If You Don't Eat When You're Hungry, This Is What Happens To Your Body

Whether you're skipping meals to cut calories and shed a few pounds or you're simply too busy to sit down for a meal, you should know that this can have consequences for your health. If you're ignoring your body's hunger signals, you might not be getting the nutrients you need to fuel your body. And, if weight loss is your goal, you might actually be hindering your success. 

Forgoing food when you're hungry every now and then isn't likely to have a big impact, but if it's a regular occurrence, you're opening yourself up to nutrient deficiencies, cognitive dysfunction, a slowed metabolism, an eating disorder, and even cancer and a shorter life span. What seems like a harmless habit is actually deceivingly dangerous. Here's what you need to know about what happens to your body when you regularly ignore your hunger signals, and why a regular eating pattern is so important for your health and well-being.

Your energy level drops

One of the main effects of not eating when you're hungry is that it can zap your energy. Food provides essential nutrients crucial for sustaining energy levels. When you go too long without eating, your blood sugar levels decline, creating a shortage of glucose, which is vital for energy production. Glucose serves as the primary source of fuel for your body's various functions, including muscle activity and cognitive processes (via the Cleveland Clinic). As your body exhausts its immediate glucose reserves, a hormonal response is triggered. Stress hormones such as cortisol and adrenaline are released to mobilize stored glycogen and eventually fat to compensate for the lack of incoming nutrients (via the American Institute of Stress).

Your body does this to try to maintain homeostasis, or balance. It's a protective measure to conserve energy. But it also requires a lot of energy. Fatigue sets in as the body grapples with the challenge of generating energy without the normal nourishment it needs. In addition to physical fatigue, the absence of a steady supply of nutrients can lead to difficulties in concentration, as your brain requires a great deal of energy to function properly.

In order to maintain stable energy levels, it's important to give your body regular nourishment. Hunger signals are complex, but usually when you feel hungry, it's because your body is telling you it's time to eat. Especially if it's been a while since your last meal, it's important to listen to your body and have a snack or meal to keep your energy levels up.

You won't get the nutrients your body needs

Your body requires a balanced intake of nutrients, including carbohydrates, proteins, fats, vitamins, and minerals, to function optimally. Eating a variety of foods at regularly scheduled mealtimes throughout the day helps you get everything you need.

When you skip meals, you miss out on essential nutrients. For instance, breakfast often includes cereals or dairy products, which are rich in B vitamins, calcium, and iron. Skipping breakfast, even though you're hungry, can lead to deficiencies in these nutrients, impacting your energy levels, brain function, and bone health. Similarly, lunch and dinner provide opportunities to consume other vital nutrients. Proteins, found in meats, beans, and nuts, are essential for muscle repair and immune function, per a review in The Physician and Sportsmedicine. Fruits and vegetables are key sources of vitamins A, C, and E and minerals like potassium and magnesium. Regularly skipping meals that would include these foods can result in deficiencies in these nutrients.

Over time, skipping meals could lead to more serious nutritional deficiencies, with symptoms such as fatigue, dizziness, poor concentration, hair loss, and brittle nails (via Healthline). It could also lead to conditions like anemia (iron deficiency) or osteoporosis (calcium and vitamin D deficiency).

It's important to maintain a balanced diet with regular meals to ensure your body gets the nutrients it needs to stay healthy. In cases where meal skipping is unavoidable, nutrient-rich snacks or supplements could fill the gap, although they are not a substitute for a balanced diet.

You might get food cravings

When you go a long time without eating, your blood sugar level drops. Blood sugar, or glucose, is the primary energy source for the brain and body. This can make you feel fatigued and grumpy, and it can make you crave foods high in fat and calories. 

These cravings are not just a matter of weak willpower; they are a biological response to an energy deficit. When blood sugar levels fall, the body releases the hormone ghrelin, which increases appetite (via The University of Alabama at Birmingham). At the same time, there's a decrease in leptin, the hormone responsible for signaling fullness. This hormonal imbalance boosts the desire for energy-dense foods. Additionally, when you're hungry, the brain's reward system is activated, making high-calorie foods seem more appealing, which can lead to overeating when you finally do eat.

If you're ignoring your hunger signals in the hopes of trimming your calorie intake, this could backfire. When you feel the hunger coming on, it's a much better strategy to nip it in the bud by having a healthy, calorie-controlled snack or meal high in fiber and protein. This will prevent you from getting so hungry that you chow down on a whole microwave pizza or a pint of ice cream instead.

