I recently read that the average adult has about 1 teaspoon of glucose (sugar) in his or her bloodstream at one time. That’s a normal size adult with a normal blood glucose level. So that’s about 4.2 grams of sugar dissolved in the bloodstream at any time. It doesn’t seem like very much but even a small excess of sugar (glucose) in the blood, if present for a long time, can start to cause all sorts of damage.
People with poor blood glucose control, be they type 1 or type 2 diabetic, or even pre-diabetic, are at risk for all sorts of medical problems: kidney disease, heart disease, hardening of the blood vessels, loss of vision, nerve damage, poor blood circulation – to name a few. That is why when we consume sugar, in any of its forms, the pancreas secretes insulin to transport the sugar (glucose) out of the bloodstream and into cells where it won’t cause harm.
So what does our body do with the sugar we consume? Some of it will be used as fuel to support our immediate metabolic needs. Some of it will be stored as glycogen in the liver and muscles. Our brain will burn a significant portion of it and store a small fraction of it in glial cells (a type of nerve cell). The average brain can go through about 500 Calories of glucose a day. You may have heard that the brain runs only on glucose. Well, that’s not entirely true. The brain needs a minimum of about 20 percent of its Calories from glucose, but it can actually run mostly on ketones, another type of fuel that our body can use. Our red blood cells run exclusively on glucose. If there is excess sugar present after all this it will be stored as – fat. Yes. Fat. It’s important to remember that this is a dynamic process. We are constantly consuming and expending energy, and hopefully if the intake matches the output, our weight stays constant and we don’t get fat.
So why are so many of us overweight and obese? Well. While inactivity definitely contributes to obesity, it turns out that the answer is a little more complicated than “calories in = calories out.” Visit again on Thursday when I’ll post “part 2” to answer this question.