It’s no accident that you’re quick to forget your dietary needs as you’re reaching for your wallet to pay for a serve of greasy hot chips or a kebab that’s full of fat and carbohydrates.
According to a new German-led study, published in Cell Metabolism today, adults opt to eat processed foods full of fats and carbohydrates because of the effect it has on our brain.
The research shows that foods containing both fat and carbs hijack our body's inborn signals governing food consumption, telling our brain to choose the fatty carby combination food over the carb-laden or fatty meal.
It also suggests that foods with fat and carbohydrate – like most processed foods – reinforce a greater sense of reward than foods of an equal calorie content that contain mostly fats or carbohydrates.
“These results provide the first demonstration that foods high in fat and carbohydrate are, calorie for calorie, valued more than foods containing only fat or carbohydrate and that this effect is associated with greater recruitment of central reward circuits,” the study reads.
...foods with fat and carbohydrate – like most processed foods – reinforce a greater sense of reward than foods of an equal calorie content that contain mostly fats or carbohydrates.
Not only do we derive a greater sense of reward by dining out on hot chips and other processed foods but the study shows we are willing to pay more for the pleasure of doing it.
Researchers from Germany, Switzerland, USA and Canada conducted the study with 206 adults. They scanned the participant’s brains while showing them photographs of familiar snacks containing mostly fat, mostly sugar, and a combination of fat and carbs.
Allocated a limited amount of money to bid on their first-choice foods, the results showed the participants were willing to pay more for foods that combined fat and carbohydrates.
The fat-carb combo also lit up more neural circuits in the reward center of the brain compared to a favourite food, potentially sweeter or more energy-dense food, or a larger portion size.
“Although individuals are very accurate at estimating the energy density of fatty foods, they are poor at estimating the energy density of carbohydrate-containing foods…” the study reads.
The study’s authors also suggest that the response to photos of fatty-carby foods like hot chips or other processed meals might be stronger in obese adults or young people with a healthy weight.
Personal dietary restraint may play a role in being able to exercise self-control and say no to processed foods.
Even still, the study demonstrates that we’re “sensitive not only to the energetic properties and value of food pictures but also to the experience of food decisions where taste and energy density must be considered”.
“These results imply that a potentiated reward signal generated by foods high in both fat and carbohydrate may be one mechanism by which a food environment rife with processed foods high in fat and carbohydrate leads to overeating.”
Not only do we derive a greater sense of reward by dining out on hot chips and other processed foods but the study shows we are willing to pay more for the pleasure of doing it.
The researchers say that perhaps this fat-carb glitch in the human brain may imply that we were not created to indulge on processed foods full of fat and carbs.
Previous work done on animals shows that foods with fat and carbohydrates are preferred over foods individually high in carbs or fats, which guide our food choices. Given unrestricted access to fat and carbohydrates, rodents quickly gain weight.
More research conducted in other parts of the world, with other food items, is needed to conclusively determine the cross-cultural impact of fat-carb laden foods on the brain.
