A team of researchers from Germany, Switzerland, and Canada observed that foods that contain both fats and carbohydrates appear to signal their potential caloric loads to the brain through distinct mechanisms. The study participants accurately estimated calories from fat but were very poor at estimating calories from carbohydrates.
Dana Small, the senior author of the study and director of Yale University's Modern Diet and Physiology Research Center, explained that the biological process that is responsible for associating foods with their nutritional value evolved to cautiously determine the value of a food for organisms to make adaptive decisions.
"For example, a mouse should not risk running into the open and exposing itself to a predator if a food provides little energy," said Small.
In order to determine the brain-body mechanisms behind the genetic predisposition for obesity, eating in the absence of hunger, and difficulty losing or warding off excess weight, the research team investigated how the brain responds to food cues.
In the study, the research team recruited 206 adult participants who underwent brain scans while being shown images of familiar snacks that mostly contain fat, sugar, and a combination of fat and carbohydrates. After that, the participants were given a limited amount of money to bid on their first-choice foods.
Results revealed that the participants were willing to pay more for foods that contain a combination of fat and carbohydrates. Furthermore, the combination of fats and carbohydrates stimulated neural circuits in the reward center of the brain more than a favorite food, a possibly sweeter or more energy-dense food, or a larger portion size.
"In nature, foods high in fat and carbohydrate are very rare and tend to have fiber, which slows metabolism," said Small. "By contrast, it is very common for processed foods to have high fat and high carbohydrate loads."
The findings of the study suggest that when fats and carbohydrates are put together, the brain appears to overestimate the energetic value of the food. Scientists think that people's past experience with the nutritive properties of carbohydrates releases dopamine in the brain through an unknown metabolic signal, which appears to help control the kind and amount of food people consume.
Moreover, the research team hypothesized that the activation of fat and carbohydrate signaling pathways at the same time results in an effect that human physiology has not evolved to handle.
Although fats and carbohydrates are needed by the body, eating too much of these can harm your health. (Related: Choose carbs, proteins and fats carefully.) Processed foods are an example of foods that contain both high amounts of fats and carbohydrates. Here are some of the health consequences of excessive consumption of these types of foods:
Read more news stories and studies on unhealthy foods by going to Addiction.news.
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