Question one, how does a slim person or child actually processed food? In this section, we will look at what's normal in slim, healthy person. We'll look at what happens to the food, and how does the body process the energy from the food. And we'll also look at hormones and how hormones act on our energy processes, and why these hormones are important and how they impact on whether or not we gain or lose weight. Now, all of this information is important because understanding the energy balance will ensure we have control on whether or not we gain weight, or maintain our present weight, or in fact even lose weight. It's also an introduction to inside of ourselves and the goings on there.

The more we understand, the more informed our choices will be when faced with a loaded buffet table. So let's get back to the beginning. At the beginning, we each have a unique basal metabolic rate, or BMI. BMI stands for basal metabolic index. And I want to explain exactly what that is. The BMI is the minimum energy, the body needs to keep our heart beating, our lungs working, and ourselves dumping waste, as we do something so simple as lying on our bed reading our book.

Then on top of that, we require energy to get up to go to the kitchen to eat, or to climb stairs, for example, or to do something more active like going to the gym. So the metabolic requirement is not static at all. It changes hour by hour, it changes day by day, and of course it changes year by year. And just to throw in a curveball, our BMI is not only influenced by our activity, but it's also influenced by our homelands. genetic inheritance and immutable factors, such as age. So think about hormones as the body police, who scurry around, watching and monitoring everything, and giving feedback so that our organs and our brain know what's going on in our body, and know what hormones enzymes to release when it's necessary for a producer.

Now, we all understand that walk upstairs, for example, requires some energy, and our body uses food to fuel this particular energy requirement. But in actual fact, once the food is digested, it's still inert in our body. It has to go to the energy factory to be converted into an energy source that our body can actually use. And the energy factories in the body are called mitochondria.