A scientist names Jeremy England has come out with a theory which potentially proves that life can exist without god and that god did not create us. Jeremy England’s theory has been developed on Charles Darwin’s idea of evolution. He says that the idea not only applies to things which are alive but to the creation as well. Meaning that evolution not only takes place while we are alive but at our creation as well.
The scientist says that it is thermodynamics that plays the major part in our creation and not a ‘creator’ who is at work. The theory of thermodynamics says if you start with a random clump of atoms, and if you shine light on it for long enough, it should not be surprising that you get a plant. If these atoms are exposed to an energy source (i.e. the sun), these are bound to grow and restructure themselves which eventually leads to life.
The theory was posted on Richard Dawkins website, a famous Athiest scientist, and is titled ‘God is on the ropes: The brilliant new science that has creationists and the Christian right terrified’. The blog post was written by Paul Rosenberg, and it looks as though this theory has got the scientific community quite excited.
Charles Darwin’s theory focused more on life progression but the blog post by Paul Rosenberg has got everyone excited about the Jeremy England’s development on Darwin’s idea.
The theory by Jeremy England has been developed on mathematical facts which questions the existence of god and forces us to think about it in a deeper sense.
Author: Aksheev Puri
If you have started making more typing mistakes, aren’t able to think as fast and as creatively as you could a few years ago, indications are clear that you losing grey cells.
It’s no secret that we lead stressful lives. The pressures of scoring well, bagging a great job, and an amazing life partner takes a toll on the best of us. Usually, the first thing to be compromised is health. We try to undo the harm by frequenting the gym. But little do we realize that the most affected organ in the long run is the brain.
Here are 10 daily habits we follow that are causing us brain damage and gradually making us dumber. Stop practising these right away!
1. Using Your Brain During Sickness
Not for nothing do doctors advise rest when you are sick, and even if you are feeling fine. The brain works overtime during illness. If it’s an infection, the brain has to send signals to lymph nodes to fight the infection. Overworking your brain at this sensitive stage will only lead to destruction of some of your grey cells. During fever, the body temperature is already high and if the brain is forced to function, it will not only worsen your temperature, it can overheat the brain too. True case of bheja fry. So, when unwell, keep calm and take a nap.
2. Skipping Breakfast
While you might feel tempted to rush out in the mornings skipping breakfast, thinking you’ll have something later, the habit is extremely harmful in the long run. It deprives your brain of nutrients for a good part of the day and forces it to function on a malnourished state. Not eating in the morning lowers your blood sugar level, thereby depleting your brain of essential nutrients required to keep it healthy. In the long run, this will gradually slower you down.
The solution to skipping a meal is NOT overeating. In fact, overeating can also prove harmful for your brain. Eating more than what your body needs can confuse the brain and cause an imbalance in insulin production. Not only can it lead to obesity and diabetes, it can also cause hardening of arteries which leads to a decrease in mental function over the years. As they say, a fit body will house a fit mind.
So, our brain is mostly water, and when we decide to sit in the AC for too long and not drink enough water, the cells in our body begin to shrink. The body, in the absence of water, borrows water from the brain, causing the cells to shrink further. Nobody is too smart on a parched brain.
5. Too Much Sugar
Okay we know you love you gulab jamuns and pastries, but if you’ve got to remain sharp enough to impress the ladies, cut down on that sugar intake. Studies have shown that consistently high levels of blood sugar can prove harmful for your memory and learning capabilities. In other words, eating too much sugar can make you stupid.
6. Covering Your Head While Sleeping
No matter how cold it is, never cover your head while sleeping if you want your brain to be as fit as your flexing abs. When you pull the blanket over your head, you cut off fresh air and expose yourself to more of carbon dioxide. Now we all know what lack of oxygen to the brain can do to it. Studies have shown a daily habit of covering your head while sleeping can lead to chronic headaches, and even dementia!
We all know stress is not good for the body. But the biggest harm it does is to the brain. When we stressed out, our kidneys produce a chemical called cortisol which in turn can kill our brain cells if produced in excess. So basically, if you stress too much over that presentation tomorrow, chances are you might screw it up.
8. Lack Of Sleep
After years of staying awake late chatting online and watching movies, going to bed early is a tad too difficult. But all those night hours have done and are still wreaking too much havoc with our brains. Lack of sleep causes a
No use staying awake mugging chapters the night before exam; it’ll anyway slow down your poor brain.
