The fast answer to it. Is that we eat more than we should. But why is it so? It`s mainly because we don`t eat enough vegetables, because when you eat the receptors in our stomach helps us decide when you have gotten enough food, these include stretch reseptors which among other things helps us decide how much space the food is taking, we also have density reseptors that let us determine the calorie density of the food we eat or what we more commonly call the richness of our food.
As the picture shows above we need a lot more meat then vegetables for our stomachs to feel filled, even worse with oil. Not to mention all the other negative side effects by eating too much meat and processed food.
Now you may ask how does sugar come in the picture? The answer is simple. Sugar is made up of two molecules, Glucose and Fructose they are different and the body handles them differently. Glucose is an energy source that can be metabolized by any organ in the body including the brain. Fructose however can only be metabolized by the liver. When you consume sugary beverage the fructose is flooding in your liver. As an effect the liver is overwhelmed and start to convert the sugar to fat. All these excess sugar to fat conversions can increase the risk of having fatty liver, diabetes and heart disease. The important thing to remember when you eat sugary food and beverage is that you consume them slow and in small amounts for not to create a tsunami effect where you overwhelm the liver with sugar.
Words to know: Metabolized to change (food) into a form that can be used by your body : to process and use (substances brought into your body) by metabolism.