What Happens to Your Body When You Skip Breakfast

Rise and dine … or not? Find out what happens when you miss out on the first meal of the day.

Reviewed by Dietitian Jessica Ball, M.S., RD

Passing up the pancakes or surrendering the cereal bowl is a common practice: nearly 25% of U.S. adults skip breakfast daily, according to data from the American Journal of Clinical Nutrition. Lack of hunger and pursuit of weight loss are some reasons why people may bypass breakfast.

Breakfast is the morning meal that breaks your night-long fast, which is extended for people who skip breakfast. It’s normal for your blood glucose (aka blood sugar) levels to dip while fasting, which can bring on consequences of regularly skipping meals like low energy, mental fog and intense food cravings.

Consistently missing breakfast without any plan for what and how you’ll eat during the rest of the day might drive you away from your health goals instead of toward them. “Skipping breakfast isn't just about feeling hungry; it's a missed opportunity for nourishing your body and mind effectively,” says Claire Rifkin M.S., RDN, an NYC-based dietitian and founder of a private practice specializing in women's reproductive health. This article will dive into what happens to your body when you skip breakfast, according to health experts.

What Happens to Your Body When You Skip Breakfast

Skipping breakfast may lead to many short- and long-term effects, and here we’ve outlined some that can affect your physical and mental health and overall well-being.

You Might Sap Your Energy Levels.

“Upon waking in the morning, you‘ll have lower blood sugar levels, and if you remain in this state for an extended period, you may experience fatigue or brain fog,” says Marcie Vaske, M.S., LN, CNS. Why eat breakfast regularly? Simply put, our brains rely on glucose to work optimally, according to a 2021 book, Recent Developments in Applied Microbiology and Biochemistry. And where does glucose come from? Primarily carbohydrates! More than likely, your breakfast meal will have a supply of carbohydrates to help maintain healthy blood sugar levels for the energy boost, mental focus and brain power you need.

You Could Throw Off Your Hormones.

Going too long without eating can drop your blood sugar levels and may also throw your hormone levels off course, according to the Endocrine Society. It starts with cortisol, a stress hormone. “Cortisol greatly impacts your mood, your stress response and how you respond to daily tasks and situations. Generally, cortisol levels are higher when you wake up and decline as the day goes on. Eating a morning breakfast can help manage these levels and stress, giving you a mental boost to take on the day,” says Laura Purdy, M.D., M.B.A., a board-certified family medicine physician.

Over time, a disruption in your hormone balance may also impact reproductive health and menstruation, according to Rifkin. “You can support and stabilize these hormonal levels with consistent and nutritious morning meals,” says Rifkin.

Related: Hormones & Our Health: How What We Eat May Affect How They Work

You May Feel More Moody or Anxious.

Naturally, if your hormones are out of whack, you may feel “off” or be prone to mood swings.

But before you go down a research rabbit hole, consider how you’ve been eating lately and whether you’ve missed breakfast.  A 2020 study of 21,972 college students in Diabetes, Metabolic Syndrome and Obesity found regular and irregular breakfast skipping was linked with low happiness, depression and post-traumatic stress disorder.

“When persistently high, cortisol levels are associated with anxiety and depression,” says Rifkin. The good news? Breakfast is an early opportunity to nourish your brain and mental health. “A lack of brain-supportive nutrients, like omega-3 fatty acids and B vitamins, are connected to mood disorders, and breakfast foods can supply these. A nutritious breakfast is more than just physical fuel; it's a critical component in maintaining mental and emotional well-being,” says Rifkin.

You Could Have More Cravings.

While skipping out on breakfast often happens in the morning, it can have a lasting effect for the remainder of the day. “Many breakfast skippers experience more intense cravings later in the day, as their body tries to play catch-up for nutrients they may have missed,” says Melissa Mitri, M.S., RD, a nutrition writer and owner of Melissa Mitri Nutrition.

Your body may seek quick energy sources, which may appear as cravings for chips or baked goods, which can perk you up but leave you hungry shortly after. Everyone gets cravings, but skipping meals can put you in a desperate position where you’re so hungry you’ll eat anything that’s around, even if it’s not consistent with your health goals.

Eating a breakfast that incorporates protein-rich foods can help curb cravings and balance your blood sugar levels. In a 2018 study in Current Developments in Nutrition, consistently eating a high-protein breakfast reduced unhealthy snacking and appetite and increased satiety compared to breakfast skipping. “A balanced breakfast sets a stable foundation for appetite regularity and consistent healthy eating throughout the day,” says Rifkin.

You May Harm Your Heart Health.

Missing meals may be dangerous in the long term, even to the point of harming your heart, and multiple studies back this up. A 2019 meta-analysis in the American Journal of Cardiology found that skipping breakfast was associated with an increased risk of heart disease. This may be related to the metabolic effects breakfast skipping has on blood sugar levels, overeating later in the day and the connection between breakfast skipping and other poor lifestyle habits that may promote heart disease. One 2020 review in Obesity found breakfast skippers were more likely to have higher low-density lipoprotein (LDL) cholesterol than breakfast eaters in the short term. LDL is a type of cholesterol that may contribute to heart attack and stroke risk.