This one is a no brainer. Smoking messes up with a lot of things in our body, one of them being the brain. It has been found (in a study at Mcgill University) that smoking causes thinning of the cortex over time. Long story short, smoking causes your memory and language skills to go haywire in the long run. Not a very attractive thing to happen, eh?
Now this one is no secret. Your mother must have often told you how your brain has rusted from underuse. Well, she is kinda quite right on this one. The brain is one organ in the body that develops with use. Just like our body needs exercise for the muscles to remain toned, the brain needs activity to remain sharp. Leading a dull sluggish life that does not require you to think on your feet can gradually make you dumber. So get out those crosswords and solve that sudoko! Psst, they say even memory-based online video games help!
P.S. – Brain damage here means subtle and gradual changes in the functioning of the brain that you might or might not notice. It doesn’t include a drastic failure in brain function. IT covers mostly cognitive abilities, memory and learning skills.
Photo: © Shutterstock (Main Image)
Author: Nishi Jain
Ever since Mark Zuckerberg changed his Facebook profile picture to a tricolor shade to show support to the Digital India campaign by the Modi government, we Indians have been following suit. Our timelines are flooded with tricolor profile pictures created from fb.com/supportdigitalindia. Now like everybody, you may think this is a gesture to support digital India. But it is not.
Changing Your Profile Picture Means You Have Automatically Voted Against Net Neutrality
For every profile picture that is changed, a vote goes in support of internet.org. Yes, it means you’ve automatically voted against net neutrality.
Now it may sound like a great philanthropic idea, one that would help digitalize even remote villages, it actually is a blow to internet freedom and net neutrality. Facebook is piggyback riding the digital India movement (which is a great ) to position itself as a benefactor that will provide free internet in India. Fact is that internet.org, if implemented, will do everything except benefit a developing country like India. Here’s why:
The free internet service will be available only to Reliance users, since the partnership is with Reliance. And the “free access” that is being much talked about will only be to Facebook and its 50 partner sites, which is nothing but manipulating internet users with a carrot-stick tactic. Everyone loves free internet, which is why users will limit their internet usage to sites that are free. Now this is giving unprecedented monoply to Facebook and its 50 partner sites to manipulate what we see on the internet.
Death Of Startups
And this will mean the death of startups, a culture that is booming in India. No small company or website can possibly compete with a biggie like Facebook that is providing free internet. The mushrooming of a zillion new businesses, especially indigenous, will simply be impossible. Imagine what would have happened if the British had priced English goods at dirt-cheap rates; yes, death of indigenous business. Clasicc case of big fish eliminating small fish.
Some time back, when the country had risen in support of net neutrality signing petitions to save it, big players like The Times of India and NDTV had pulled out of internet.org citing the violation of net neutrality.
So, if you think that by changing your profile picture you are supporting the cause of a digitalized India, don’t. You are unconsciously helping Facebook kill net neutrality. This Facebook post sums it all too well.
Photo: © Facebook (Main Image)
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A “successful life” will hold a different meaning for each of us. What makes it a success is determined by the goals, dreams, aspirations you have in your mind and heart. Having a successful life starts with beating your doubt, fear, and self-limiting beliefs, and getting honest about the kind of life you want to live.
Too often, we wait for permission to take action on the changes we would like to make in our life. For 12 years, I waited for all the stars to align before I took the first steps towards a better life. It took three years of doing things that I long believed were impossible to achieve what success means to me.
If we could define a successful life in one word, that word would be freedom. Each of us longs to live life by our design. We long for the freedom to live each day—and each moment—the way we want to live it. If you are going to achieve freedom in your life, if you’re going to find success, you’re going to have to develop the right habits.
Quick wins aren’t real change. Changing your habits leads to lasting success in your life.
Here are five habits, that if worked on daily, will lead you to whatever a successful life means to you:
1. Continuing to Learn
Brendan Burchard wisely said, “An expert is a student first.” While there are too many cases of information overload happening today, the right knowledge can significantly increase your progress in life. It’s time to immerse yourself in great books, podcasts, and videos that motivate you to chase bigger dreams.
