How Food Shapes Your Mood

December 16, 2025

Teenage girl having breakfast in restaurant. She is smelling fresh, warm croissants

Food does more than just nourish your body. What you eat, including how much sugar you consume, also affects how you feel. “It’s important to understand that food is fuel,” says Kathryn Hummer, RD, LD, a clinical dietitian in the bariatric surgery program at University Hospitals. “When you eat the food and nutrients your body needs, it helps you feel better physically, gives you more energy and improves your mood.”

The Gut-Brain Connection

A growing body of research suggests that the gut and brain are connected, sending signals back and forth about how hungry you are, how full, and how nervous, stressed or excited you might feel. The communication between your gut and brain can affect digestion, mood, and cognitive function in positive and negative ways.

“A growling stomach tells the brain, ‘Hey, it's time to eat,’” says Hummer. Other signs that you’re hungry may include:

Trouble concentrating
Feeling tired
Brain fog
Irritability
Headache

The messages the gut and brain send each other can help digestive processes run smoothly when your body is getting the nutrients it needs. But if you’re eating unhealthy foods, your gut may send distress signals to your brain that trigger anxious feelings and low mood or energy.

If you’re stressed out, your brain may send signals to your gut that result in stomach upset or loss of appetite. When your gut experiences stress, it releases lower levels of serotonin and dopamine (the same hormones your brain sends out to stabilize mood and boost pleasure). Studies suggest that this reaction can contribute to symptoms of depression and anxiety.

Sugar and Mood

Eating too much sugar over a long period can disrupt your gut health and increase your risk of depression. Research also indicates that people who consume a lot of ultraprocessed foods and drinks (which tend to be high in sugars, as well as fat, salt and other additives) are more likely to experience gut health and mood problems, particularly depression.

And while sweet treats are okay on occasion, it’s important to limit your sugar intake, or cut back if you know you’re consuming too much. “Check the nutrition labels on packaged foods,” says Hummer. “Baked goods and cereals are often high in sugar – even healthier options like granola can have a lot of added sugar.” She recommends choosing foods with less than 5% of the Daily Value for added sugars, or seeking out sugar-free treats made with sweeteners like Splenda or Swerve. “That way you don't feel overly restricted, but you’re being a little more mindful,” she says.

Hummer explains that whenever you eat or drink something, neurotransmitters are released into your brain that cause different reactions. When you consume sugary, fatty or salty food or drink, it releases feel-good chemicals that make you want more sugar, fat or salt. “But it’s important not to overindulge in these,” she says. “Something that's more sugary, like candy or juice, is going to be absorbed very quickly into your blood, and may leave you feeling irritable, on edge or hungry again soon because you’re not getting the nutrients you need.”

Even a piece of fresh fruit as a snack on its own may not sustain you long enough, says Hummer. She suggests pairing fruit with fiber, protein or a healthy fat, like:

Apple slices with peanut butter
Dried apricots with almonds
Grapes with string cheese
Berries with unsweetened yogurt
Mango with avocado

How to Support Gut Health

A few simple diet and lifestyle choices can help improve your gut health – and your mood. Start with a whole-food, plant-rich diet, like the Mediterranean diet, and make sure you’re eating three balanced meals a day. Hummer also suggests striking a balance between must-have, nutrient-rich foods and the fun, “sometimes” foods you love, making sure you’re getting enough fiber and protein in each meal.

“When you slow down and savor the experience of eating something you truly enjoy, it’ll give you more emotional satisfaction, even with a small amount of that food,” she says. Here are five more tips from Hummer:

Pay attention to how hungry you feel. “Listening to your body and making sure you eat something when you get those signals is important,” says Hummer.
Eat plenty of fiber. “Fiber is essential because it helps regulate gut health,” she says. Eating fiber contributes to regular bowel movements, makes you feel fuller for longer and reduces your risk of stress, anxiety and “hangry” feelings.
Eat vegetables with every meal. Whether they’re raw, cooked, canned, or frozen, starchy and non-starchy veggies are not only full of fiber, but vitamins and other nutrients.
Rethink your drinks. Many people don’t realize how much sugar they consume in their drinks, says Hummer. Try to reduce the amount of sugar you add to coffee or tea, choose drinks made with sugar-free sweeteners, or go for fruit-infused water or sparkling water instead. With alcohol, look for lower ABV options and limit or avoid cocktails made with simple syrup, juices and other sweet mixers.
Practice other healthy lifestyle habits. Staying physically active, getting good quality sleep and managing stress can all help support gut health and mood. These healthy habits will also benefit your overall health and well-being.

When you start eating better and practicing healthy habits, you can start to feel the positive effects in just a short amount of time, says Hummer. “I typically see patients on a monthly basis, and within a month, they notice a difference,” she says. They’re feeling better, sleeping better and have more energy and motivation. “It has a domino effect, and it can happen pretty quickly because they're fueling their body with the nutrients they need, and they're getting that balance right.”