Why foods high in both fat and carbohydrates can be so hard to resist
Why are some foods so hard to resist? Researchers looked at foods that are high in both fat and carbohydrates – a combination that is common in many highly processed snack foods, but much less common in foods found in nature. They wanted to understand whether this combination makes foods more appealing.
Researchers showed people pictures of familiar snack foods. Some were mostly carbohydrates, some mostly fat, and some high in both fat and carbohydrates. The foods contained the same number of calories, allowing researchers to test whether the source of those calories mattered. Participants said how much they would pay for each food while researchers did brain scans to see how the participants’ brains responded.
People were willing to pay more for foods that were high in both fat and carbohydrates than for foods that were mostly fat or mostly carbohydrates alone. Because the foods had the same number of calories, the findings show that it mattered whether those calories came from fat, carbohydrates, or both – not just how many calories the foods contained. Brain scans also showed different patterns of activity across brain areas for foods high in both fat and carbohydrates than for foods that were mostly fat or carbohydrates alone. These patterns were related to how much participants were willing to pay.
Researchers also tested how well people could estimate calories. Participants were more accurate with fatty foods than foods high in carbohydrates or both fat and carbohydrates. This suggests that foods combining fat and carbohydrates may make it harder to recognize how many calories they contain.
The takeaway: Foods high in both fat and carbohydrates may be especially hard to resist. Even with the same number of calories, people valued them more than foods made up mostly of fat or carbohydrates alone. Brain scans also showed different patterns of activity linked to how much people were willing to pay, and people had more difficulty estimating their calories than they did with fatty foods. Together, these findings may help explain why highly processed foods such as cookies, chips, pastries, and other snack foods can be so easy to overeat.
