I think most of us have found ourselves standing in front of the refrigerator in the middle of the night or suddenly craving a cheesy slice of pizza after seeing a commercial on TV—regardless of whether or not you actually feel hungry.
But have you ever stopped to wonder why?
- Why does our brain sometimes feel hungry, even when our stomach isn’t?
- How does our body know when it’s time to eat and when we feel full?
- Why do we suddenly feel ravenous when cutting calories but have no appetite when we’re feeling down?
Let’s break down hunger vs appetite even further to understand the answers to all of these questions.
To help you find information more quickly, this table of contents will definitely come in handy with this article.
What’s the difference between hunger vs appetite?
How many times have you felt hungry without actually being hungry?
If you’re like me, it often strikes when passing by the window of a delicious bakery or after catching a brief whiff of Chinese food when my neighbors order late-night takeout.
There’s definitely a distinction that should be made between “brain hunger” and “stomach hunger.”
Think about it: if you’ve ever been stressed or depressed and totally lost your appetite for a day, that doesn’t mean you weren’t hungry. Your stomach might have been hungry, but your brain not so much.
On the other hand, all of us have probably been suddenly hit by that sudden craving for a snack, even though we just ate a few hours ago and we’re probably not actually all that hungry.
It’s important to distinguish between hunger vs appetite. According to WebMD:
- “Hunger is a normal sensation that makes you want to eat. Your body tells your brain that your stomach is empty. Your stomach tells your brain that it is full. Normally, this feeling causes you to stop eating and not think about food again for several hours.”
- “Appetite is a desire for food, usually after seeing, smelling, or thinking about food. Even after you feel full, your appetite can make you keep eating. It can also stop you from eating even though you are hungry. This might happen when you are sick or feeling stressed.”
Lots of things can affect our “brain hunger” and appetite, including certain medications, physical conditions, metabolic problems, thyroid dysfunction, drug use, psychological issues, and even the diet. The biggest contributors, though, are our “hunger hormones,” ghrelin and leptin.
What’s the role of “hunger hormones” in hunger vs appetite?
- Ghrelin, also known as the “hunger hormone,” is what signals to the brain that you’re feeling hungry. It’s released in the stomach and typically shoots up right before eating, then drops for about three hours afterwards.
- Leptin, on the other hand, is also called the “starvation hormone” or “satiety hormone.” As you can imagine, this is what signals to the brain that we’ve had enough to eat and it’s time to put down the fork.
Ghrelin can be influenced by lots of different factors, but diet has the biggest impact. While diet-induced weight loss typically leads to an increase in ghrelin, certain diets have actually been shown to suppress ghrelin and lead to a loss of appetite.
- A study by Sumithran et. al, for example, found that participants on a ketogenic diet actually had lower levels of ghrelin and a decreased appetite once ketotic.
- A review published in the journal Obesity Reviews noted that high fat diets, high carbohydrate diets, and intake of Psyllium fiber were all associated with a decrease in ghrelin.
Meanwhile, leptin is produced in the fat cells, so the more body fat you have, the higher your leptin levels will be. Conversely, the thinner you are, the less leptin you’ll have floating around.
This is supposed to work as a way to regulate and maintain a healthy body weight. If you have lots of leptin in your system because you’re overweight or obese, it should work to ward off hunger and use up existing energy stores, leading to weight loss.
Meanwhile, when your energy intake is too low, like in a state of fasting, leptin levels plunge, stimulating appetite and increasing food intake.
When it works the way it’s supposed to, leptin can be pretty effective in weight management and controlling hunger vs appetite.
A 2012 study by Schulz et. al, for example, administered intranasal leptin to rats with diet-induced obesity and measured energy intake and body weight. Over the four-week period, they found that leptin was able to significantly suppress appetite and induce weight loss.
Hunger vs Appetite: Why does our brain sometimes feel hungry when our stomach isn’t?
Let’s be honest—it would just be way too simple if we had a built-in mechanism that controlled our hunger vs appetite and helped us keep our body weight in check.