Your risk of gastrointestinal cancer could increase

You might already know that things like smoking, drinking a lot, and being overweight increase your risk of gastrointestinal cancer. But did you know that skipping meals can too? A 2023 study in the Journal of General Internal Medicine found that people who regularly skipped breakfast were more likely to develop gastrointestinal cancers (including gastric, gallbladder, esophageal, and colorectal) over an average of 5 years. 

One explanation for this is that skipping meals can raise levels of C-reactive protein (CRP), a marker of inflammation. Chronic inflammation can damage cells and DNA, and contribute to cancer growth. Breakfast eaters also tend to have lower body mass indexes (BMIs) and healthier metabolic profiles. Obesity and metabolic problems like insulin resistance are risk factors for various cancers, including GI cancers. Additionally, people who skip breakfast are more likely to smoke, drink alcohol, and be physically inactive, all of which are independent risk factors for cancer. But the study found that the link between skipping breakfast and GI cancer risk remained even after accounting for unhealthy lifestyle choices. This suggests that other, as-yet-undetermined factors are at play.

So the next time you wake up hungry but are in too much of a rush to eat, at least grab a small snack (like some whole-grain toast and fruit) on your way out the door. Better yet, wake up 30 minutes earlier to give yourself plenty of time to make a nutritious breakfast that lowers your cancer risk.

You might develop an eating disorder

While occasionally skipping a meal even though you're hungry doesn't hurt, research shows that frequent meal-skipping could lead to the development of an eating disorder, per a study in Eating and Weight Disorders. Initially, skipping meals disrupts your body's hunger and satiety cues. Deprived of regular fuel, your metabolism slows, and your body interprets this as a threat to survival (via Within). To conserve energy, the brain alters hormone levels, increasing ghrelin, the hunger hormone, and decreasing leptin, the satiety hormone (via a paper in Obesity Reviews). This creates the potential for a vicious cycle: The intense hunger that follows can lead to overeating, which triggers guilt and fuels the desire to restrict again.

When you forgo food even though you're hungry, your focus on food may intensify. Food becomes more than just sustenance; it becomes an object of control, fueling obsessive thoughts about calories, body image, and the "right" foods to eat. This preoccupation can morph into disordered eating patterns (like binging and purging) or restrictive eating, fueled by a fear of weight gain and distorted body perception.

Not everyone who skips meals will develop an eating disorder. However, there's a clear link between the two, especially when coupled with other risk factors like genetic predisposition, social pressure, and mental health concerns. You can greatly reduce your risk by making sure to stick to regular meal schedules and not depriving yourself of food even though you're hungry.

Your metabolism will slow down

Skipping meals may seem like a quick way to lose weight, but research suggests it can actually stall your weight loss progress. Your metabolism is responsible for processing food and transforming it into usable energy. This process occurs constantly, even while you're at rest, and burns calories at a specific rate known as the basal metabolic rate (BMR). Prolonged periods without food trigger a physiological response in which the body prioritizes essential functions like brain and organ function while temporarily reducing energy expenditure in non-critical areas like metabolism (via the Academy of Nutrition and Dietetics). This adaptation conserves energy for survival but comes at the cost of a lower BMR.

Secondly, muscle tissue plays a significant role in metabolic rate. As the most metabolically active tissue in the body, muscles burn a significant number of calories even at rest. However, when your calorie intake drops significantly, the body may break down muscle tissue for fuel, further decreasing your BMR (per Healthline). Skipping meals can also disrupt the balance of hormones that regulate hunger and satiety. Ghrelin, the "hunger hormone," increases, leading to food cravings and potential overeating. At the same time, leptin, the "satiety hormone," decreases, making it harder to feel full and potentially contributing to weight gain in the long run.

A more sustainable approach to weight management focuses on regular, balanced meals and snacks throughout the day. This not only helps you maintain a healthy BMR but also keeps blood sugar levels stable, minimizes food cravings, and boosts energy levels.

You won't be able to think clearly

Fueling your body isn't just about physical energy; it's crucial for optimal cognitive function as well. Skipping meals might seem like a quick way to squeeze in extra tasks, but it can actually hinder your mental performance, making you feel foggy and mentally fatigued. This is because your brain needs a steady supply of glucose, its primary fuel source. In fact, your brain uses about 20% of the available glucose (per an article in Trends in Neuroscience). This sugar powers neural processes essential for everything from memory and attention to concentration and problem-solving (via a paper in Advances in Nutrition). When this constant supply is cut off because you skip meals, the brain starts feeling the pinch.