We live in a time with unparalleled access. We have access to all the information we need to help every area of our life. Develop a habit of continuing to learn from the places that will help your next steps in your journey to a successful life.
2. Maintaining Your Health
Your health has a positive or negative effect on every area of your life. The way your mind and body feels can be directly traced to the things you eat. Your food choices will affect how you live and how you achieve success. Exercise is a great way to stay in shape, get more energy, and vent out any frustration. Maintaining your health will pay dividends and is a habit that leads to success.
3. Purging Negativity
Deciding to make big changes in your life is hard. The journey is compounded when you add negative people or habits. Negativity will convince you that your self-limiting beliefs are right. Negative people are struggling with different areas of their life and project their struggles onto you.
To experience success in your life, you have to stay away and be on guard against the effects negativity can have on you. Make it a habit to purge negativity and surround yourself with love and positivity.
4. Embracing Failure
The standard view of failure is typically negative—it doesn’t have to be. Failure can mean that the current way you tried something doesn’t work, and you just need to adjust your approach. Failure means that you are trying something—that you’re taking action. Too many people will stay stuck because they’re afraid to fail.
If you think about it, that can be one of life’s biggest failures. Embrace failure, if you are taking action towards a better and successful life. Make embracing failure a habit because it means you’re consistently taking the necessary steps towards success.
“Success is walking from failure to failure with no loss of enthusiasm.” – Winston Churchill
5. Choosing to Live Instead of Exist
Life can be a lot of the same old, same old. We get stuck in routines, and our lives almost become one giant checklist. As we live each year without making the changes or living the kind of life we want to live, we end up existing in life.
Truly living doesn’t mean traveling the world and jumping off of cliffs in some cool country—unless that’s your dream. It means that you don’t settle for a good enough life when you could be living your dream. Make it a habit to truly live each day as if it were your last because it might be.
“Are you truly living, or just breathing?” – Jensen Siaw
I didn’t get any lucky breaks. I didn’t win the lottery or get a big inheritance. I worked hard on creating these habits in my life and took focused action for three years. Today I wake living my dream life and what a successful life means to me. I wake up each day determined to keep building on the progress I’ve made.
You can do this. You can create healthy habits that lead to an incredible life. You can wake up each day happy, knowing you’re living the kind of life you’ve always dreamed of living. It will be hard. It will take time—maybe a lot of time. But, it will be worth it to spend each day living life on your terms. You’ve got this!
What habits are you working on that are leading you towards success?
Rejection is simply one of the most hurtful things that can happen to any person. What makes it even more painful is the fact that whether we like it or not, it is bound to happen.
More so, anyone can face rejection in any area of their life. Regardless of where it occurs, the effects of rejection are the same. It hurts, it’s no fun and it happens to be the number one reason people are afraid to try. When faced with rejection, it is super important to have the strength to face rejection head on, accept it, learn from it and simply keep on pushing on.
But of course, this is easier said than done. All things equal, the number one major weapon that one needs when containing and dealing with rejection is motivation. Mind you, it is a difficult weapon to master when dealing with rejection which coincidentally has a devastating effect on one’s personal motivation. However, if you are struggling with staying motivated in the face of dealing with rejection in business or life, take a look below.
Here are 4 ways to help you stay motivated and conquer rejection in its tracks:
1. Be coachable
You try, you get knocked down. You keep getting knocked down and can’t seem to figure out why? We have all heard it, it is probably one of the most popular definitions floating around today. What you ask? It’s the definition of insanity; doing the same thing over and over again and getting the same results. Every cloud has a silver lining and by being coachable, you open yourself up to the opportunity to learn new skills and improve the way you do things. There is no doubt about it, for learning and improvement to occur, one must be coachable. There is no short cut to this! Being coachable is about being open to the feedback and opinionsgiven by others and using that feedback to help improve yourself in all facets of life.
On your journey of defeating rejection in its tracks, do yourself a favor and don’t let arrogance, defensiveness, pride or ego hinder your ability to become better at what you do. These traits must be avoided at all costs. Instead, one must embrace humility, objectivity, approachability, confidence and receptiveness among other things. Most importantly, don’t be afraid to relinquish control to help you stay motivated in overcoming the rejections you’re facing!