Instead, overfeeding and obesity can blunt the effects of leptin in the central nervous system in a condition known as “leptin resistance.” So even though you have lots of leptin that’s supposed to be telling the brain to decrease intake, your brain just doesn’t get the message.
This can be seriously detrimental when it comes to your weight and might even be the reason you can sometimes “feel hungry”…even though you’re actually not.
If you’ve ever found yourself finishing off your second sleeve of Oreos without even batting an eye, leptin could be a possible culprit.
According to a review on leptin signaling published in the journal Annals of the New York Academy of Sciences:
Reduction of the leptin signal induces several neuroendocrine responses that tend to limit weight loss, such as hunger, food-seeking behavior, and suppression of plasma thyroid hormone levels.
Constant food cravings, carrying excess weight, chronic stress, difficulty differentiating between hunger vs appetite, and sleep deprivation are just a few possible symptoms that could signify leptin resistance.
But just because you feel hungry when you spot something savory doesn’t mean you’re leptin resistant.
External stimuli can also have a serious impact on appetite levels by triggering an increase in ghrelin. Studies have even found that seeing pictures of food can increase levels of ghrelin, which causes an increase in appetite, even if we’re not feeling physically hungry.
Does losing weight make you feel more hungry?
Because leptin is produced in the adipose tissue, losing body fat means a decrease in leptin. That sounds like it would be bad but it can actually be good, considering that leptin resistance tends to occur when we have way too much leptin floating around.
This has been demonstrated in several studies, including a study by Wing et. al that looked at the relationship between weight loss and changes in levels of serum leptin. Following a 4 month weight loss program, they found that leptin concentrations of participants decreased from 30.1 to 20.4 ng/ml.
One potential factor that could influence leptin resistance is hyperinsulinemia, or elevated levels of insulin.
The idea is that when we have high amounts of insulin, a hormone that’s responsible for transporting glucose out of the bloodstream, it can block the signal of leptin, leading to leptin resistance.
Preventing hyperinsulinemia by keeping blood sugar levels steady through a healthy diet could (possibly) stop this mechanism altogether.
This theory was studied by Lustig et. al in which 17 participants underwent a weight loss therapy using an insulin-suppressive agent, which was able to enhance sensitivity to leptin.
Insulin resistance, which causes chronically high levels of insulin, is one component of metabolic syndrome and can eventually lead to diabetes.
In addition to leptin, other factors can also influence our hunger levels–especially when we start cutting calories. In fact, many of us are probably familiar with the sudden surge in cravings we often get right after we start on a new diet.
The reason you might feel ravenous when you start eating less and losing weight? It could be due to your levels of ghrelin, which often increase as a compensatory change that accompanies weight loss.
Long story short: there are a lot of different factors that could potentially have a role in your levels of hunger hormones, but maintaining a healthy diet and healthy weight can keep it all under control.
How can you differentiate between brain hunger and stomach hunger?
Still, being able to differentiate between appetite (brain hunger) and hunger (stomach hunger) remains a problem for many of us. A few simple ways to tell if you’re actually feeling genuine hunger:
- Look for some of the physiological signs of hunger. If your stomach is growling or you experience hunger pangs, it’s real hunger and it’s time to eat.
- Determine what will satisfy your hunger. When you’re experiencing real hunger, any food will work. If it’s “brain hunger,” chances are you’ll find yourself craving something specific instead.
- Drink some water and wait. Sometimes hunger gets confused with thirst. If you drink some water, wait 10 minutes, and still feel hungry, it’s genuine hunger.
- Consider the timing. If your hunger came on suddenly, it’s probably nothing more than “brain hunger” and just a craving. If it has built up gradually over time, it’s more likely to be real hunger that you’re experiencing. This isn’t 100% accurate–think about if you’ve ever been super busy and forgotten to eat all day until you realized you were starving–but it is something to consider when looking at hunger vs appetite.
Other than hormones, what factors play a role in hunger vs appetite?
