A20 The Body Needs to fast to be healthy.

Chapter 20 burning fat, the details

in this chapter we'll look very closely and how the body breaks back down. To make energy, the body must first break down more complex foods, such as starch, protein and fat into simple molecules. Those simple fields are cut in half and added to oxygen from the air you breathe, and this releases energy. The waste products from burning these fuels are water and carbon dioxide, which go into your blood to be excreted in the urine, or exhaled via the lungs.

All the complex molecules are broken down to either glucose which is the simplest form of sugar, or to ketones, which are the simplest burnable form of fats. Those are the only substances that for our purposes, we can create energy from

the stages are as follows. In the Fed state, after a meal, glucose is burned because it is readily available. Also in the Fed state. Extra glucose is built up into bigger molecules, ultimately becoming fat, which is stored in the body.

In the intermediate, temporary hunger state, the brain starts telling you to seek food,

the natural instinct of the knifes This is slightly uncomfortable. It is after all, a warning to not run out of food. This worked well when we lived at times when we were not surrounded by cheap and easily accessed foods.

It tends not to work so well now, because we're spoiled with our choice of foods, especially of cheap snacks. However, if you don't eat, this doesn't mean that hunger will continue.

Enough this smarter than that, as we discussed earlier. If you remain unfed through this temporary intermediate state, then your brain tells the body that glucose is low, and that it should start burning fat to make energy. So in the fasting state, which happens more than 12 hours after a meal, fat start getting broken down, and ketones are made, which are then burned for fuel. The brain is quite happy to use ketones for fuel as it the rest of the body. Hunger goes down because the brain's instincts have detected now that you have fuel on board. This process continues until the next time you eat.

starvation is when you have very little fat left to burn. This is very uncommon in most people with adequate nutrition in economically adequate countries.

It doesn't happen in fasting. It's seen in undernourished people. At this point, the body starts to scavenge fuel from other sources. There's no carbohydrates around no fat, so the body starts to break down proteins which are found in muscle. If this continues, the body begins to waste away and your appearance is easily noticed as that familiar sight of very thin gaunt people with sunken eyes and their skin hanging over the skeleton. If it becomes extreme, the belly swells up because proteins are essential in connective tissue. And the soft belly just tends to expand when there isn't enough protein around to the athletes and bodybuilders and worried young men, you don't have

to worry about burning away your muscle mass protein. Most of your fat stores need to be depleted first.

It's a myth to suggest you lose essential muscle protein during normal fasting. In fact, about 12 hours to 16 hours after the fast the brain also secretes growth hormone, which prevents protein from being burned. The body burns up fat before resorting to use up the protein. People may feel weaker in the gym during fasting. And they may even lose weight. But this is because of two reasons. Firstly, carbohydrates are stored along with water. Having less carbohydrates around means that you weigh less because that water element is also not required. So your body gets rid of it. So you weigh less.

Also less carbohydrates means that there's less of that immediate explosive energy that comes from having excess carbohydrates in your system that we talked about earlier. So you may feel weaker in this explosive sense. But this is not due to protein depletion or weakened muscles. It's simply because your body doesn't have all that excess sugary energy ready to burn immediately.

When the body burns ketones, it does so in a moderate and steady way exactly according to what it needs.

doesn't create excess energy, because this would be wasteful.

The body doesn't know after all, whether you are missing food deliberately, or if there's really no food to be found. So takes a cautious route, only burning as much fat as you need in that period. You can do some exercises to speed this process up, and we'll learn about this later. Don't worry, it's good news. Just like the advice on food. The exercises we will talk about are dramatically different, less time consuming, and far less demanding than that sweating and like rubberband, gym machine routine that we imagine we have to do. Our exercises will be easier to integrate into your life than those heavy handed long exercises.

Let's talk about fat adaptation. It's a special state.

This is a state that comes some days after you've been fasting regularly. In fact, adaptation your body has now set itself up properly to burn fat as a preferred fuel. This happens at a molecular level. There are all sorts of different chemicals and genetic processes and other structural alterations that the body makes when you are burning fat instead of sugar. These takes some time and energy to build up properly. So the body initially just does the bare minimum of making these changes if you just fast for a short time.

Once it becomes clear that you're fasting for a number of days, and the body goes all out in changing the shop floor if you like to be more efficient at burning fat

End of Chapter