“An American Heart Association study dove into a lot of research around skipping breakfast and the impact on cardiac health and other conditions. Although research isn’t fully clear on the impact because many factors cause chronic illness, it seems those who eat breakfast and regularly timed meals have a healthier cardiac profile than those who don’t. What's most important is the mindset and attention to the types of foods you're eating, getting quality nutrients in your diet, and consistently engaging in healthy lifestyle habits,” says Maggie Berghoff, a functional medicine nurse practitioner, wellness entrepreneur and founder of DetoxDaily.

You Might Slow Your Metabolism.

Some people regularly avoid breakfast in hopes of losing weight, but it may instead hinder weight loss by affecting healthy metabolism. “Without breakfast, the body goes looking for energy elsewhere, pulling reserves from our fat and muscle tissue. This requires energy to do! As a result, other processes slow down to conserve energy and allow it to route toward survival. As a result, metabolism slows down to allow this conservation of energy to happen, decreasing energy levels and storing any reserves in fat tissue for later need,” says Stephanie Darby, RD, a functional nutrition dietitian. Darby describes your body’s survival mechanism that happens when it’s not sure when more food will come. So, eating breakfast is a healthier option for more sustainable weight loss and better metabolic health.

Related: The #1 Habit to Break for Better Metabolic Health, According to Dietitians

Does Skipping Breakfast Help You Lose Weight?

Breakfast skipping may help you lose minimal weight in the short term, but the practice is far from sustainable and can even backfire. According to a 2022 study in Nutrients, skipping breakfast was related to insulin resistance and weight gain. On top of that, it can negatively affect your health overall, which just isn’t worth it. “Obesity, hypertension, diabetes and other health consequences have been linked with regularly skipping breakfast,” says Berghoff.

Avoiding food when you’re hungry can thwart your hunger and fullness hormones, which are there for a reason. These hormones—leptin and ghrelin—help you healthily regulate your appetite, so keeping them at optimal levels is essential. When you're not getting proper signals from these hormones, you may miss a meal when your body needs it the most or overeat low-nutrient foods because you’re famished. Being aware of and honoring your body's hunger and fullness signs is a way to practice mindful eating, and avoid meal skipping.

“When my clients prioritize breakfast, it helps reduce their calorie intake later in the day when it's easy to let healthy habits slip,” says Mitri. She further highlights the connection of eating breakfast to weight. “Research shows those who eat breakfast regularly tend to weigh less. This association is based on several habits, including having a healthier overall diet, better lifestyle habits and activity level,” says Mitri. There are healthier ways to lose weight, where you can enjoy all your meals, even weight-loss supportive breakfasts.

Related: The #1 Weight-Loss Mistake, According to a Dietitian—Plus How to Fix It

Tips for Building a Healthy Breakfast

You can treat breakfast similarly to any other meal and start your day with filling nutrients in mind. “A great breakfast is about the power trio: fat, fiber and protein. This combination is your secret to energizing and keeping your blood sugar happy. An easy example would look like whole-wheat avocado toast with an egg on top. The avocado brings the good fats, the whole-wheat toast is the fiber and the egg adds a source of protein,” says Rifkin.

If breakfast hasn’t been a regular part of your early routine, it can be challenging to start eating it, especially if you’re not hungry in the mornings. “I recommend starting small to get your body used to having some sort of food in the morning. Starting with something that may be more typical of a snack size is usually a good starting point. Your body will eventually send you hunger cues in the morning, making it easier not to skip breakfast,” says Alyssa Pacheco, RD. Pacheo suggests keeping things simple yet satisfying. “A Greek yogurt with some fruit and chia seeds is one example of a simple breakfast that provides a lot of nutrients to start your day off strong,” say Pacheo. Bake up make-ahead breakfasts that can make the choice of whether or not to eat in the A.M. an easy one.

Not a breakfast-food lover? That’s OK, too. It’s totally OK to opt out of traditional breakfast foods. Though atypical, foods like trail mix, black bean and cheese tortillas or salads are high-protein snacks or mini-meals that can help keep you full and fueled as your first meal of the day.

The Bottom Line

Eating breakfast helps give your body the nutrients it needs to sustain your energy, balance your hormones and enhance your mood so you can think clearly and focus. That said, skipping this crucial morning meal is linked to poor health outcomes like blood sugar imbalances and greater risk of chronic diseases. We owe it to ourselves to be in tune with our bodies' nutrient needs by honoring our hunger and fullness cues and eating regularly and consistently.

“Breakfast doesn't have to be elaborate; it can be a simple and satisfying start to the day, promoting overall nutrition and well-being,” says Rifkin.

Read the original article on Eating Well.