Besides your hormones, it seems that pretty much everything can play a role in your hunger levels.
How does the weather affect your hunger?
Interestingly enough, you’re more likely to feel hungry when you’re in cold weather than in hot weather. This is because calories equate to warmth and food moves faster through the stomach when you’re cold.
How does exercise affect hunger levels?
Regular exercise can actually reduce hunger levels. Exercise slows the passage of food through the digestive tract, meaning you’ll feel fuller for longer. One study by Sim et. al even noted that high-intensity intermittent exercise can decrease levels of ghrelin, helping to suppress appetite.
Does the thyroid play a role in appetite?
Additionally, changes in thyroid function can drastically affect hunger levels. Thyroid hormone plays a role in controlling everything from metabolism to muscle strength to appetite.
It is directly connected to the hypothalamus and can regulate appetite and food intake. Increased hunger can be a sign of an underactive thyroid gland and changes in appetite can also be a symptom of hyperthyroidism.
Do your eating habits and schedule have an impact on hunger?
Most of us have basically conditioned our body to eat at the same time everyday, so you might start feeling hungry as 6:00 rolls around, regardless of whether or not you’re actually hungry.
Research published in The Proceedings of the Nutrition Society has shown that establishing set meal times can actually be beneficial, though, citing irregular meal times as a risk factor for increased blood pressure, BMI, and LDL cholesterol.
How does your mood affect hunger?
Finally, let’s not forget how your appetite can drastically change during times of stress or depression.
After a rough break-up, for example, it can go one of two ways when it comes to hunger vs appetite. You might go several days without even thinking about food…or you might find yourself elbow-deep in a pint of ice cream.
Feeling depressed can affect people in different ways.
Lack of motivation, inability to experience pleasure, and loss of appetite are all common symptoms of depression, which could explain why nothing sounds appetizing at all when you’re super stressed or depressed.
On the other hand, depletion of serotonin can cause an increase in intake with animal studies pinpointing a specific receptor through which serotonin influences appetite and body weight.
Plus, as mentioned previously, everything from medications to physical conditions can affect your appetite and, thus, your weight.
How can you make friends with your appetite?
Though there are clearly many factors that have a role in our hunger and appetite, there are things we can do to keep it in check.
- Regular exercise can decrease appetite, plus allows you to take advantage of other exercise benefits, including weight control.
- Staying hydrated can regulate hunger and ward off cravings. Since dehydration can often be confused with hunger, keeping that water bottle full is super important.
- Start listening to your body to differentiate between “brain hunger” and actual hunger. Practice eating only when you’re actually hungry and you’re likely to see some changes in your appetite.
- Eat smaller meals throughout the day. Instead of just having three big meals, try splitting it up into smaller, more frequent meals. This can prevent cravings between meals and keep you feeling satisfied all day long.
- Finally, make smarter food choices. Even though many of us (myself included) like the idea of indulging in a big, sugary slice of cake for breakfast, it will do literally nothing in terms of satiety. Filling up on fiber and protein are both great options because they move slowly through the digestive tract, meaning you’ll stay fuller for longer.
- Additionally, picking high satiety foods, such as boiled potatoes, can decrease hunger. A validated satiety index was developed in 1995 by Holt et. al that evaluated the satiating capacity of common foods. Satiety, which is “the quality or state of being fed or gratified to or beyond capacity,” can help decrease feelings of hunger.
Below is the satiety index developed by Holt et. al. It shows how satisfying each food is compared to white bread, ranked at 100.
|Snacks and Confectionary
|Mars candy bar
|Breakfast Cereals with Milk
Clearly, hunger and appetite are complex topics that are controlled by many factors. In fact, researchers are still working to piece together how it all works in the body, especially in conditions like obesity. It still remains to be seen how these intricate issues will play a role in the future of weight management and health in general.
What are your thoughts on hunger vs appetite? Do you have any issues differentiating between the two or do you have any tricks to keeping a healthy appetite? Share in the comments!
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