Of even more worry than glucose in the modern diet is fructose. Most refined sugars contain a significant portion of fructose in addition to glucose. Many people revile high-fructose corn syrup as being a great evil in the world of food, but the truth is that even regular table sugar is 50% fructose (the aforementioned high fructose corn syrup is 55% fructose, a scant 5% higher--realistically speaking, table sugar is just as bad).
Agave nectar is even worse, running as high as 85% fructose in some batches! As with fat, fructose is not truly the enemy here--overconsumption of that sugar is.
The issue with fructose is that our body cannot use it directly as energy, vastly preferring glucose as its sugar fuel source. While glucose will begin circulating in the blood almost instantly after absorption, providing energy to our brain, muscles, and other organs, fructose gets metabolized by the liver instead, first into glycogen (a form of short-term storage) if it is needed, and then into fat.
Key Point: If too much fructose is consumed at once, our liver is overloaded, and more fructose will end up as fat.
When we consume processed food, the sugar content is usually significantly higher than what is found in nature, and is released much faster (as a result of low to no-fiber content). The average can of soda contains more sugar than two apples, and the sugar it contains is completely absorbed by our small intestine within 5 minutes.
A small cake or cookie can be completely broken down and absorbed in twenty minutes once it enters the small intestine. Even if the food is low-fat, the end result is still a rise in free fatty acids in the blood, as the sugars get metabolized into fat to be stored!
Why You Must Avoid Processed Foods To Burn Belly Fat
To make matters worse, many processed foods tend to be high in both fat and sugar, a nightmare for insulin resistance. Now, free fatty acids are being elevated from two ends of the spectrum, and there is a good chance that much of the excess energy (especially from the fat) will be stored instead of burned, leading to obesity as well.
This extra weight will then play its own role in the formation of insulin resistance, creating a dangerous cycle.