2. Keep your eye on the prize
Yes, you have been rejected, that doesn’t necessarily mean that your dreams and goals are invalid or unachievable. If anything, rejection should motivate you to pay even more attention to what you set out for in the first place. After all, it is 20% what happens to us and 80% how we respond to it. Paying attention to distractions and in this case rejection, only serves to take attention away from the main prize.
Instead of focusing on your stumbles and falls, why not take some time off to cool down, re-evaluate yourself and appreciate your achievements? Doing so, is a major step in ensuring that your gaze is not taken off the prize. Learn how to prioritize and focus on the bigger picture.
3. Don’t take it personal
This is simply one of the most spoken phrases in the world, but it is also one of the most useful pieces of advice that a person could be given. So what if you have been rejected? It is part of life, everyone gets rejected. Rejection does not mean that something is wrong with you.
When you let yourself believe that you are inadequate and that something is wrong with you, you are simplyfeeding the low self-esteem monster. When you let low self-esteem take over, then you might as well say goodbye to the successful achievement of your goals. Always remember, that for you to be successful, you must believe in yourself even when others don’t!
4. Never give up
Few people have achieved success by trying once. In fact, most people who have achieved success in their various fields is because they have tried multiple times. The more you try, the more chances you give yourself of succeeding. Even Rome itself, wasn’t built in a day. Giving up signifies that you no longer believe in your capabilities and strengths. Giving up means that you are not ready to learn from your mistakes. Giving up means that you have accepted defeat. Instead, carry on with the struggle, put more effort, avoid the wrong turns that you made before and appreciate the fact that no one, absolutely no one, is perfect.
“Many of life’s failures are people who did not realize how close they were to success when they gave up.” – Thomas Edison
Rejection is an unavoidable part of life; it is bound to happen at one point or another whether we like it or not. But by being coachable, keeping your eyes on the prize, not taking it personal and pushing on even when the going is rough, you can ensure that your motivation levels are sky high even in the face of rejection.
Thank you for reading my article! What other tips would you give to stay motivated when facing rejection?
Image Source: thinkatheist | Útmutató a Léleknek
In a mother’s womb were two babies. One asked the other: “Do you believe in life after delivery?” The other replied, “Why, of course. There has to be something after delivery. Maybe we are here to prepare ourselves for what we will be later.”
“Nonsense,” said the first. “There is no life after delivery. What kind of life would that be?”
The second said, “I don’t know, but there will be more light than here. Maybe we will walk with our legs and eat from our mouths. Maybe we will have other senses that we can’t understand now.”
The first replied, “That is absurd. Walking is impossible. And eating with our mouths? Ridiculous! The umbilical cord supplies nutrition and everything we need. But the umbilical cord is so short. Life after delivery is to be logically excluded.”
The second insisted, “Well I think there is something and maybe it’s different than it is here. Maybe we won’t need this physical cord anymore.”
The first replied, “Nonsense. And moreover, if there is life, then why has no one has ever come back from there? Delivery is the end of life, and in the after-delivery there is nothing but darkness and silence and oblivion. It takes us nowhere.”
“Well, I don’t know,” said the second, “but certainly we will meet Mother and she will take care of us.”
The first replied “Mother? You actually believe in Mother? That’s laughable. If Mother exists then where is She now?”
The second said, “She is all around us. We are surrounded by her. We are of Her. It is in Her that we live. Without Her this world would not and could not exist.”
Said the first: “Well I don’t see Her, so it is only logical that She doesn’t exist.”
To which the second replied, “Sometimes, when you’re in silence and you focus and you really listen, you can perceive Her presence, and you can hear Her loving voice, calling down from above.”
– Útmutató a Léleknek.
One of the explanation of this conversation can be about our Mothers and also our Mother Earth, without her we would not exist and that is why we should look after our Mother Earth. She doesn’t need us to exist but we need her.
“Climate change is not a far-off problem. It is happening now and is having very real consequences on people’s lives. Climate change is disrupting national economies, costing us dearly today and even more tomorrow. But there is a growing recognition that affordable, scalable solutions are available now that will enable us all to leapfrog to cleaner, more resilient economies.”
– The United Nations.
We’ve all read a lot of literature about how we can save energy and decrease pollution from our school days. But the best way to combat climate change is if we all combat it together. Like charity, activism begins at home. Here are a few well-known yet rarely-followed methods which can help save our future. They will seem mundane and small-scale, but when thousands of individuals join together it will definitely dent an impact.
