A study by researchers at Boston Children’s Hospital found new evidence that suggests “food addiction”, a controversial hypothesis on food selection and consumption, may be triggered by foods that have a high glycemic index (GI).
The Study
For their study, researchers gathered 12 overweight or obese men for a crossover examination. Citing other studies that tried to monitor brain activity after comparing vastly different foods like “cheesecake and boiled vegetables,” Dr. David Ludwig, lead researcher for the study, decided he would try to evaluate results based on glycemic index instead of taste.
To accomplish this, researchers made two test milkshakes with similar ingredients, appearance, taste, smell, and calorie count, but with vastly different glycemic levels. One milkshake was classified as a low-GI meal (37%) with slow-acting carbohydrates, while the other was a high-GI shake (84%) with fast-acting carbohydrates. Confirming that the milkshakes were similar in many controllable aspects, researchers said the participants reported no preference between the two shakes.
Each participant was asked to drink one of the two milkshakes. Researchers then monitored the individual for four hours after the meal. After four hours, the participants:
- Had their blood glucose levels examined;
- Received neuroimaging of certain areas of their brain; and
- Were asked to rate their level of hunger.
2-to-8 weeks after sampling the first shake, participants were brought back in and asked to drink the other shake. The same methods were used to collect data following consumption of the second shake.
The Results
Researchers found that compared to foods with a low glycemic index, a meal with a high GI was shown to:
- Increase hunger;
- Decrease plasma glucose; and
- Stimulate certain brain regions four hours after a meal, which is a crucial time point in deciding what foods will be consumed for the following meal.
Ludwig said he believes the evidence supports a link between food choices and the addiction hypothesis.
“We think we have shown for the first time that refined carbohydrates’ biological effects can provoke, independent of calories and tastiness, symptoms related to addiction in susceptible people — those who are overweight or obese,” said Ludwig. “Every single subject showed intense activation in the nucleus accumbens, the area of the brain related to addiction.”
Ludwig added that when the study was adjusted for the preselected regions of brain activity, the results were strongly significant, with “less than 1 in 1000 likelihood that the results were due to chance.” He concluded by saying certain highly processed carbohydrates can “alter brain activity in ways that make us crave them even more.”
Sound Familiar?
If Ludwig’s sentiments sound familiar, you’re probably a regular on this blog. Not too long ago we featured a two-part series on “The Science of the Food Industry”, which examined how a craving develops inside a person’s brain.
In the first installment, we examined how Dr. Pepper brought in a scientist to optimize the taste of their product, and to pinpoint the consumer’s “bliss point” to keep them coming back for more.
In the second installment, Dr. Silverman commented on the addictive nature of certain processed foods like Lunchables that keep kids coming back for more despite their unhealthy contents. In the end, Dr. Silverman compared carbohydrate-dense foods to cigarettes, saying both are addictive in nature.
While it may seem alarming that certain foods can illicit an intense craving for unhealthy food options, people armed with this knowledge can decide to use this information to their advantage. By making smart food choices early in the day, people can avoid certain cravings and be less hungry later in the day.
Related source: The American Journal of Clinical Nutrition, Medscape