The Brain Controls Hunger: A Brief Overview
There are two types of food intake – non-nutritive (food) and nutritionally (energy). Food intake is controlled by the brain. There are three major areas where food intake takes place:
1. Central Nervous System (CNS): The CNS consists of the brain stem, spinal cord, thalamus and cerebellum.
It includes the hypothalamus, pituitary gland, stomach and intestines.
2. Subcortical Nervous System (SNS): The SNS consists of the amygdala, hippocampus and striatum.
3. Hind-brain: The hind-brain consists of the pons and medulla oblongata.
It controls the heart rate, breathing and digestion.
What part of the brain controls hunger?
The hypothalamus is the part of your brain that controls hunger. The hypothalamus has a direct effect on hunger and satiety. Some parts of the brain affect hunger indirectly. These parts of the brain can be found in the central nervous system and the hind-brain. The hypothalamus is part of the diencephalon. The diencephalon consists of three parts:
The hypothalamus consists of several specific nuclei. These nuclei include the:
1. Lateral Hypothalamic Nucleus (LHN)
2. Ventromedial hypothalamic nucleus (VMH)
3. Suprachiasmatic Nucleus (SCN)
4. Paraventricular Nucleus (PVN)
5. Median Preoptic Nucleus (MPO)
6. Dorsomedial Hypothalamic Nucleus (DMH).
What part of the brain is responsible for controlling hunger?
The hypothalamus has a close, direct connection to the brain, heart, lungs and digestive tract.
The hypothalamus and satiety: Satiety is the feeling that leads you to stop eating after a large meal. After eating a full meal the stomach begins to send messages to the brain. These messages are sent through the nerves that connect to the stomach. The hypothalamus also receives these signals. Once this happens the hypothalamus tells the pituitary gland to stop sending out the hunger hormones.
This stops the feeling of hunger.
The hypothalamus and hunger: Not everyone who is hungry actually feels hungry. Many people eat without even feeling hungry. If you are hungry then this is the signal for your brain to stop eating. The hypothalamus is part of a system that helps control hunger and fullness. The hypothalamus is also connected to the following:
1. The pituitary gland
2. The stomach
3. The small intestines.
4. The pancreas
5. The liver
6. The kidneys.
The hypothalamus consists of several parts that control hunger and fullness. These parts include the following:
The medial pre-optic area (MPOA). This part of the hypothalamus is linked to feelings of sexual desire and hunger. It plays a role in eating behaviour.
The lateral hypothalamus (LH). This part of the brain is related to reward. It also controls several instincts and basic behaviours. It is also linked to feelings of anger, aggression and fear. These feelings can lead to eating because people seek comfort in food.
The ventromedial hypothalamus (VMH). This part of the brain plays a role in controlling eating habits. It also controls body temperature and maternal behaviours. When this part of the brain is damaged, animals eat prey despite the fact that they are full. This part is also linked to feelings of anxiety.
The paraventricular nucleus (PVN). This part of the brain controls the release of posterior pituitary hormones. It is also linked to the thyroid gland, adrenal cortex and gonads.
The arcuate nucleus (ARC). This part of the brain secretes hormones that control hunger, fullness and energy levels. It is linked to the stomach and small intestines.
The lateral hypothalamic area (LHA). This part of the brain affects sexual behaviour and feeding patterns. It is linked to the stomach, pancreas, lungs and intestines. It also controls body temperature.
The dorsomedial nucleus (DMH). This part of the brain is linked to maternal behaviours, aggression and dominance. If it is damaged then animals stop caring for their young.
The ventral tegmental area (VTA). This part of the brain plays a role in reward. It is also linked to feelings of pleasure.
The brain influences how food tastes. It does this by affecting how your taste buds react to food. It can also influence how the digestive system works. Your brain can also change how it reacts to different tastes. This helps you to better enjoy good tasting food.
If the taste buds on your tongue are damaged then you lose your sense of taste. You may still be able to eat, but food won’t taste good.
The areas of the brain that are linked to food and eating are:
1. The amygdale.
This is an area that forms part of the cerebral cortex. It plays a role in emotional responses. It also plays a role in behavioural responses to things that are linked to emotions. When someone tastes something bad, this part of the brain tells them that it is bad. It also tells them to avoid it in the future.
2. The frontal lobe.
This area is linked to personality and behaviour. It is also linked to learning. If someone tastes something bad, then the memory of this bad taste can be stored here. This part of the brain works with the hippocampus. This is the area of the brain that forms memories.
3. The insular cortex.
This part of the brain monitors internal body states. It then lets you know how you should feel emotionally in relation to these states. For example, if you taste something really sweet then a message will be sent to this area of the brain. The brain will then tell you if the taste is good or bad. The message is then passed on to the amygdale so that you can experience the associated emotion at the same time.
4. The parietal lobe.
This part of the brain monitors the sense of touch. It lets you know where different parts of your body are in relation to the environment. The frontal lobe, parietal lobe and insular cortex work closely together. This allows you to experience taste fully.
If you have a normal brain then your sense of taste should be fairly accurate. However, if you have a disease or condition such as Parkinson’s Disease, you may not experience taste properly.
Storage and Appetite
The hypothalamus is the part of the brain that controls your appetite. It also controls other metabolic functions. It does this by releasing a variety of different hormones into the body. These include:
This hormone is released from fat cells. It controls how hungry you are.