1. Walk the talk – literally. Try carpooling but also walk more often whenever you can afford to. You’ll be saving fuel and decreasing pollution. Also, it’s healthy, economical and reduces stress.
2. Eat wisely. The correlation between action against climate change and personal hygiene is well-documented. Avoiding processed items and reducing the consumption of meat will help in curbing global warming. This is due to many reasons, mainly because 18% of greenhouse gases are caused by livestock farming.
3. Drive slow and steady. When on the road, don’t drive recklessly, cut down your speed, and fix that broken engine. Not only will this increase the efficiency of your vehicle and ensure your safety, but it’ll decrease 25% of CO2 emissions.
4. Choose renewable power. Green energy, wind farms, CNG etc. There are many alternatives that are safer, healthier and more productive.
5. Adopt energy efficiency. Again, something we’ve heard from innumerable sources and yet mostly forget. Switch off the lights when not required, adopt LEDs, unplug your appliances when not in use, air-conditioners are CFC hubs so buy energy-efficient ones, embrace green energy etc.
6. Take shorter showers. Use less water for your showers, and save water in any way you can.
7. Plant a tree! Really, this method is a solution to so many problems that we face today. And there’s no need to explain why.
8. Get informed & get involved. Research more on the issue – the internet is your limit, and the internet does not particularly have a limit. Browse for more ways in which you can contribute, and spread awareness, urge your friends and family members to join you.
This World Ozone Day, let us promise to commit ourselves to protecting our natural resources and fighting climate change.
“The Man Who Knew Infinity”, is a biopic on Indian mathematician Srinivasa Ramanujan, which is going to have its opening at the Toronto International Film Festival (TIFF) 2015.
After the biopic of the young Indian mathematician makes its way to theaters, he’ll take his place next to history’s greatest minds like Sir Isaac Newton & Professor Stephen Hawking.
Srinivasa Ramanujan Iyengar (1887-1920) is hailed as an all-time great mathematician, like Euler, Gauss or Jacobi, for his natural genius, has left behind 4000 original theorems, despite his lack of formal education and a short life-span. He was an Indian mathematician and autodidact who, with almost no formal training in pure mathematics, made extraordinary contributions to mathematical analysis, number theory, infinite series, and continued fractions.
In 1911 Ramanujan published the first of his papers in the Journal of the Indian Mathematical Society. His genius slowly gained recognition, and in 1913 he began a correspondence with the British mathematician Godfrey H. Hardy that led to a special scholarship from the University of Madras and a grant from Trinity College, Cambridge. Overcoming his religious objections, Ramanujan traveled to England in 1914, where Hardy tutored him and collaborated with him in some research. As recently as 2012, researchers were finally proving and finding applications for mathematical theories he wrote on his deathbed, which Ramanujan claimed came to him in dreams.
During his short life, Ramanujan independently compiled nearly 3900 results (mostly identities and equations). Nearly all his claims have now been proven correct, although some were already known. He stated results that were both original and highly unconventional, such as the Ramanujan prime and the Ramanujan theta function, and these have inspired a vast amount of further research. The Ramanujan Journal, an international publication, was launched to publish work in all areas of mathematics influenced by his work.
Some of this work is being used in the study of black holes, which were decades away from being theorized when Ramanujan died in 1920.
Source: The Logical Indian
Worrying thoughts are easier to battle if you are at least on a level playing field. So what can you do to combat anxiety?
Source: The Conversation
By Adam Heenan, Queen’s University, Ontario
Anxious people tend to perceive their world in a more threatening way. That is, the more anxious a person is, the more likely they are to notice threatening things around them. This is called the threat bias.
Some researchers believe that the threat bias makes it harder for people to get rid of anxiety disorders because they get stuck in a loop – they feel anxious, they start noticing threatening things in their environment, and this in turn makes them even more anxious.
However, the threat bias isn’t just something that people with anxiety disorders experience. Everyone can have trouble keeping worrying thoughts and feelings of anxiety out of their minds. And there are things you can do to make it easier for your brain to inhibit worrying thoughts.
Why inhibition is good for you.
