When it comes to achieving optimal body composition, getting your appetite under control is a deal breaker. What a lot of people don’t realize is that sensations of hunger are tightly controlled by hormones and neurotransmitters in the body.
These chemical messengers are not only influenced by energy availability, but also by reward-driven factors and stress. This means that your environment plays a primary role in how much you eat. For example, simply having a meal with a group of overweight friends will increase how much you eat.
This article will help you understand how hormones influence hunger. With this critical information, you won’t need an expensive pill or a deprivation diet to lose body fat. Instead, you can create a lifestyle that helps you control hunger and achieve optimal body composition once and for all.
How Food Intake Is Regulated
Ever wonder why some days you feel like you could eat the entire refrigerator whereas others you’re not hungry at all?
Is it your stomach size? Stress? The weather?
It all starts with your stomach: When empty, your stomach experiences contractions, which remind you to eat. Then, the hormone ghrelin is released from the GI tract.
Ghrelin has a two-fold effect on increasing food intake by directly stimulating appetite and causing the release of brain transmitters that amplify the hunger effect. Ghrelin also acts on the limbic system, which is the reward center of the brain. This is important because in addition to the physical hunger you experience, which ensures the body and brain have the energy necessary to keep you alive, you also experience a psychological-driven emotional hunger.
In science, this is known as the hedonistic drive to eat. It is a pleasure, reward-associated mechanism that underlies the desire to eat mainly high-carb, high-fat foods despite sufficient calorie intake. At first glance, you might think that your hedonistic drive is the only problem when it comes to fat loss and hunger.
Unfortunately, the separate hedonistic and homeostatic systems are interrelated and can easily get out of whack, especially when you cut calories, over-exercise, or eat an unhealthy diet.
For example, ghrelin goes up when your stomach is empty to remind you to eat (homeostatic system) but it also interacts with the brain and gives you “food memories,” which motivate you to seek out more pleasurable high-fat, high-carb foods (hedonistic system).
Curiously, there is evidence that obese people may have fewer receptors in the limbic system, which lead them to eat more in an unconscious effort to stimulate those receptors and feel good.
Insulin & Leptin
Two other powerful but often misunderstood hunger hormones are leptin and insulin. These babies are very interesting:
Insulin can have either a hunger-stimulating effect or an appetite-suppressing effect, depending on the environment that it’s in. When insulin is elevated in response to an increase in blood sugar, it will decrease hunger and slow eating.
However, if insulin is high and blood sugar is low (a physiological environment that really is not supposed to occur), insulin will ramp up hunger sky high. This is the problem we’re seeing with diabetes and diets high in refined carbs.
When you eat foods high in refined carbs, which are quickly digested, blood sugar is rapidly elevated. The pancreas responds by releasing insulin, often secreting too much to compensate for the high blood sugar.
Insulin stores blood sugar as either glycogen in the muscle or as fat. This happens very rapidly, leading blood sugar to plummet, but there’s still a bunch of insulin left in the blood due to its oversecretion. The combination of elevated insulin and low blood sugar causes continued sensations of hunger and intense cravings for carbs even though you just ate!
On the other hand, when you are insulin resistant, as in the case of diabetics, insulin levels stay elevated all the time, leading to increased appetite and triggering food intake.
Then there’s the hormone leptin, which is secreted from fat tissue once insulin begins to drop to fasting levels. It travels to the brain and binds with receptors to reduce hunger and increase metabolism. Leptin triggers a cascade of appetite suppressing hormones and is very important for overall hormone balance.
However, it’s possible for the brain to become resistant to leptin’s message to reduce hunger. This is most common in people who eat the majority of their calories at night, binge eat, eat long-term low-carb diets, or have a habit of dieting.
Part of the reason problems with leptin and insulin are so common and profound is that these hormones are involved in a tightly controlled cascade of chemical messengers and when one is out of balance, all of them will be.
What follows is a description of the different chemicals involved in the hormonal cascade that turn hunger “on:”
#1: Neuropeptide Y (NPY) stimulates eating and promotes fat storage while also increasing the number of fat cells in the body. Stress and high levels of cortisol raise NPY so that you crave high carb, high-calorie foods.
#2: Orexins cause havoc on your metabolism because they downregulate activity (making you feel lazy) and stimulate eating even though you’re satiated. They are triggered by high-carb foods.
#3: Galanin increases when drinking alcohol and fatty foods, giving you a voracious appetite even when you should be full.
#4: Dynorphin is a pain-reducing, morphine-like substance that stimulates the intake of highly palatable foods containing fat and sugar. It’s a key transmitter implicated in stress eating.
#5: Norepinephrine increases meal size and carb intake, but it’s not all bad, because this hormone also triggers thermogenesis or energy expenditure so that you burn more calories.
#6: Agouti and MCH trigger appetite and fat overconsumption.
All of these chemical messengers increase in response to a calorie imbalance (dieting, calorie restriction, excess exercise) and many are triggered by stress. This is an evolutionary adaptation because food was often scarce in “stressful” times, and release of these hormones would motivate us to search for food.
Fortunately, there are also chemical messengers that have the opposite effect and turn hunger “off:”
#1: POMC and MSH are stimulated by leptin, reducing hunger and lowering drive to eat.
#2: CCK, and Peptide YY are all released from the GI tract in response to protein foods, decreasing hunger and suppressing appetite.
#3: Serotonin is a “feel good” neurotransmitter that promotes fullness and satisfaction. It opposes norepinephrine and decreases rate and duration of eating so that you consume fewer calories.
#4: Glucagon is secreted by the pancreas to trigger short-term feelings of fullness. It is best known as an insulin antagonist because it rises when insulin is reduced and enables fat burning instead of storage.
Now that you’ve got a handle on your hunger hormones, some tricks for creating the right metabolic environment to minimize hunger and raise metabolism are in order:
Tip #1: Improve insulin sensitivity with a higher protein, lower carb diet that is based around whole foods: Fish, meat, eggs, vegetables, fruit, nuts, seeds, and other healthy foods.
Tip #2: Low-carb doesn’t mean no-carb. Be sure to include some complex carbs in your diet (either daily or in a cyclical fashion) to signal the hypothalamus to hit the leptin reset button so you support the metabolic hormone cascade.
Tip #3: Avoid simple and refined carbs, which wreak havoc on blood sugar and insulin and stimulate hunger.
Tip #4: Avoid processed foods that are engineered to light up reward centers in the brain and trigger your hedonistic hunger response.
Tip #5: Pair foods that increase insulin sensitivity with higher carb foods: Cooking with olive oil, vinegar, spices, and lemon will all improve insulin health and enhance flavor for more delicious meals.
Tip #6: Choose a meal frequency and stick with it. Whether eating 2, 3, or 6 times a day works for you, create structure to your eating: Eliminate random snacking, stop skipping meals, and avoid making unhealthy choices when you’re famished.
Tip #7: Cope with your stress. Promoting a balanced cortisol curve is key for avoiding cravings and emotionally-driven hunger.
Tip #8: Eat higher protein meals during the day, saving your higher carb foods for night.
Tip #9: Use the Japanese approach to eating called Hara Hachi Bu, which tells you to only eat until you are 80 percent full.
Tip #10: Don’t forget to exercise! Working out with weights or doing intervals can improve insulin sensitivity and fight stress, while raising POMC for an appetite suppressing effect.