Ok, this is sorta my theory. But im not even sure if it isnt already proven or already someone elses theory or even if it has any truth to it at all.
As soon as one ingests food, we begin to digest it. Now when we eat simple sugars the body processes it very quickly and have a larger concentration of these sugars throughout our bodies. When we ingest complex carbs it takes longer to digest and it is a more steady release into our blood stream. Now the body looks at everything instantaneously so the body is always trying to figure out to what to do with the calories. If there is a need to use the sugar for energy then it will burn them for energy, if there is not need at that time then it will store it. That is why ingesting 100 grams of simple carbs vs. 100 grams complex carbs are very different. With the simple sugars, the body will have a lot more at one time because of it being processed faster and that means that after you burn and refill the glycerin stores it will be stored as fat and then you will have no sugar in the blood and feel hungry and lethargic. With the complex carbs, there is a slower processing of the sugar and less of an insulin spike. Therefore instead of having 100gms of sugar in the blood for an hour, it will be spread over 4 hours (im just using the times as an example) This allows you to eat more of these calories without having to worry about fat storage. As far as eating fat with your meals that have carbs it is the same thing. If you have too many "calories" in your blood you will store some as fat and the fat will only add calories to that concentration. If you eat fat with simple sugars you will have even more calories in your blood faster as well as an large increase in insulin which is not good as far as fat storage is considered, and if you eat them with complex carbs it will be a slower release into the blood stream with a smaller increase in insulin.
I know that this is probably confusing since i am sorta typing as i am thinking and i am more than sure that there are many problems with this but i was just wondering what everyones take on this is.