Why Are You Always Hungry? Experts Share the Top Reasons

Growling stomach, shaky hands, irritable mood? You may know these sensations all too well: You're starving. Hunger, by definition, is a physiological need for nutrients to provide fuel for your body.

There are many different reasons why you might always be hungry, including some typical causes and some lesser-known ones. We talked with nutrition experts to better understand hunger and the science behind it. Some causes of hunger are normal, and others might indicate that you need to check in with your doctor.

What Happens When You're Hungry

"Just like a car needs gas to function, our bodies require food to create energy to survive and thrive. Once the tank is empty, the body needs replenishment," explains Risa Groux, a functional nutritionist. From a biological standpoint, our bodies produce a hormone called ghrelin in the stomach to signal to the brain that the body needs food.

While ghrelin increases before meals and drops after eating, leptin—another hormone made in fat cells—informs the brain that it has adequate energy and no need to consume any food. Sometimes, this process doesn't go exactly as planned. On some occasions, you could eat more than you need and still be hungry.

Common Causes of Hunger

As Groux put it, food is fuel, and our body needs it. And because our bodies are smart and complex, they will let us know when to enjoy a meal. Keep reading for details on common reasons why you may be hungry.

You Haven't Eaten in a While

The most obvious reason your tummy is encouraging you to eat? You haven't had food in a while. "A lack of food over time causes the body to become hungry, which includes discomfort in the midsection, and a feeling of weakness from lack of nutrition," explains nutrition consultant Lauren Minchen.

If you notice you feel sluggish or tired when you haven't eaten, that's your body's natural response to preserving energy. Generally, people can begin to feel hungry three to five hours after they last ate, but it can be longer if you previously consumed a substantial meal.

You Didn't Sleep Well Last Night

Believe it or not, not getting enough shut-eye can cause you to feel hungry. According to Kathleen Winston, Ph.D., RN, from the University of Phoenix, sleep is essential for appetite control. How does that work? While we sleep, our brains and immune systems are strengthened, regulating the hunger hormone ghrelin. For those who don't regularly get enough rest, this hormone is higher, creating increased appetite.

You're Not Eating Enough Protein, Fat, and Fiber

In addition to going long periods without a meal, not eating the right foods can cause hunger pangs. Groux points out that we all need a diet that's balanced with adequate amounts of protein, fat, and fiber in order to feel satisfied.

"Protein regulates ghrelin and leptin, helping us to feel full," explains Groux. "Quality fat helps with the production of leptin to signal that fullness and slow down our digestion."

"A high fiber intake ignites the production of short-chain fatty acids, which causes the body to feel satiated, along with creating a diversity of good gut bacteria in the microbiome," adds Groux. "Soluble fiber, or foods that dissolve in water, tend to decrease appetite and create a feeling of fullness."

You Haven't Had Enough Water

If you don't drink enough water throughout the day, you may find feelings of hunger creeping in, as dehydration can mimic hunger symptoms. This may lead you to believe that you need to eat more, when in reality you may just need to drink a little water for the symptoms to pass. Interestingly, in one study, men who drank 2 glasses of water before a meal ended up consuming 600 fewer calories compared to those who didn't hydrate beforehand.

You Started Exercising More

Regular resistance training has been shown to boost metabolism, leading to increased calorie burn, which can trigger feelings of hunger. So, if you've been consistently lifting weights and find yourself frequently hungry throughout the day, it's likely because your body is expending energy at a faster rate. In this scenario, your hunger is signaling the need to replenish the expended calories by eating more.

You're Only Drinking Smoothies and Meal Replacement Shakes

While smoothies and meal replacement shakes can be convenient for those with busy lifestyles, these beverages may not be completely satiating. As it turns out, liquid calories are digested more quickly than solid foods, meaning that drinking a smoothie or shake may potentially leave you feeling less satisfied after consuming them.

In fact, one study found that participants who consumed liquid meal replacement shakes ended up eating more during their next meal compared to those who consumed a solid version of the meal replacement beforehand.

You're Pregnant or Breastfeeding

Minchen notes that during pregnancy, the body's caloric and macronutrient demand increases to provide proper fuel for fetal growth. "These calories and macronutrients directly fuel the development and growth of the fetal brain and skeletal, muscle, and fat tissue for a healthy baby," says Minchen.

Additionally, breastfeeding places an enormous demand on a woman's body and can make her feel extra hungry. Generally speaking, Minchen says pregnancy requires an additional 300 calories a day, while breastfeeding can require 330 to 400 extra calories daily.

Your Hormones Are Out of Whack

After a night of heavy drinking, do you crave pizza or other carb-heavy foods? This may seem like a normal response, but it's a signal that your hormones are out of whack. Booze inhibits the production of leptin, the fullness hormone, Groux explains.

"Additionally, greater alcohol consumption can diminish the part of the brain responsible for self-control. Therefore, people tend to eat more when drinking alcohol than when not," says Groux.

Also, when you are going through a stressful time, you may turn to sweets or other comfort foods to cope. Stress increases the hormone cortisol, which can increase hunger and promote food cravings.

When Is Being Hungry All the Time a Problem?

There are some medical conditions, both physical and mental, that can create an ongoing sensation of hunger. If you're experiencing any of these symptoms, book an appointment with your doctor to find out the cause.

You Have a Medical Condition

Hyperthyroidism is a condition in which more hormones are present in the body than needed. According to Winston, this can lead to excessive hunger. Other medical culprits that can cause excessive hunger include diabetes, a parasite infection in the intestinal tract, and hypoglycemia.

Fluctuations in blood sugar levels are a prevalent cause of excessive or perpetual hunger. "When blood sugar is elevated, or diabetes is present, appetite tends to increase, as does thirst," says Groux. "This happens because glucose cannot penetrate the cells, and the body rids it through urine. When blood sugars are depleted and hypoglycemia is present, the body will crave food to help regulate blood sugar levels."

You Have a Disordered Eating Pattern

In extreme cases, eating disorders such as anorexia, bulimia, or other body dysmorphia conditions can result in abnormal hunger patterns. Those who have these conditions tend to severely restrict essential calories and other nutrients, creating a growing sense of hunger, Minchen points out. You may also lose your natural hunger signals. If you suspect disordered eating, consult with a professional for an evaluation and treatment.

You're Taking Medication With Hunger As a Side Effect

Certain medications are known to have hunger as a common side effect. Antipsychotics such as clozapine and olanzapine are notorious for causing increased appetite. Additionally, certain antidepressants and corticosteroids can also induce hunger.

However, it's important to note that medications affect everyone differently, so if you suspect that your medication is causing excessive hunger, it's advisable to consult your doctor for personalized guidance and potential adjustments.