WFAEats: Keeping It Sweet And Fat

Jun 16, 2018

In the category of Things That Are Really No Surprise comes a bold new study claiming that humans crave foods that are sweet, fatty, and especially a combination of both. This is not news to those us enjoying a doughnut or a biscuit with jam this morning. Nevertheless, scientists found an interesting tool to use when measuring our desire for these foods: money.  

It’s one thing to pick a pastry from a tray set in front of you, but it’s another to decide which you would buy. A group of subjects viewed pictures of different foods laden with carbs, fats, or a combination of both. Then researchers allotted the subjects a set amount of imaginary money to “purchase” the foods. People overwhelmingly preferred those that were high in both carbs and fats.

Parents who struggle to get their kids to eat fruit or cheese instead of fries and cookies are familiar with the power of this craving, and how early it can begin. Our brains are wired to seek substances that trigger chemical rewards and feelings of pleasure. Carbs and fats together amplify each other; in science, this is called a “supra-additive” effect.

This leads to a uniquely human problem because foods high in both substances are really quite rare in nature. Those deep-fried and chocolate-frosted foods are exactly the ones that can contribute to heart disease, diabetes, and other serious health ailments.

But it’s not as if we consciously set out to make poor choices that lead to bad outcomes.  

This visual abstract shows that foods containing fat and carbohydrate are more reinforcing than equicaloric foods containing primarily fat or carbohydrate. This effect is independent of liking and is reflected by supra-additive responses in the striatum during food valuation. This may be one mechanism driving overconsumption of high-fat/carbohydrate processed foods.
Credit DiFeliceantonio and Coppin et al./Cell Metabolism

Interestingly, we’re pretty adept at perceiving the calorie content in fats (and to a lesser degree, carbs) separately, but terrible when the two are combined. For example, we can understand that devouring a whole loaf of bread or wheel of Brie will lead to caloric overload, and we can usually stop ourselves before we overeat.

However, it’s much harder to resist a gargantuan cheeseburger with a side of onion rings slathered with ketchup, not simply because they taste good – but because we don’t recognize that their caloric content far exceeds what we need. It’s what’s known as a “food valuation” problem.

This is especially unfair to those of us living in the Carolinas. How can we be expected to forego that Bo-Berry biscuit when we can smell them baking as we drive by Bojangles? How can we possibly pass up a Krispy Kreme doughnut when the “HOT NOW” sign is blazing? Those little loaves of cornbread with honey butter at Mert’s Heart and Soul? All of those amazing barbecue places where the sweetness and smoke just melt into the meat?

Think of it this way: The next time you reach for something full of carbs and fat, you don’t have to scold yourself. You can blame your brain. And you can back it up with science – because when it comes to what we eat, we now have proof that we’re going to put our money where our mouths are. 

Amy Rogers writes WFAEats, a fun adventure where we explore all things tasty and tackle the meatier side of the food scene in and around Charlotte.