According to a recent study published in Nature Metabolism, obese individuals’ brains react to foods differently even after significant weight reduction.
Researchers looked at 60 people over 40; half had been given an obese diagnosis, and the other half did not.
Different solutions containing glucose, lipids, or water alone were directly pumped into participant stomachs on various days to study how the brain reacts to meals in these two groups.
Following the infusion, researchers used functional MRI scans to assess brain activity for around 30 minutes.
They also assessed participant reports of hunger and blood hormone levels.
The findings demonstrated that the reward regions of the brain were appropriately activated in the group of participants who did not have obesity in response to the foods.
On the other hand, participants who were obese did not have these same brain regions activated during the scan.
This result remained unchanged when the scan was repeated 3 months later in obese participants who had lost 10 percent of their body weight through diet.
According to experts, this lack of a reward response may cause overeating and make it difficult to alter eating patterns which may cause weight gain.
Board-certified obesity medicine specialist Dr. Jennifer Ashton said that “This study really, really proves the biological and brain causes are contributions for overweight and obesity are really a real thing.”
Although these results confirm what experts already know to be true—that there is more to weight loss than just willpower—the study’s authors warn that there are significant limitations.
For instance, it might not be generalizable to younger populations because it was only conducted in a small sample of adults over the age of 40.
Furthermore, the differences in the brain may not apply in all situations because the study used a feeding tube to administer the nutrients, which does not reflect how the majority of people actually eat or take into account food preferences.
Experts stress that even in the presence of these changes, it is still possible for someone who is obese to lose weight and keep it off.
Ashton continues by expressing her hope that studies like this one will encourage the development of more specialized treatments for those who are obese or overweight and provide more proof of the effectiveness of some weight-loss drugs, such as Wegovy.
“I think it represents a possibility for target and intervention starting in the brain with those hormonal signals of hunger and satiety, and that’s what a lot of these FDA-approved weight loss drugs are doing.”
