Why do you need to know about it?
Because how your body processes food, and how your body reacts to the food you eat is the key to everything.
Okay, but how does it work? What does your body do with what you eat? What effect does what you eat have on you? And crucially, what drives you to eat?
It all starts with motivation!
You have two prime motivators, hunger and reward. Let’s look at hunger first.
Motivator Number 1: Hunger
Why do you eat? You eat food because it gives you the energy you need to function, and the vitamins and minerals you need to maintain your body. Food contains calories which you metabolise and use to build muscle and bone – and to produce energy.
The food that you eat is a mixture of fat, protein, carbohydrate and fibre.
When you chew and then swallow food (calories) you start an amazing process.
The food you eat first passes into your stomach where hydrochloric acid is released. This breaks the food down into smaller pieces before it passes through into your small intestine, where digestive juices (enzymes) digest the food into even smaller pieces.
The digestive juices in your small intestine break down your food into three nutrients: fatty acids, amino acids and simple sugars.
Nutrients are the essential substances we get from the food we eat. They provide energy and supply the body with all it needs to perform its daily functions properly.
Dietary fats are broken down into fatty acids, dietary proteins into amino acids and carbohydrates into simple sugars – which is mostly glucose. Your small intestine’s job is to absorb these nutrients and send them to your liver for them to be processed into energy. Any fibre in your food is not digested. Instead, fibre does two things: it speeds the flow of food through your intestine and, importantly, it limits the rate of absorption of the three nutrients. More about the benefits of fibre later.
When the nutrients arrive at your liver, its job is to process them and turn them into energy. This causes a rise in your blood glucose level. The rise in blood glucose is picked up by your pancreas which prompts it to release a hormone called insulin.
Your pancreas is a very important organ which sits behind your stomach. It delivers digestive juices into your small intestine which helps to digest your food. It’s also responsible for releasing the hormone insulin into your bloodstream.
What is insulin? Insulin is most commonly known as the hormone that regulates blood sugar. Blood glucose is produced when your liver processes the nutrients it receives from your digestive tract – your small intestine. Your pancreas then releases just the right amount of insulin to match the level of glucose in your blood to ensure your blood glucose level is kept in balance: not too high, not too low.
Insulin is also your energy storage hormone. It takes the glucose from your blood and stores it for future use as glycogen. Some of it goes to your liver, some to your muscles. Then it takes the fatty acids in your blood and turns them into triglycerides (fat)