Carbohydrates
Although carbohydrates are the most common source of energy in humans, the simple fact is, there is not a single carbohydrate that is essential to human life.
Carbohydrates are classified into two types: Simple & Complex.
Simple carbohydrates are also known as simple sugars. Simple sugars are those found in refined sugars (and the foods they are made with like cookies, candies, etc) but also in food like fruit and milk.
Complex carbohydrates are known as starches. Starches include grain products such as cereals, bread, pasta, crackers and rice. Like simple carbohydrates, complex carbohydrates can be refined or left unrefined. Refined carbohydrates are considered to be less healthy as the refining process strips away much of the vitamins, protein and fiber. Unrefined carbohydrates cause less insulin spike and because of that, they are considered to be the most healthy of the carbohydrates.
Regardless of whether the carbohydrates are simple or complex, they both cause spikes in blood sugar. As you will see shortly, these spikes in blood sugar are the #1 cause of unwanted body fat.