A new study released in PLOS Biology sheds light on a fascinating aspect of our eating habits: people tend to gravitate toward high-calorie foods, regardless of whether they’re classified as obese or not.
The research, spearheaded by Albino Oliveira-Maia and his team from the Champalimaud Foundation in Portugal, delves into the intricate interplay between our brain chemistry and food preferences.
Brain Chemistry and Food Choices
When we eat, our brains receive signals that inform us about the energy content of the food we’re consuming.
This feedback can significantly influence our food choices, often independent of how the food actually tastes.
Those who struggle with obesity frequently show irregularities in the brain areas responsible for dopamine release.
Dopamine, a key neurotransmitter, plays a vital role in how we experience reward, particularly when it comes to indulging in fatty and sugary foods.
Previous studies have found that after undergoing bariatric surgery for weight loss, individuals often experience a shift in these reward systems, leading to healthier dietary choices, although exactly how this change occurs is still a bit of a mystery.
Study Design and Findings
In this latest research, scientists examined a diverse group of healthy participants, categorizing them into three distinct groups: 11 individuals with obesity, 23 who had recently undergone bariatric surgery, and 27 non-obese individuals.
To gauge food preferences, participants were offered sweetened low-fat yogurt in two variations: one with added maltodextrin, a high-calorie carbohydrate that doesn’t affect the yogurt’s taste or texture, and one without.
They tried these yogurts at home, alternating between the two.
The results were telling; all three groups favored the yogurt enriched with maltodextrin, indicating a marked preference for higher-calorie options, despite all participants rating the taste satisfaction equally.
Interestingly, individuals with obesity showed a consumption pattern similar to their non-obese counterparts when it came to the maltodextrin-infused yogurt.
Dopamine Receptor Levels and Implications
To dig deeper into the neurological factors at play, the researchers utilized radioactive iodine labeling along with single-photon emission computed tomography (SPECT) to measure dopamine receptor levels in the brain.
They discovered that individuals with obesity had fewer available dopamine receptors compared to those who were not obese.
However, the post-surgery patients exhibited a receptor availability comparable to their non-obese peers, and both groups displayed more restrained eating habits.
This suggests that the negative impacts of obesity on brain function might be reversible after bariatric surgery, which can, in turn, alter how much food individuals consume, though not necessarily the types of food they prefer.
The research team was intrigued by the patterns they observed, noting that participants’ attraction to the higher-energy yogurts seemed to occur without any conscious shift in food preference.
There were no significant changes in how pleasant the carbohydrate-enriched flavors were perceived.
Remarkably, this tendency remained consistent among both obese individuals and those who had undergone weight-loss surgery, even with noticeable differences in their dopamine systems.
Source: ScienceDaily