This hormone is produced in the stomach. It makes you feel hungry.
This hormone is released when you eat. It slows the rate at which your stomach muscles contract. This leads to a feeling of fullness.
This hormone is released into the small intestine. It slows the rate at which nutrients are absorbed into the bloodstream. It also makes you feel full.
This hormone is released after you eat carbohydrates. It lowers your blood sugar levels. This makes you feel less hungry.
The hypothalamus is also linked to the area of the brain that controls emotion and behaviour. This helps you to link your emotions to eating. For example, you may enjoy eating a tasty meal and feel elated as a result. You may then associate feeling elated with eating the particular food that made you feel that way. When you feel miserable, you may eat the same food and this makes you feel a little happier.
This then reinforces your eating habits and you continue to eat this food when you are miserable.
You are also likely to link emotions to food because when you taste certain foods they bring back memories of events or places. You may associate a certain food with a happy occasion. You may then feel happy when you eat that food as your brain has made the link. The reverse is also true. You may eat a food and feel sad because it reminds you of an unhappy event.
5. The Importance of Sleep
Most people spend one third of their lives asleep. It is an important process that forms an essential part of our lives. We not only spend a third of our lives doing it, sleep is also necessary for our well-being.
Most people sleep nightly. It is necessary for our minds and bodies to get rest. Sleep also allows us time to think without being distracted by our surroundings. This is why we sleep at night and sleep during the day as our surroundings are different.
There are 5 stages of sleep. Each stage has a different function.
1. If you are asleep and a loud noise is heard, you will instantly wake up.
This is because the brain has identified the noise as being important so awakens you immediately. This is known as sleep stage 1.
2. Sleep stage 2 is slightly deeper than sleep stage 1.
If another loud noise is heard, it will take longer to wake you up.
3. Sleep stage 3 is even deeper than sleep stage 2.
It is harder still to wake you up. If a loud noise is heard, you may not wake up at all.
4. Sleep stage 4 is known as deep sleep.
Breathing and heart rate are noticeably slower than in the other sleep stages. The brain produces very little brainwaves in this stage. Waking a person in deep sleep is very difficult and most people will not remember much if any of this sleep stage.
5. REM (Rapid Eye Movement) sleep is the final and shortest sleep stage.
The EEG will show brain activity similar to that when you are awake. Most of your dreams occur in this sleep stage.
Sleep deprivation has many negative effects on the body. These may include hallucinations, inability to learn, depression, irritability and weight gain. Sleep deprivation can also lead to death after a few days. The medical term for death by lack of sleep is called fatal familial insomnia.
If you are sleep deprived, your mind will try to make up for lost sleep. After a night of no sleep, you will feel very unfocused. However, a nap of less than 30 minutes will allow you to feel refreshed. This is because a sleep cycle of between 30 minutes and 1 hour is all that is needed to refresh the body.
A student should get between 8 and 10 hours sleep a night. This allows time for periods of REM sleep that is important for learning. REM sleep allows the brain to process and learn new information. If you are sleep deprived, your mind may find ways of pretending you are in REM sleep. This may cause vivid dreams that seem very real.
If you are not getting enough sleep your mind may start to wander. You will find it hard to stay focused on one train of thought. You may start daydreaming and find that your mind has wandered away from any subject you are studying or any conversation you are having.
It is possible to push yourself past the point of sleep deprivation. You may feel more awake than ever. This is a false sense of energy and will take it’s toll later. Your mind and body are not functioning properly and you may have accidents as a result.
Remember to get a good night sleep each night. A good sleeping routine will ensure you wake up refreshed and ready to learn. This routine should be started a few weeks before the exams. A bedtime around 10pm every night will allow for 8 hours sleep. Set this as a routine and make sure you stick to it, even during weekends.
This routine should also include your morning wake up time. Plan your day so you can wake up early and still get everything done that is needed. A morning routine is very important and should include things like eating breakfast, planning your day and of course, learning.
Sources & references used in this article:
- The brain, appetite, and obesity (HR Berthoud, C Morrison – Annu. Rev. Psychol., 2008 – annualreviews.org)
- Brain regulation of appetite and satiety (RS Ahima, DA Antwi – Endocrinology and metabolism clinics of North …, 2008 – Elsevier)
- Brain control of appetite during sickness (G Aviello, C Cristiano, SM Luckman… – British Journal of …, 2020 – Wiley Online Library)
- Appetite and body weight regulation: is it all in the brain? (SP Kalra – Neuron, 1997 – cell.com)
- Appetite control and energy balance regulation in the modern world: reward-driven brain overrides repletion signals (H Zheng, NR Lenard, AC Shin… – International journal of …, 2009 – nature.com)
- Brain regulation of food intake and appetite: molecules and networks (C Broberger – Journal of internal medicine, 2005 – Wiley Online Library)
- Brain mechanisms underlying flavour and appetite (ET Rolls – … Transactions of the Royal Society B: Biological …, 2006 – royalsocietypublishing.org)
- Microbiota-gut-brain axis: modulator of host metabolism and appetite (M van de Wouw, H Schellekens, TG Dinan… – The Journal of …, 2017 – academic.oup.com)