Sugar on the Brain

Bursts of sugar send a surge through the body that has a major effect on the mind

There is no real separation between mind and body. A biochemical connection keeps the two tightly bound—and too much sugar hurts both. Krakenimages.com/Shutterstock

We crave sweetness, but it’s clear that too much leads to suffering. Large-scale studies show that excess sugar consumption can significantly raise the risk of obesity, diabetes, and heart disease.

Our chronic inflammatory reaction to sugar is one factor behind the proliferation of disease in the body, but the mind also suffers from this inflammatory process.

In addition to Alzheimer’s and other degenerative brain disorders that thrive on chronic inflammation, sugar also affects your mental state. Dr. Teralyn Sell, a psychotherapist and functional medicine practitioner who specializes in brain health, says a lot of her patients’ mood disorders actually stem from a high-sugar diet.

“People like to separate the brain from the rest of the body, but there is a correlation they’ve discovered on inflammation and mental health that needs a lot more press,” Sell said. “When we’re looking at inflammation as one of the root causes of mental health problems, depression, anxiety, and ADHD are the three big ones, but it stands to reason that the inflammatory nature of sugar can actually cause other mental health problems as well.”

One example is a study from the British Journal of Psychiatry that showed a strong link between high sugar consumption and the risk of both depression and schizophrenia. Other research indicates that sugar impairs memory and fuels addiction. 

One large, long-term study published in a 2017 edition of Scientific Reports found that men who consumed 67 grams or more of sugar per day were 23 percent more likely to be diagnosed with depression than men who ate 40 grams or less.

“With a high prevalence of mood disorders, and sugar intake commonly two to three times the level recommended, our findings indicate that policies promoting the reduction of sugar intake could additionally support primary and secondary prevention of depression,” researchers wrote.

In addition to inflammation, sugar influences our mental health by affecting our neurotransmitters—the chemical messengers of the nervous system. Some doctors and researchers even classify sugar as an addictive drug because this refined white crystal triggers the pleasure and reward centers in our brain much like a drug does.

“That’s why people indulge in higher amounts to get the same euphoric, rewarding feeling,” Sell said. “It’s similar to drinking alcohol. You may have started with one drink, but now you’re up to six a night.”

How Much Is Too Much?

Sugar (in the form of glucose) provides the body with quick energy. But lately, we’ve gone way beyond the call of duty. Two hundred years ago, the average American ate about two pounds of sugar per year. Today, we each eat about 152 pounds a year, according to the U.S. Department of Health and Human Services.

This sharp increase in consumption is no mystery. Sugar is cheap, plentiful, and it tastes great. But why are we so blind to the damaging effects? Part of the reason is that they’ve been hidden.

A 2016 article from the Journal of the American Medical Association found that scientists had evidence as far back as the 1950s showing that sugar was linked to chronic health problems. However, the sugar industry buried the unfavorable findings. The cover-up was coordinated by an industry-sponsored Harvard research program in the 1960s designed to cast doubt on sugar’s harm.

Now that we know better, doctors are trying to curb our out-of-control sweets habit. The American Heart Association recommends that adult men consume no more than 38 grams or nine teaspoons of sugar daily, women only six teaspoons, and children even less. The latest draft of the 2020–2025 Dietary Guidelines recommends even smaller amounts for daily consumption: no more than 30 grams of added sugar a day for an adult male.

However, Sell says these numbers fall far below what a typical American actually consumes.

“An average soda is 39 grams. A moderate bowl of cereal is 20 grams. That’s without dumping more spoonfuls of sugar on top of it,” she said. “If the average American is already consuming two to three times the recommended amount, is this why our depression rates are so sky high?

Crash and Burn

Another way sugar messes with the mind is through the inevitable spike and crash it creates in blood sugar. You experience a euphoric sugar high, and then, as your blood sugar plummets, your mood and energy fall with it.

“Eventually in the process adrenaline will start to push, so your thinking brain shuts off and you start doing and saying things you wish you wouldn’t have done or said,” Sell said.”When it happens to a child they have a tantrum, throwing themselves on the ground, yelling, and freaking out.”

How can you tell if your depression, anxiety, or other mental health issues might be sugar related? Sell recommends two simple questions: What are you eating, and when are you eating it?

“I see sugar problems all the time, but it’s the one thing people don’t want to address. It’s the elephant in the room. It’s sad because not everything has to be so complicated,” Sell said. “Are you eating food, or are you just dumping sugar in your mouth?”

Stabilizing Protein

Your relationship with sugar typically starts when you wake up. Many start the day with a sweet bowl of cereal or a muffin for breakfast. But Sell says this can set you up to fail. Her recommendation is to focus on protein.

“Protein helps to stabilize blood sugar which helps keep you out of fight or flight. And protein also provides the building blocks for your neurotransmitters, serotonin, dopamine, GABA, all of them,” Sell said. “You’re fueling your brain’s chemical messengers. They help your body do everything.”

Sell advises her patients to eat protein—such as eggs, cheese, nuts, peas, beans, or even a protein shake—at least an hour after they get up, and with every meal. If you snack before bed, make sure that it has protein, too.

“You’re going to be doing your body a huge favor,” she said. “If we have a snack before bed, it’s usually not a protein snack. It’s usually junk food or alcohol. It’s the reward for the end of the day. Then we try to sleep on that and wonder why our sleep is so bad.”

Of course, even if we strive to avoid sugar, sweet treats have a way of worming their way into our lives, especially during the holidays. If you have trouble saying no to sweets, Sell recommends eating protein proactively to keep temptations in check.

“Make sure your blood sugar is stable before you go to a family function,” Sell said. “At Thanksgiving, for example, a lot of people think that they should not eat all day before because they’re going to have such a big meal. They think they’re going to ‘save room.’ But you’re going to the dinner table in a state of hypoglycemia. You’re likely to overeat and choose the more sugary foods. Stay in the protein throughout the day. Don’t go in completely starving.”