Different Types of Hunger
Part I
The brain draws energy from one of every 3 calories we ingest. And the brain needs a continuous supply of energy. Without it we would rapidly lose consciousness and die. So hunger is a very important alarm bell for the brain when our stored energy runs out.
When might this stored energy run out?
Lacking supermarkets, refrigeration and take-out, our ancient (and not so ancient) ancestors frequently faced food shortages. They had no tinned goods or frozen foods to turn to. If war or weather meant their food source was spoiled they faced prolonged periods of deprivation. So how did these humans survive for extended periods without food?
They relied on stored fuels for energy. These stored fuels came in 3 types: carbohydrate, protein and fat. Carbohydrate is stored mostly in the liver, protein mostly in muscle. However these stores are small. Even a very muscular man (think big Arnie Schwarzenegger in his prime) would waste away in days with no food —without, that is, the third type of fuel: fat.
Fat is such an efficient energy store that most adults have enough body fat to survive several weeks. And fat was therefore the way many of our ancestors stayed alive during times of scarcity and deprivation. Energy was released by the fat cells to keep a steady amount of calories accessible to the brain. (Even in the modern healthy human, fat is estimated to provide as much as 60% of the energy we use at rest).
So what about the modern day?
We have established that the human body can go for some time without food, and that fat is essential to providing energy between meals. We understand how the brain needs continuous energy, and that fat is the solution to this. If we have plenty of fat and there is no danger of energy running out what then, you may ask, causes our hunger every day?
Hunger occurs on many levels. (You did not expect it to be simple did you?!)
You’d recognise physiological hunger by a rumbling and “gnawing” feeling in the stomach. These are the body’s cues for us to take on board some fuel. This sensation is controlled by no less than eight hormones! And the master controller of these hormones is insulin. When insulin is high we feel physiologically hungry.
Alongside this, modern life presents different challenges: we have plenty of body fat and plenty of food. Instead of food shortages we often face lack of:
control
a sense of importance, of feeling valued, of making a difference
love, social and spiritual connection
growth and stimulation or variety in our days
With so much food around it easy for us to turn to it to fill the gaps previously filled perhaps by stronger communities, spirituality, connection and sense of purpose or wellbeing. Some experts would even classify these gaps as a type of hunger themselves. Certainly we can often mistake these gaps for being genuinely hungry for food. (A good way of checking is next time you go to prepare some food notice what you are feeling. You can still eat the food. But after you eat it notice if that feeling has changed).
The next blog, What Makes us Hungry Part II, will explore how we can control how much insulin we have in our bodies…. and therefore control our physiological hunger.
Don’t miss it!