A 2016 study found that children who skipped breakfast performed worse on cognitive tests compared to those who ate. Similarly, a 2023 study revealed that skipping meals is associated with cognitive decline in older adults (via the Journal of Geriatric Psychiatry and Neurology).

Beyond impacting specific cognitive abilities, skipping meals can affect your overall mental well-being. Research suggests that irregular meal patterns are linked to increased anxiety and depression symptoms (via Nutrients). This can further affect how you feel, think, and complete tasks throughout the day.

It's important to give your body and brain a regular supply of energy so you can think clearly throughout the day. Remember, if you're in a hurry, something is better than nothing. Even an apple on the go is better than an empty stomach.

You may have mood swings

If you've ever felt "hangry " (in a bad mood because you're hungry), then you already know how going too long without eating can affect your mental health. Research shows that irregular meal patterns are linked to increased anxiety and depression symptoms (via a review in Nutrients). This suggests that skipping meals can be a contributing factor to mood swings and emotional instability. Another study showed that children scored lower on mental health assessments (per a paper in the International Journal of Environmental Research and Public Health). This highlights the importance of consistent fuel intake for emotional well-being, even in younger individuals.

There are a few physiological explanations for these results. When you skip meals, your blood sugar levels dip, triggering the release of stress hormones like cortisol and adrenaline (via Henry Ford Health). These hormones can lead to feelings of anxiety, irritability, and even anger. Skipping meals also disrupts neurotransmitters in your brain that are essential for regulating mood. Serotonin, dopamine, and norepinephrine, all crucial for feelings of happiness and well-being, can take a hit when your blood sugar drops. This can lead to feelings of sadness, fatigue, and difficulty concentrating, making even minor challenges feel overwhelming. Additionally, the dip in blood sugar can trigger intense cravings for sugary or high-fat foods, leading to overeating later. This "food roller coaster" of restriction and overindulgence can further destabilize your mood and energy levels.

You might not live as long

You might save some time in the morning by skipping breakfast, but research shows you could be taking years off your life if you do it regularly. According to a 2022 study, skipping meals (breakfast, lunch, or dinner) significantly increases your risk of dying younger from various causes, especially heart disease (via the Journal of the Academy of Nutrition and Dietetics). The study tracked over 24,000 adults for years and found that those who regularly ate fewer than three meals a day had higher mortality rates. 

Per the study findings, eating only one meal per day increased the risk of all-cause and cardiovascular disease (CVD) mortality, skipping breakfast raised the risk of CVD mortality, and skipping lunch or dinner was associated with higher all-cause mortality. While experts note that breakfast offers key nutrients for heart health, missing any meal raises the risk of missing out on crucial vitamins and minerals, potentially leading to unhealthy dietary habits in the long run. 

Interestingly, frequent eating (meals less than 4.5 hours apart) was also linked to an increased risk of all-cause mortality. This emphasizes the importance of a balanced diet with consistent meals throughout the day.

You might have digestive problems

Your digestive system is a creature of habit that thrives on regularity. In fact, one of the ways to stay "regular" is to make sure you don't eat too much or too little. Both can have uncomfortable short- and long-term side effects. 

In expectation of regular food delivery, your stomach prepares acids and enzymes to break it down. When the anticipated meal doesn't arrive, these digestive juices remain unused and can irritate the stomach lining and cause heartburn and acid reflux (via Sanitas Medical Center). This acidic environment can also disrupt the balance of gut bacteria, called your microbiome. This can cause bloating, gas, and constipation, among other things. 

Going long stretches without food can lead to unhealthy food choices later. When you're ravenous after a long break from food, you're more likely to make impulsive decisions and reach for sugary, processed snacks instead of balanced meals. These unhealthy choices can wreak havoc on your digestive system, leading to indigestion and diarrhea, and exacerbating existing conditions like irritable bowel syndrome (IBS).

The consequences of skipping meals aren't just temporary. Chronic irregular eating patterns can lead to more serious problems like gallstones, ulcers, and even an increased risk of colorectal cancer (via research in ISRN Nutrition and the Journal of General Internal Medicine). Additionally, the stress on your digestive system can weaken your immune system, making you more vulnerable to infections and other illnesses.