What is hunger?
It’s our most primal instinct and something we experience multiple times a day. But what is hunger, exactly?
Hunger causes you to seek energy (calories) that your body needs to move, breathe, and perform hundreds of other vital functions. Sometimes it may cause your stomach to rumble or create other sensations that alert you that it’s time to eat.
In modern-day society, it’s common to become hungry about 4 to 5 hours after eating a meal. However, it might happen as soon as a couple of hours or more than 12 hours afterwards.
Factors that affect how hungry you become after eating — and how soon it happens — include:
How many calories you ate1
The macronutrient mix (ratio of protein, carbs, and fat) of your meal2
Your body’s metabolic response3
Is it hunger or appetite?
There’s a subtle difference between hunger and appetite. Appetite is a desire to eat, which is often increased by seeing or smelling delicious foods. By contrast, hunger tells your body that it needs food now, from any source that can provide it with energy.
When your stomach is empty, it triggers cells in your digestive tract to release ghrelin. Known as the “hunger hormone,” ghrelin signals your brain to rev up production of stomach acid, priming your body to receive and digest food. Once you’ve eaten, the ghrelin-releasing cells receive a message from your full stomach to stop producing ghrelin, and you no longer feel hungry.4
Unfortunately, this system doesn’t always function the way it should. The most extreme example of this is Prader-Willi syndrome. Children with this condition are obese, yet driven to eat constantly due to chronically elevated levels of ghrelin, which keep them hungry.5
Ghrelin and opposing “fullness” hormones like GLP-1, PYY and CCK may have played important roles in our evolutionary past. Hunger prompted our hunter-gatherer ancestors to seek food for fuel and nourishment. And since eating is necessary for survival, we seem to have evolved to find it pleasurable as well. So hunger and appetite are intrinsically linked.
There are different levels of hunger, of course. When you haven’t eaten for several hours, you might have a few vague, mildly uncomfortable hunger pangs. If you don’t eat right away because you’re focused on work or another project, hunger may go away temporarily.
On the other hand, going without food for a long time may cause a painful, gnawing feeling in your stomach, along with headaches, dizziness, or other symptoms. Still, certain individuals seem to be able to go much longer than others without getting hungry.6
Other reasons you may want to eat
Being hungry isn’t the only thing that makes us want to eat, though. When trying to lose weight, confirming that what you’re feeling is truly hunger before you start eating is key.
There are a number of things that can seem like hunger, but aren’t.
Eating due to stress: Feeling anxious and in need of a “nervous nibble”? We all tend to eat in response to stress from time to time. However, snacking to calm nerves seems to be especially common in people who struggle with their weight.7
Eating to relieve sadness or loneliness: Similarly, when you’re sad or lonely, you may reach for food to relieve these feelings. This is sometimes called “comfort eating” or “emotional eating.” If you’re an emotional eater, the drive to consume food can be so strong that it may feel like true hunger.8
Eating out of boredom: Feeling bored might prompt you to head to the kitchen and peek in the refrigerator or pantry for inspiration. Although this may momentarily distract you from boredom, it can lead to eating when you aren’t actually hungry.9
Eating out of habit: Sometimes it’s hard to tell if you’re eating according to your routine or in response to genuine hunger. Humans are typically creatures of habit. You may get used to eating certain foods at specific times without actually considering your hunger and appetite.10
Eating in response to external cues: Finally, the appearance of food may lead you to mistake a desire to eat for hunger. Walking past a restaurant with tantalizing sights and aromas, seeing a table of mouth-watering appetizers at a party, and other external cues may persuade you to eat because you start thinking you’re hungry — even if you’ve recently eaten.11
What to eat to lower hunger
Intentionally restricting calories to lose weight tends to be counterproductive because it often leads to feelings of hunger and deprivation. This may be one of the main reasons low-calorie diets typically fail to produce lasting weight loss.12
Fortunately, there’s a much more sustainable, pleasurable, appetite-suppressing way to lose weight. Enter a low-carb lifestyle.
Keep carbs very low
One of the first things you’ll likely notice soon after cutting carbs is that you’re just not very hungry anymore. This may be partly due to having higher blood levels of ketones, the fat-like compounds made in your liver. When carb intake is very low, your liver ramps up ketone production, creating a state of maximum fat burning called ketosis.
Research has repeatedly confirmed that being in ketosis can be a powerful appetite suppressant during and after weight loss.13
In fact, several studies have shown that when people dramatically cut back on carbs but are allowed as much protein and fat as they want, they end up automatically eating less because they’re no longer as hungry.14 Although the precise mechanism isn’t entirely understood, higher ketone levels are linked to a reduction in ghrelin (the “hunger hormone” discussed earlier) and an increase in “fullness” hormones like GLP-1 and CCK.15
By Franziska Spritzler, RD, CDE (The Diet Doctor)