Increased Appetite? Here Are 8 Possible Causes Of Constant Hunger

Unless you are having trouble gaining weight or have been concerned about losing your appetite for a period of time, having a sudden increase in appetite can be upsetting.

For one, you might have concerns that a sudden increased appetite is indicative of a health issue, and when you are dealing with an increase in your appetite, or you feel hungry all the time, it can be hard to stick with your diet, nutrition, and weight goals.

But, what causes a sudden increase in appetite? What causes appetite increases in people who are not trying to lose weight and haven’t changed their diet? 

In this guide, we will discuss what causes hunger signals or appetite and then focus on common causes of a sudden increase in appetite or gradual but apparent increased appetite over time, along with some tips and strategies to prevent increased hunger, particularly if you are trying to lose weight.

We will cover: 

  • Increased Appetite? Why You Are Hungry All Of A Sudden
  • What Causes a Sudden Increase In Appetite?
  • How to Stop Feeling Hungry All the Time

Let’s get started!

A person with an increased appetite holding a sandwich.

Increased Appetite? Why You Are Hungry All Of A Sudden

An increase in appetite may be referred to as hyperphagia or polyphagia. 

Especially if you are relatively routine with your diet and physical activity, suddenly feeling hungrier all the time or noticing a significant increase in appetite suddenly can be very confusing and alarming.

In general, when you are healthy, appetite regulation in the body is a well-tuned system.

When energy intake is low, or you have increased your exercise or physical activity, hormones that increase hunger signals and stimulate appetite increase.

Higher levels of the hunger hormone ghrelin, trigger your body to seek out more food or more energy-dense calories to replace energy expended through exercise, physical exertion, or in cases where you have deliberately cut your calories to lose weight.

After eating, or if you are in an energy surplus—meaning that you are eating more calories than you are burning—levels of leptin (which is the satiety hormone) increase.

Therefore, it is normal and, actually, a healthy sign that your body is working well if your appetite has increased over a period of time because you have started a new workout program or increased your level of physical activity.

A person eating a salad.

Similarly, even if you are trying to lose weight, if you have cut your calories and been following a weight loss diet, particularly if your caloric restriction is significant, you will likely notice that you are hungrier all of the time or have a bigger appetite.

In both of these cases, your body is simply responding to being in a net caloric deficit, meaning that you are burning more calories than you are consistently eating.

By producing more ghrelin, your hunger will increase, and you will be compelled or motivated to eat more food or eat more frequently throughout the day, or perhaps you will have cravings for energy-dense foods with more calories.

However, if you have an increase in your appetite, even if gradual, but you haven’t changed your exercise habits, daily physical activity, or dietary habits, increased appetite can be a sign of an underlying medical condition such as hyperthyroidism or diabetes, or a response to certain medication you are taking.

Then, there are different causes of a sudden increase in appetite or suddenly feeling hungrier all the time rather than a gradual increase in the amount of food you seem to need to feel satisfied.

Overall, because of the range of causes of appetite changes and some of the medical conditions that can cause a sudden increase in appetite, it is important to consult your healthcare team or work with a nutritionist if you are experiencing a sudden increase in appetite.

A person holding up a knife and fork.

What Causes a Sudden Increase In Appetite?

Here are some of the main causes of appetite changes or an increase in appetite either suddenly or over time:

#1: Starting a New Exercise Program

Increases in physical activity level, particularly if you start running or doing some sort of vigorous cardio or you start weightlifting, can cause you to feel hungrier or even ravenous even after eating.

Exercise burns calories, and if you have not taken into account how many calories you might be burning, you will suddenly feel hungrier.

#2: Dietary Composition

A sudden increase in appetite can occur if you start following a restrictive diet or a particular diet that eliminates food groups or certain nutrients.

For example, if you go on the keto diet, increases in appetite can be a sign of the keto flu, which is a cluster of symptoms that your body might experience when shifting from having a plentiful source of carbohydrates for fuel to only having fat and protein.

