How the Gut-Brain Connection Affects Your Mood

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Has anyone ever told you that you seem "hangry?" If the word isn't familiar to you, the sensation associated with it probably is.

Can you remember a day when you skipped breakfast, only to overreact to a coworker or snap at your kids before lunch? It's possible that you were having a bad day, but if you hadn't eaten in a while, you were probably just hangry.

Hangry: Definition and Symptoms

So where does the word "hangry" come from? As you might have guessed, it's a combination of the words hungry and angry. Hangry isn't exactly a medical term, but that doesn't mean scientists don't recognize its symptoms.

The connection between hunger and mood is evidenced by blood sugar fluctuations. After eating, blood sugar levels increase, giving us a boost of energy. The food we consume is metabolized into glucose, a form of sugar which is your brain's preferred energy source. If you haven't eaten in a while, your blood glucose levels will go down. For most people, this triggers hunger.

Low blood sugar levels and changes in mood are often linked. The following adjectives may describe how you feel when you're hungry:

  • Aggressive: When you get hangry, you may feel the urge to lash out at friends or loved ones. A study of married couples found that intimate partners were more likely to express aggressive impulses towards each other when their blood sugar levels were lower than normal.
  • Distractable: Low blood sugar is associated with poor concentration. Hangry students may have a harder time paying attention in class; and hangry employees might not be able to focus during a pre-lunch meeting or an important phone call at the end of a long day.
  • Impulsive: Sticking to a balanced eating plan can be tough when you're hangry. Studies have demonstrated that mild hypoglycemia (low blood sugar) triggers a hankering for high-calorie foods in the brain.

Your symptoms of being hangry may vary. Some people get tired. Others become agitated. Mental fogginess and a dip in motivation are common. Regardless of your symptoms, it's helpful to recognize when hunger is impacting how you feel.

The Gut-Brain Connection

When we routinely practice good nutrition, our metabolic processes supply our body and brain with the nutrients needed for optimal function. Unfortunately, hectic schedules and daily stressors can get in the way of eating well. Going too long without food causes additional changes aside from low blood glucose.

"Low blood sugar is the trigger but there are many physiological factors at play," says William Yancy M.D. Dr. Yancy is an associate professor of medicine at Duke University School of Medicine and program director at the Duke Diet & Fitness Center.

Dr. Yancy explains that blood glucose response may be different from person to person. True low blood sugar is a condition called hypoglycemia. This is defined as a glucose level lower than 70 milligrams per deciliter (mg/dL). Furthermore, he states: "Some people may experience symptoms when blood sugar is not technically low if their blood sugar is chronically elevated, or when their blood sugar drops quickly from a high."

According to Dr. Yancy, the main factors are the hormones glucagon and epinephrine (also called adrenaline). These are part of the sympathetic nervous system (SNS). When blood sugar levels are low, glucagon and epinephrine are released.

These hormones strive to bring blood sugar levels back to normal by breaking down either stored carbohydrate or fat. Adrenaline or epinephrine is sometimes called a stress hormone because of the effect it has on the body.

"The SNS and epinephrine cause many of the symptoms of hypoglycemia: shakiness, nervousness, sweating, dry mouth, pallor," says Dr. Yancy. "In addition, hunger, sweating, and tingling are caused by acetylcholine release in SNS nerves." He adds that the central nervous system may also be involved in the process.

When the central nervous systems lack glucose it can lead to confusion, irritability, and even decreased consciousness in severe cases. Dr. Yancy adds that there are other hormones involved, such as cortisol and growth hormone, but they play a lesser role.

Sound complicated? Registered dietitian and nutrition expert Molly Cleary breaks it down into simple terms.

Molly Cleary, RD

"All the symptoms associated with being 'hangry' essentially stem from having low blood sugar, but there are a few different pathways going on. Our brains are dependent on glucose for fuel, so when we haven't eaten in a while, our brains can start to feel a little fuzzy and we may not think as clearly as usual.

This can lead to impulse decisions or a shorter temper. When our blood sugar gets low, it also triggers hormones to be secreted from other organs in our bodies. Some of these hormones play a role in behavior control, and their secretion can make us more aggressive."

— Molly Cleary, RD

Cleary adds that there are certain people that are more prone to getting hangry. "Feelings of hunger and anger are both controlled by genes, and everyone has different genetic makeups. People also express their feelings differently, some people being more open or vocal than others, which can make their response to hanger seem more extreme."

While these brain and body changes may sound dramatic and potentially even dangerous, in most cases they are not. Dr. Yancy says that "severe cases of hypoglycemia only occur in patients taking insulin or sulfonylurea medications for diabetes. In patients who do not take these medications, our physiology will pull us out of the episode."

How to Avoid Getting Hangry

Even if the condition isn't dangerous, most of us would like to avoid getting hangry. After all, who wants to deal with the fallout of snapping at the boss simply because of a missed meal? Luckily, there are ways to prevent this issue.

Cleary says that the best way to prevent hanger is to eat something before getting to the point where you feel hangry. For many people, this means eating smaller portions more than three times per day. "If you know you're prone to hanger, it can help to carry around a small snack to have in a pinch," says Cleary.

Food quality matters as well. Dr. Yancy says that eating a balanced meal plan is important. He suggests planning meals mixed in carbohydrate, protein, and fat. If you start to feel hangry between meals, he suggests consuming a snack that combines all three macronutrients.

Cleary explains, "High carbohydrate meals or snacks such as chips, cookies, or candy can raise our blood glucose levels quickly, but then they may cause crashes later. It's best to choose a more balanced option that contains complex carbs and protein. This may include whole-grain crackers with hummus, banana with peanut butter, or a yogurt with fruit and nuts."

Lastly, if you get hangry often, plan your meals when the symptoms are likely to happen. And avoid drinking too much caffeine, advises Dr. Yancy. Caffeine can exacerbate the symptoms of feeling hangry so it's best not to rely on coffee alone to boost your energy levels.

A Word From Verywell

There is nothing more frustrating than losing control of your emotions. Understanding the gut-brain connection may help you to prevent episodes of anger. If you get hangry often, change your meal schedule to avoid severe hunger or carry healthy snacks to keep your blood sugar steady.

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