• New research details why we crave fats and sugars in our diets.
• Fat and sugar light up certain pathways in the brain.
• When you have both at once, it can make you eat more than usual.

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Certain foods just taste better than others, and usually, they’re the ones that have sugar and fat—at least in our experience. Now, a new study explains why it can be so tough to resist certain foods that have a lot of these compounds: You’re hard-wired to crave them via a mind-body connection.

That’s the main takeaway from the study, which was published in the journal Cell Metabolism. For the study, researchers analyzed mice and found that there are two separate but parallel fat and sugar-craving pathways. These send signals from the gut to the brain, activating the body’s dopamine reward centers when you have foods like ice cream, cookies, and cake. (Dopamine is a hormone that acts on the brain to make you feel pleasure.)

The study also found that the vagus nerve, which connects the gut and brain, sends information through nerve cells in the gut that make fats and sugars appealing. That can
create a subconscious desire to eat fats and sugars, even if you’re actively trying to avoid them.

This can happen with the pathways for sugar and fat separately, but when pathways for both sugar and fat are lit up, you can feel the urge to eat more than usual, the study found. That helps explain why you can feel full after eating a well-balanced meal, but still find a way to make room for dessert afterward.

The study raises a lot of questions about cravings, plus what you can do about them. Here’s what dietitians think.

Why do we crave fat and sugar?

There are a few reasons. “Cravings for fat and sugar are deeply rooted in evolutionary biology,” says Scott Keatley, R.D., co-owner of Keatley Medical Nutrition Therapy. “Historically, these nutrients were scarce and highly valuable for survival, providing dense energy sources and aiding in storing energy for times of scarcity.”

Now, fat and sugar aren’t scarce, but your body still likes them, says Jessica Cording, R.D., author of The Little Book of Game-Changers. “Sugar is a very quick way of getting energy,” she says. When you have sugar, your body recognizes that it can give you a quick pick-me-up. “If you’re tired, sugar is going to look really appealing because the body thinks it’s a quick hit of energy,” she says.

Fat also creates energy, but it can be stored, Cording says. “Fat provides more calories and, by definition, more energy,” Cording explains. Your body can also crave fat as a way to build up your energy stores, although it probably also has realized that fat tends to taste good, Keatley says.

“These cravings are often more about the brain’s search for pleasure and reward than actual nutritional needs,” he says.

What do sugar and fat do to your brain?

Sugar and fat activate your brain’s reward system, Keatley says. “This activation reinforces behaviors and creates a cycle of craving and consumption,” he says. “Over time, this can lead to changes in the brain’s chemistry and structure, potentially affecting decision-making, self-control, and the sensitivity of the reward system itself.”

Sugar and fats can even serve as reminders of certain memories and attachment to some foods as a child, Cording says. “There is an element of soothing with different foods from a behavioral standpoint,” she says.

But if you eat too much fat and sugar, it creates a loop in your brain, where you constantly crave more of it, Cording says. That can also translate to simple carbohydrates, like pasta and juice, making your body crave quick hits from a variety of sources, Cording says.

What to do if you’re having unwanted fat and sugar cravings

Experts admit that it can be tough to fight these cravings—if that’s something you’re interested in doing. That’s why Keatley suggests:

• Focus on mindful eating. “Pay attention to hunger and fullness cues, and eat slowly to enjoy and savor your food,” Keatley says.
• Try to manage your stress levels. Stress can trigger cravings, Keatley says, so engaging in stress-reduction techniques like exercise, meditation, or hobbies can help.
• Avoid or limit foods you find hard to resist. Keatley recommends limiting how available high-fat and high-sugar foods are around you.
• Try to get seven-plus hours of sleep. “Adequate sleep is crucial for hormone regulation, which can affect cravings,” Keatley says.
• Stay hydrated. “Sometimes thirst is mistaken for hunger or cravings, so staying well-hydrated is important,” Keatley says.
• Ask loved ones for support. It’s easier to fight fat and sugar cravings when your friends and family are backing you up, Keatley points out. “Surround yourself with people who are there for you,” he says.

Cording also suggests looking at the rest of your diet if you’re struggling with cravings. “It might sound counterintuitive, but I often see if someone is eating enough carbohydrates if they’re struggling with cravings,” she says. “Someone who eats very low carb all day long can go nuts with carbs and sugar when 7 p.m. hits because they’ve been white-knuckling it all day. I see that a lot.”

Making sure you have enough protein and healthy fats—which can help you feel fuller, and longer and buffer the breakdown of carbohydrates, can also be helpful, Cording says.

Finally, if you’re really struggling and don’t feel that anything you’re doing on your own is helping, Cording says a registered dietitian can help offer personalized advice.

The bottom line

This study suggests what controls cravings and eating behaviors, and why it can be so tough to resist fatty and/or sugary foods. While more research is needed, the findings can also suggest a future target to help stop overeating at the source, Cording says. “This is fascinating,” she says. “We are learning all the time about the different roles of the vagus nerve and the gut-brain connection. Learning about what makes certain foods irresistible is valuable information.”