchers gave one group yogurt high in fat and sugar twice daily for eight weeks, while the other group received a low-fat, low-sugar version.
At the end of the eight weeks, participants were offered puddings with varying fat contents and apple juice containing differing sugar levels and told to rate them for fattiness, creaminess, oiliness, sweetness, desire and satisfaction.
Scientists found the group that was used to eating the yogurt higher in sugar and fat didn’t enjoy the healthier options as much as they had before the study.
The participants also underwent MRI scans to track brain activity while drinking milkshakes, which showed increased activity for the high-sugar, high-fat group, but not for the other group.
“Let’s say a new bakery opens up next to your work and you start stopping in and having a scone every morning. That alone can rewire your basic fundamental dopamine learning circuits,” Dana Small, the study’s senior author and director of Yale University School of Medicine’s Modern Diet and Physiology Research Center, told NBC News.
The authors likened the findings to the effects of addictive drugs, saying exposure to foods high in sugar and fat indicates that habitual factors contribute to obesity — not just genetic and environmental influences, as previously thought.
Small told NBC News the study is the first to show that even small human dietary changes can rewire brain circuits and increase the long-term risk of overindulgence or weight gain.
The findings support a rat study published in January in the Journal of Physiology, which showed that a consistent diet of high-fat and high-caloric foods can change the neurological pathways in your brain, reducing its ability to regulate calorie intake.
While a “brief exposure” of three to five days of fatty foods didn’t appear to affect the pathways between the brain and stomach, the researchers noted the decline with 10 to 14 days of high-fat and high-calorie diets.
Junk food has been linked to depression, with a study recently published in the Journal of Affective Disorders finding rates of depression are significantly higher in people whose diets include large amounts of ultra-processed foods.
According to the CDC, over 41% of US adults are obese, which increases their risk of cardiovascular disease and Type 2 diabetes.