Updated 10/8/23; Originally posted 7/27/22

Hunger is your body’s way of keeping your energy levels high by making you want to eat. Historically, this has been a life saver in the very real cave-woman sense. In today’s world where food choices abound, you are likely to find that your hunger signals make you eat more energy than you need because it is readily available. This post shares the science behind your hunger and offers a myriad of ways for you to satisfy yours with the goal of optimal health and feeling better not older!

Your brain, microbiome, and body decide together whether eating is a good idea. Many signals and much decision making goes into whether (and what) you eat. Understanding which type of hunger you are experiencing helps you decide what to do about it. Hunger is not always satisfied by the same course of action. If you want to read more, hop down to my Additional Reading resources.


Ghrelin Says Give Me Energy!

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If your body is in need of energy, the hormone ghrelin will rise until you begin eating. Ghrelin tells your brain’s hypothalamus that you are low on energy and your brain ramps up your appetite and your thyroid hormones (which help get the energy into the cells).

Not surprisingly, the best way to remedy this type of hunger is to actually eat. But eat what? Enough food as a whole to feel full physically. Enough fiber to feed your microbiome. Enough protein to keep you feeling full for hours after you eat. Enough carbohydrates and fats to provide fuel for your cells. But like goldilocks, you want to eat “just right” for you. Too little and you will be constantly eating (which is stressful to your body). Too much and you have excess energy to store in fat and a lot of inflammatory waste products to detox from your body.


Mood and a Reward Hungry Brain

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Sometimes the reward center of your brain needs a “hit” of something – some stimulation – in order to boost your mood. You are seeking an increased level of dopamine and serotonin. While there are a lot of healthy ways to activate rewards for your brain, many people head to food – called emotional eating – and their waist lines prove it. Serotonin is created in the gut so it makes sense that eating would do the trick!

Eating for the brain reward does not usually lead to food choices that support longevity and disease prevention unless you make a purposeful shift in that direction. That candy bar makes you feel great right now and in a few hours not so much. In a few decades, you might be staring at a diabetes or cancer diagnosis which could have been prevented if you had known more when you were younger.


Hunger Cravings and Your Thoughts

When you crave a particular food, do you think about it often? Visualize where and how you could be eating it? Remember that last time you had it? Do you create a picture in your mind of a plate or bowl full of that food? Wow, your brain is really ramping up your hunger!

The question is why? Are you truly in desperate need of some particular nutrient? Perhaps and for some this is absolutely true. A more common reason for cravings is that you have become metabolically inflexible so when your favorite fuel is used up (glucose or sugar) you don’t know how to use fats (ketones) as fuel for your body and brain.

The solution for cravings is multi faceted:

  • Make dietary adjustments to what you eat (less sugar, more healthy fats and proteins)
  • Change when you eat (daylight hours only which is a form of intermittent fasting)
  • Shift your thoughts away from food and towards something helpful via guided meditation


Leptin Says “Not Hungry” – Or Does It?

Your fat cells know that they exist and that they store energy. They tell your body that all the time via the hormone leptin. Leptin signals the body that there is no need to eat because you have enough “fat on the land” to fuel yourself. Leptin is not constant of course – it falls gradually after you eat and rises when you eat. When leptin lowers, your metabolism slows so you hold onto your stored energy in the form of fat.

People who have a good amount of body fat and high leptin might think – woohoo – I can skip this meal and free up time to to what is important to me! Low leptin levels for those with low body fat will instead be thinking – damn! – I need to eat again which takes up precious minutes every day. And as a bonus – you can be resistant to leptin which means your body ignores the leptin and you eat more food and more often than you really need.


Hunger from Poor Quality Sleep

Sleep plays in important role in your overall wellness including your hunger. When you have poor sleep, you are likely to be hungrier than normal the next day and crave higher calorie/higher carbohydrate foods. Poor sleep can be less total sleep hours than normal or it could be low quality sleep (interrupted, short amount of deep sleep, short amount of REM sleep??).

A single night of “poor” sleep will disturb the delicate hormone regulation of your appetite the next day – your leptin will fall and your ghrelin will rise – and you will want to eat! A single night of low quality sleep affects parts of your brain involved with higher order decision making and appetite – you will want reward foods. When you wake feeling unrested, you require more cortisol to function well and that makes you hungry too! Chronic inadequate sleep really messes with you – making you hungrier than you should be.


Intestinal Messages Stop Hunger

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Cholecystokinin (CCK) is a hormone produced by your intestines that says you are full! It takes protein and fat to stimulate this hormone as the food leaves your stomach and moves into the small intestine. It makes sense to me that if you eat too quickly, you do not give your body a chance to generate this signal to tell you when to stop eating. CCK also contributes to the feelings of fullness in the stomach that come from what you eat (protein and fat) rather than the volume of what you eat.

If you lose weight too quickly, your CCK levels fall so you feel less full after a meal – encouraging you to overeat and get back in balance! Interestingly, CCK can also be produced in the brain and is associated with anxiety, panic disorders, and the eating disorder anorexia nervosa. The gut and brain connection strikes again!


Does Exercise Make You Hungry?

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Exercise is absolutely a beneficial stress to your body and is highly correlated with weight management efforts. Longer duration low-medium intensity exercise is associated with being ravenous afterwards. You use up energy and your body is eager to replenish your energy stores in your blood, muscles, and liver.

Short term high intensity exercise has been known to lower hunger signals because the high intensity exercise is so stressful to the body that it wants to focus on repair first and replenish second. How do you know what activities do each for you own unique body? Experiment!


Does Stress Make You Hungry?

Some people are stress eaters – some are stress fasters. Which one are you?

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When you are under stress, your adrenal glands make more stress hormones like cortisol. Making cortisol takes away resources that could be used to make your other regulatory hormones and affects your blood sugar regulation. A rise in cortisol also lowers your appetite temporarily in case you have to fight or flee. Stress affects the brain as well – increasing the chance that you will want to eat for pleasure to offset the stress.

Extended elevated cortisol will result in an extra layer of belly fat and loss of muscle tissue. The question of whether stress makes you hungry or not might be less important than understanding that stress is hurting your body and mind in multiple ways!


Your Microbiome Needs to Eat Too!

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Not all of your hunger signals come from your own cells. You can also receive chemical messages from your microbiome. The beasties that live in your gut want food and they require you to give it to them. Candida bacteria love sugar. Is that desire for a sweet treat for you or a request from your candida friends? Do you want to feed them and help them proliferate?

Your beneficial bacteria colony inside your gut needs to be fed in order to do the work to extract nutrients from food for you to use. Bacteria food is fiber. Guess what foods contain fiber? You got it – vegetables and fruit. Not enough fiber means you have a hungry cranky microbiome that does not digest food well. No nutrients for you! Too much fiber leads to a microbiome that is swimming in so much potential food that they can not get any work done but your cells are unsatisfied. To add complication, there are several types of fiber – but all that is for another post! Keep in mind that part of your hunger is about feeding your microbiome for your own personal optimal wellness.


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Additional Reading