Sometimes, however, a person may feel as though they are hungry all the time. They may find that they do not feel full after eating, or that the desire to eat continues throughout the day.
A person may be able to reduce their hunger by making dietary or lifestyle changes. However, constant hunger can also be a sign of certain medical conditions that may need treatment.
In this article, we describe 17 possible causes of being hungry all the time.
Hunger is a common challenge for people who are dieting.
People who follow a calorie-restricted diet may feel hunger all or much of the time. Consuming fewer calories than the body burns can cause the body to produce a hormone called ghrelin.
Some refer to ghrelin as the "hunger hormone" because the stomach releases it when the body needs more food.
A low-calorie diet can increase ghrelin production and cause hunger, even after a person has just eaten.
2. High-sugar diet
Many food products and beverages have added sugar, and it may increase a person's appetite.
A 2015 review suggests that eating too much sugar, particularly fructose, can lead to increased appetite. A high-fructose diet may cause the body to produce more ghrelin and affect activity in specific regions of the brain to make a person feel less full.
Research from 2017 also found that consuming a fructose supplement increased the rate of stomach emptying in study participants.
3. Low-protein diet
Some research has suggested that eating more protein can help a person feel less hungry. For instance, a 2015 study from China explored the effect of a high-protein diet in 156 adolescents with obesity.
The researchers randomized the participants to eat either a high-protein or low-protein breakfast each day for 3 months. Both breakfasts had the same number of calories.
The study found that compared with the low-protein breakfast, a high-protein breakfast reduced lunchtime food intake and increased weight loss and fullness in the participants.
In the United States, the Food and Nutrition Board recommend that adult males consume 56 grams (g) of protein per day and adult females consume 46 g.
Eating some protein with each meal or snack, rather than all at once, may help keep appetite steady throughout the day.
Proper hydration is essential for good health. Some evidence also suggests that drinking water can help a person feel full.
For example, one 2014 study investigated the effect of excessive water intake in women who were overweight.
The researchers asked the participants to drink 0.5 liters of water 30 minutes before eating breakfast, lunch, and dinner each day. After 8 weeks, the women had lost weight and reported having decreased appetite.
5. Low-fiber diet
As well as being important for healthy digestion and preventing constipation, dietary fiber may also play a role in controlling hunger.
Another study from 2015 reported similar findings in people who took a maltodextrin fiber supplement.
The Food and Nutrition Board recommend that:
- males aged 19–50 years eat 38 g of fiber daily
- females aged 19–50 years eat 25 g of fiber daily
6. Sleep disruption
Getting enough sleep can help support healthy hormone levels.
Not getting enough sleep can disrupt the body's natural hormonal balance, which may increase feelings of hunger in some people.
A small study from 2016 found that men who restricted their sleep had higher ghrelin levels and ate more than those who slept normally.
Some people may confuse boredom with hunger, causing them to eat more.
A 2015 study found that feeling bored can prompt a person to seek rewarding behavior, such as eating.
8. High-salt diet
According to the American Heart Association (AHA), the average person in the U.S. eats more than 3,400 milligrams (mg) of sodium daily, most of which comes from processed foods.
The AHA recommend that people should consume no more than 2,300 mg of sodium per day, but ideally, most adults should aim to consume under 1,500 mg daily.
However, salty foods may affect more than just heart health. Some research suggests that high salt consumption may cause a person to eat more.
For example, a 2016 study involving 48 healthy adults found that participants who had a high-salt meal ate more food than those who had a low-salt meal.
Some medications can affect the body's metabolism and hunger signals. Certain antidepressants, antipsychotics, and corticosteroids may cause a person to feel hungrier than normal.
People experiencing significant weight gain after taking a new medication may wish to speak with their doctor. They can advise on coping strategies or may recommend changing the dosage or switching to an alternative medication.
Sudden withdrawal can cause unwanted side effects, so it is important to discuss stopping a medication with a doctor first.
11. Leptin resistance
Leptin is a hormone that tells the brain when the stomach is full. Leptin levels usually rise after a person eats a meal.
Leptin resistance is a condition in which the body does not respond properly to leptin. This may result in a person not feeling full after eating a meal. Many individuals who are overweight or obese develop leptin resistance, which can make them feel hungry more often.
Research has also linked emotional stress to problems with appetite control. One 2015 study found that people experiencing stress due to marital issues had higher levels of ghrelin and a poorer-quality diet than those in more stable marriages.
13. Artificial sweeteners
Manufacturers add artificial sweeteners to a range of products, including diet sodas and sugar-free or low-sugar foods. The use of these sugar substitutes can help reduce a person's overall sugar intake.
However, some animal studies suggest that artificial sweeteners may increase appetite. For instance, a 2016 study found that a diet sweetened with sucralose, a popular artificial sweetener, promoted hunger in fruit flies.
14. Alcohol consumption
Drinking alcohol may cause hunger.
Drinking alcoholic beverages can make a person feel hungry.
Research from 2017 suggests that the link between alcohol and overeating may be due to the effect that alcohol has on hunger signals in the brain.
In a 2015 study involving 35 women, researchers reported that consuming alcohol prior to a meal made participants more sensitive to food aromas and caused them to eat more.
Women who breastfeed require extra calories to produce milk, which might cause their appetite to increase.
The American College of Obstetricians and Gynecologists recommend that women who are breastfeeding consume an extra 450–500 calories per day.
16. Overactive thyroid
The thyroid is a small gland located in the front of the neck. It produces hormones that control metabolism and how the body uses energy.
An overactive thyroid, or hyperthyroidism, can cause a wide range of symptoms, including increased hunger.
Other symptoms of hyperthyroidism may include:
- a swollen neck
- weight loss
- feeling hot
- irritability, nervousness, and mood swings
- more frequent urination
A doctor can usually diagnose hyperthyroidism with a physical exam and blood test. Treatment options include medications, radioiodine therapy, and thyroid surgery.
17. Type 2 diabetes
Persistent hunger can be a symptom of type 2 diabetes. Without treatment, diabetes causes glucose to stay in the blood instead of going into cells, which use glucose as a source of energy. This can make a person feel tired and hungry.
Other symptoms of type 2 diabetes can include:
- increased thirst
- more frequent urination
- vision problems
- slower healing of cuts and wounds
- unexplained weight loss
People with symptoms of type 2 diabetes should see a doctor for an evaluation. A doctor can often diagnose diabetes with a simple blood test. Treatment options include medications and dietary and lifestyle changes.
A person may feel hungry all the time for a number of reasons. They may be able to reduce this hunger by making dietary changes such as:
- including more protein and fiber
- eating less sugar and salt
- drinking more water
- limiting processed or fried foods
- consuming less alcohol
Increased hunger can be a side effect of some medications. However, it can also indicate a health condition, such as hyperthyroidism, stress, or type 2 diabetes.
People experiencing constant feelings of hunger or unexplained weight loss may wish to consider seeing a doctor.