If you’ve been wondering “Why am I always hungry?”—even after eating a meal—you’re definitely not the only one. Research suggests that about 1 in 4 Americans snack in between meals, multiple times a day. If you feel hungry all the time, you know how frustrating it can be.
But your appetite is influenced by much more than an empty stomach. Everything from your hormones and gut microbiome to your sleep habits and stress levels can affect how hungry you feel, according to Dr. Federica Amati, a medical scientist, clinical nutritionist, and head nutritionist at ZOE, a personalized nutrition program.
“Understanding our appetite and working with our biology is an amazing way to unlock a happier, healthier relationship with food and support our long-term health,” says Dr. Amati. “Most of us don’t need to fight our appetite—we need to reset it.”
Here’s why you always feel hungry, how to tell the difference between true hunger and cravings, and science-backed ways to stay full longer.
What causes constant hunger?
Dr. Amati: Hunger is a complex response that is affected by the foods we eat, our hormones, and the health of our gut microbiome. These systems influence our brain, which is the central control system for hunger and food behavior, which is also influenced by external factors such as food marketing, advertising, and constant exposure to food.
Persistent hunger may be a result of under-eating, but it may also be a result of leptin resistance in obesity. It’s a signal from our bodies that needs to be understood.
If we feel hungry all the time, are we doing something wrong?
Dr. Amati: I think the biggest misconception is that hunger is a bad thing or a personal failure. That’s not true at all. Our hunger drive kept our species alive throughout evolution. Rather than fighting against it, we need to better understand it and work with it.
Are there different types of hunger?
Dr. Amati: Yes. The first is homeostatic hunger. This is your body telling you that you need nutrients or energy. It’s your body’s way of telling you that you’re running low on fuel. If you’re experiencing homeostatic hunger, you might feel sort of hollow and your tummy might rumble. For some people, they might feel tired and get a little “hangry.”
The next type, hedonic hunger, is not a signal that you need more nutrients. It might be triggered by the smell of a bakery as you pass by. Rather than your brain telling you that you need to eat, it’s telling you that you would enjoy it if you did.
Lastly, our gut microbiomes can shape our food preferences, and this is called micro-biota-driven hunger. Our microbes can converse with our brain through the gut-brain axis. The bacterial species that you feed through your diet will thrive. Then, these species, via the gut-brain axis, can influence what foods you crave. So, if you feed your gut microbiome with poor-quality foods, “bad” gut bacteria will multiply, potentially increasing your desire for more poor-quality foods.
A balanced meal that includes whole grains, vegetables, and other nutrient-dense foods can help support longer-lasting fullness.
(elenaleonova via Getty Images)What’s happening in our bodies between finishing a meal and feeling truly full?
Dr. Amati: Satiety (or feeling full) happens in four phases. First is the cephalic phase, which begins before you even start eating. Your brain receives sensory inputs—sights, smells, and sizzling sounds—and anticipates the meal. This signals to your body to get ready for the incoming nutrients.
Secondly comes the gastric phase, which begins as food enters your stomach, physically stretching it to make room. This activates stretch receptors, which provide feedback to your brain, letting you know that you’re getting full.
Thirdly, we have the small intestine phase, which happens about one to one-and-a-half hours after eating. During this part of the journey, cells in your small intestine act as highly sensitive nutrient sensors, detecting the presence of specific macronutrients (mostly proteins and fats). These cells dispatch satiety signals to the brain to let it know you’ve been properly nourished.
Finally, we enter the colonic phase. Often overlooked, this phase occurs two to three hours after eating a meal. As fiber and resistant starches reach your large intestine (colon), your gut microbes ferment them. This fermentation process stimulates the release of satiety-signaling hormones, including GLP-1 and PYY.
Why do many diets fail to make us feel full?
Dr. Amati: Many diets don’t keep us full for very long because they don’t contain enough nutrients and fiber to activate the colonic phase.
Why do I keep thinking about food all day, even after I’ve eaten? Could it be food noise?
Dr. Amati: Food noise is different from genuine physical hunger. Your body doesn’t actually need fuel, yet you are bombarded with persistent, intrusive thoughts about food. This food rumination is not related to whether you’re hungry or not and can be really disruptive in day-to-day life.
What should I eat if I want to stay full longer?
Dr. Amati: In general, it’s best to combine high-fiber, plant-based foods with quality proteins and healthy fats. These foods are nutrient dense and digested slowly, promoting a slow release of energy as you go through your day. So, focus on legumes, nuts, seeds, whole fruits and vegetables, whole grains, eggs, dairy, and fatty fish.
In contrast, refined carbs, which are broken down really quickly, won’t keep you full for long. For some people, they can also cause large blood glucose responses, which can actually increase feelings of hunger.
Can a bad night’s sleep, stress, or even exercise really affect how hungry you feel?
Dr. Amati: All of these factors can make a difference. A lack of sleep can upset our hormone balance, making us feel hungry, often craving energy-dense foods.
Similarly, chronic stress can make us crave those same foods. And because stress can keep us up at night, it creates a vicious circle that is incredibly hard to escape from.
Exercise has well-documented benefits for overall health, including helping to manage hunger. Not only does physical activity reduce stress and help you sleep better, but it also supports healthy blood glucose levels and improves your body’s metabolic response to food.
Your perpetual hungry may actually be a sign of dehydration.
(Anastasiia Sienotova via Getty Images)Can you mistake thirst for hunger?
Dr. Amati: Hydration is an important part of staying healthy in general, and some people can confuse thirst for hunger, so topping up your fluids throughout the day is good advice.
If I’m always hungry, what’s one change I can make today?
Dr. Amati: I think one of the biggest and most impactful changes you can make is to up your fiber intake and plant diversity. Although the official target is 30 grams per day, the vast majority of people in the U.S. don’t get anywhere near that.
At every meal, try to add as many different plants as you can. The fiber slows digestion, keeps your gut microbiome happy, and provides a wide range of super healthy plant compounds.
How do I know if my constant hunger is something to worry about?
Dr. Amati: When it’s disrupting daily life, reducing your ability to concentrate, and makes you feel unwell, it’s worth speaking to a healthcare professional.
Related: Curious about intuitive eating? A registered dietitian explains how this popular eating philosophy can help you reconnect with your hunger and fullness cues.