Additionally, if you follow a low-carb diet and you have started endurance exercise, your body might be seeking carbs so that you can have glycogen to burn during your workouts.

We have an entire article dedicated to feeling hungry after running and how to deal with appetite after exercise so you can learn more about that topic here.

You may also have increased appetite or increased food cravings if you have nutritional deficiencies in your diet.

A person biting into three sandwhiches.

#3: Dehydration

We often conflate hunger with thirst.

According to research, drinking more water can help burn calories, control appetite, and regulate body systems, all of which can reduce inflammation and support losing weight fast. 

#4: Mental Health Challenges

Depression, stress, anxiety, loneliness, and boredom can all increase appetite or cravings for food.

#5: Insufficient Sleep

Inadequate sleep has been associated with poor blood sugar control as well as an increase in the production of ghrelin, the hormone responsible for appetite, potentially leading to weight gain.

Try to get at least 7 to 9 hours of sleep every night, which is the recommended amount for adults, to help control your appetite and regulate your hormones.

A sign that says hungry.

#6: Medications 

A side effect of certain medications (such as corticosteroids, cyproheptadine, hormonal contraceptives, and tricyclic antidepressants) is an increased appetite.

#7: Medical Conditions 

Certain medical conditions may increase appetite, such as diabetes, hyperthyroidism, Graves’ disease, hypoglycemia, bulimia, and malabsorption diseases like celiac disease and Chrohns or a parasite that is causing chronic diarrhea or absorption issues.

#8: Hormonal Changes

A difference in a sudden increase in appetite female vs male cause is usually hormonal.

A sudden increase in appetite in females can be due to pregnancy, premenstrual syndrome (PMS), a sign of polycystic ovarian syndrome (PCOS), or hormonal swings during menopause or perimenopause.

A person holding a knife and fork in front of an empty plate.

How to Stop Feeling Hungry All the Time

Treating increased hunger or “how to fix sudden increased appetite” really depends on the underlying cause of the appetite increase.

The first step in trying to regulate your appetite and rule out potential medical causes of increased appetite is to take an audit of your caloric balance.

In other words, are you eating enough calories to support your activity level and body weight?

According to the Centers for Disease Control and Prevention, healthy fat loss should not exceed 1-2 pounds per week for most people, which means that you should only be generating a caloric deficit of 500-1000 calories per day at most.

Use an online calculator to estimate your caloric needs.

Are you trying to lose weight, so you have been eating too few calories, are missing key nutrients, and/or practicing intermittent fasting and not eating frequently enough?

Have you started a new exercise program or started walking or running regularly?

Two women eating a plate of hamburgers.

Have you started lifting weights?

You might be burning more calories per day than you were previously or than you thought you were, and your body simply needs more energy.

If you determine that you are in a good caloric balance or not in a significant caloric deficit that warrants an increase in appetite, it’s time to consider some of the other causes, such as medications, health conditions, depression, anxiety, loneliness, stress, and diet composition itself.

Consider if you have concurrent symptoms with your sudden increase in appetite, such as changes in weight, frequent urination, constipation or diarrhea, nausea, bloody stool, weight gain, weight loss, changes in menstruation, etc.

Make sure to note all of your symptoms.

In cases where appetite increases don’t seem to be a product of exercise/diet changes, it is best to work with a doctor, nutritionist, and/or mental health provider who can help you develop an effective treatment plan to help you feel your best and regulate your appetite.

For ideas about energy-dense snacks, if you are struggling to eat enough calories, check out our guide to healthy foods for weight gain here.

A plate full of nuts.
Photo of author
Amber Sayer is a Fitness, Nutrition, and Wellness Writer and Editor, as well as a NASM-Certified Nutrition Coach and UESCA-certified running, endurance nutrition, and triathlon coach. She holds two Masters Degrees—one in Exercise Science and one in Prosthetics and Orthotics. As a Certified Personal Trainer and running coach for 12 years, Amber enjoys staying active and helping others do so as well. In her free time, she likes running, cycling, cooking, and tackling any type of puzzle.

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