Scientists think the threat bias exists because anxiety affects our inhibition, which is our ability to stop thoughts or behaviors from happening. A person with good inhibition, for example, would be better at refusing dessert when trying to diet, because they have an easier time inhibiting that behavior. Our ability to inhibit depends on our ability to pay attention and stay focused. When people are really anxious, inhibition becomes difficult.
Having trouble focusing your mind can make it harder to inhibit certain thoughts. For instance, children and adults with attention deficit hyperactivity disorder (ADHD) have difficulties with attention and inhibition. Imagine putting a dish of candy in front of a group of children and telling them not to touch any. While some children won’t eat the candy, children (or even adults) with ADHD would find this more difficult because they would have a harder time inhibiting this behavior.
In fact, this is why medications like Ritalin or Adderall are helpful in managing ADHD. These drugs are psychostimulants, which means they provide the attention boost people with ADHD need in order to decrease certain problem behaviors and help improve concentration.
Searching for danger
But what about anxiety? Well, some researchers think that increased anxiety makes our brains search for danger.
Imagine being home alone, hearing a creak or a strange noise, and expecting a burglar to jump out at any second. This adaptation is useful because it ensures that you are ready in case there really is someone sneaking up the stairs. Overusing this system, however, can mean that people are anxious all the time, leading to fatigue, racing thoughts, and physical symptoms of anxiety like restlessness, insomnia or irritability.
But most of the time, a creak is just a creak, not a burglar about to leap out of the shadows. But what is the cost if you always feel this anxious? Researchers have found that people who are more anxious tend to have poorer inhibition, which means they have a harder time stopping anxious thoughts.
When this threat-detection system goes into overdrive it can cause serious problems and significantly deteriorate how well people function: like flashbacks in post-traumatic stress disorder or intrusive thoughts in obsessive-compulsive disorder.
In our lab we had participants complete something called a Go/No-Go task. We presented a series of letters on a computer screen and the participant’s job was to press the space key only when they saw the letter X, which occurred 75% of the time.
People often made mistakes and pressed the space key when they saw letters other than X. This gave us a way of measuring of how well people were able to inhibit their response to press the space key when other letters came up (i.e., the No-Gos).
We also measured our participants’ social anxiety using a questionnaire, and measured their threat bias using a visual perception task.
We found a link between a person’s level of social anxiety, their level of threat bias and their inhibitory ability. People who were more anxious tended to have poorer inhibition and this poorer inhibition was associated with a greater threat bias. This supports the argument that anxious people are unable to keep threatening thoughts from entering their conscious awareness.
Keeping worry at bay
So what does this mean for you? Anxious thoughts often pop into our heads. What our research suggests is that improving our brain’s ability to inhibit thoughts and behaviors should also help with keeping out worrying thoughts. Think back to that creaky house. If you were able to inhibit those worrying thoughts a bit better, you would be less likely to jump to the conclusion that a burglar is in the house every time you hear a noise.
One way to help your inhibitory ability is to get enough sleep. People who are overtired don’t have the attention or focus needed for proper inhibition. If you are lacking a few hours of sleep each night, you will be less likely to inhibit worrying thoughts from entering your mind.
Exercise helps, too. In previous research, we discovered that just 10 minutes of exercise or relaxation techniques led to people to perceive their world as less threatening.
Alcohol might initially help you fall asleep, but it can disrupt or delay rapid eye movement (REM) sleep. This part of our sleep cycle is associated with dreaming and with forming memories. Therefore, your cognitive abilities will typically be much stronger after a night where you didn’t drink (but you knew that, right?).
Worrying thoughts are easier to battle if you are at least on a level playing field. So try and rest up! Get some exercise! And next time you start to worry, consider whether those thoughts are really crossing your mind because the phone bill could mean life or death, or whether you are exhausted and just can’t keep those thoughts away.
Adam Heenan does not work for, consult to, own shares in or receive funding from any company or organisation that would benefit from this article, and has no relevant affiliations.
Joseph Proietto, University of Melbourne
The need to find fuel to generate energy is a profound drive within the biology of all living organisms: we all need food to survive. So it’s not surprising that our bodies have such a complex system to control food intake, driven by hormones.
Hormone levels also change when we lose weight. As much as we battle to trim down via diets and eating patterns, they’re also the reason most of us will regain the weight we lose – or more.
The body’s system for regulating food intake is coordinated by the hypothalamus, which is located under the midline of the brain, behind the eyes:
Within the hypothalamus are nerve cells that, when activated, produce the sensation of hunger. They do so by producing two proteins that cause hunger: neuropeptide Y (NPY) and agouti-related peptide (AGRP).
Quite close to these nerve cells is another set of nerves that powerfully inhibit hunger. They produce two different proteins that inhibit hunger: cocaine and amphetamine-regulated transcript (CART) and melanocyte-stimulating hormone (αMSH).
These two sets of nerve cells initiate and send hunger signals to other areas of the hypothalamus. So, whether you feel inclined to eat or not depends on the balance of the activity between these two sets of neurons.
But what determines which set of neurons dominates at any given time?
The activity is mainly controlled by hormones that circulate in the blood. These come from tissues in various parts of the body that deal with energy intake and storage, including the gut (which receives and digests the food), the fat (which stores the energy) and the pancreas (which makes hormones that are involved in energy storage, such as insulin).
Hormones in the blood
Let’s take a closer look at how each of these blood-circulating hormones work.
Ghrelin is made in the stomach. It stimulates hunger by entering the brain and acting on the neurons in the hypothalamus to increase the activity of the hunger-causing nerve cells and reducing the activity of hunger-inhibiting cells. As the stomach empties, the release of ghrelin increases. As soon as the stomach is filled, it decreases.
Insulin-like peptide 5 (ILP-5) was found to stimulate hunger in 2014. It is the second circulating hormone to have this effect and is mainly produced in the colon. But we still don’t know its physiological role.
Cholecystokinin (CCK) is produced in the upper small bowel in response to food and gives a feeling of fullness. It is released soon after food reaches the small bowel. Researchers have found CCK can stop a mouse from eating as soon as it’s injected into the brain.
Peptide YY, glucagon-like peptide 1 (GLP-1), oxyntomodulin and uroguanilin are all made from the last part of the small bowel and make us feel full. They are released in response to food in the gut.
Leptin is the most powerful appetite-suppressing hormone and is made in fat cells. It was discovered in 1994. The more fat cells we have, the more leptin the body produces.
Amylin, insulin and pancreatic polypeptide are made in the pancreas. Studies in the United States have shown that when insulin enters the brain it inhibits hunger, telling the brain “there is enough energy in the body, take a rest”.
Amylin, discovered in 1981, is made in the same cells that make insulin (the beta cells). It has been shown to inhibit food intake.
The exact role of pancreatic polypeptide is not yet known, but there is evidence that it inhibits hunger.
Once full, the stomach reduces the desire to eat both by lowering ghrelin production and by sending a message to the hypothalamus. Ghrelin levels reach a low around 30 to 60 minutes after eating.
Levels of hormones that make us feel full – CCK, PYY, GLP-1, amylin and insulin – all increase following a meal to reach a peak about 30 to 60 minutes later.
All the hormones then gradually return to their fasting levels three to four hours after a meal.
How weight loss affects our hormones
Several studies have found that diet-induced weight loss is associated with hormone changes that, together, promote weight regain.
Following weight loss, leptin levels decrease profoundly. Other hormonal changes include increases in circulating ghrelin, GIP and pancreatic polypeptide and reductions in PYY and CCK. Almost all of these changes favour regaining lost weight, by increasing hunger, reducing satiety and improving the capacity to store fat. These hormonal changes seem to be present for at least one year after weight loss, leading to a persistent increase in hunger.
These findings suggest suppressing hunger after weight loss – preferably with a replacement of hormones – may help people maintain their new weight.
Several of these agents have recently been approved by different regulatory bodies in the United States, Europe or Canada, but only one – liraglutide – is a version of one of the naturally occurring appetite suppressants (GLP-1). The ideal medication to maintain weight loss would be a long-acting mixture of three or more of the blood-circulating hormones we examined above: leptin, amylin, GLP-1, PYY, CCK and oxyntomodulin.
But producing such a mixture is proving a considerable challenge, so researchers continue to investigate how this might be done.
This article is part of an occasional series, Chemical Messengers, on hormones and the body.
Joseph Proietto is Chair of The medical Advisory Board for Liraglutide 3mg for Novo Nordisk. He receives funding from the NH&MRC.