Lately I've received a whole bunch of questions about the benefits and drawbacks of insulin, so why not straighten out the issue, once and for all? (Unfortunately, most of this doesn't apply to diabetics, but if you're one yourself you probably knew that already.)
Insulin release is mainly a bodily response, caused by the food you eat. You are able to control this factor to a pretty large degree, just like you can control whether or not you get goose-bumps by making sure to wear a sweater when it's cold - even though the goose-bumps in and by themselves isn't something you can control. You can't choose to have high or low levels of insulin floating around in your system, but you can pretty much steer it by eating. A truckload of fast carbs (like Dextrose), a big bowl of rice, and an extended period without food will all have very different impact on your Insulin levels. But let's not rush ahead of ourselves here - let's get the big picture together.
Fast vs. Slow Carbs
As you probably know, carbs are actually plain sugar. As an experiment, chew on a piece of non-sweet bread for a while, and you will notice an increasing sweetness developing, because your saliva and jaw-action is breaking down the large chunks of sugar into smaller units, which in turn gets noticeable as they get smaller and smaller. This is how it works in your stomach as well. Now, the difference between slow and fast carbs, aka. complex and simple carbs, is how big the chunks of sugar are!
Assume that you have a handful of loose powder. In your stomach, there's really not anything more to digest, so the whole bunch gets launched into the blood stream, which the whole point of eating in the first place, but in this case it all gets launched at the same time, causing a HUGE, sudden surge of blood sugar! Complex carbs, on the other hand, is more like having a ball of yarn in your hand - it won't just "come apart" anytime soon, but needs to be stripped little by little. This equals a nice and even release of sugar into your blood stream.
Insulin To The Rescue
Now, what's the big deal about how fast it goes into the blood stream you may ask? Well, as a general rule, all sudden changes involving the body is bad. This is no difference. The body takes a beating from extreme levels of blood sugar (the eyes is only one such area - diabetics often develop eye problems as they grow older, simply because their regulatory system for blood sugar is out of synch), so in order to protect itself the body releases it's first, last, and only defense against the scum of the blood stream: Mr.Insulin!
Mr. Insulin is an efficient fellow, rapidly stomping down the blood sugar and thereby saving the body. The bad news is that he's a wee bit over ambitious about it, and usually slashes it down to a level BELOW where it was before eating the food. Now, if you were tired and had low blood sugar before, where do you think you end up half an hour after that candy bar, when Mr.Insulin has done his thing? Say hello to the common afternoon crash.
How does this work?
The Insulin basically force-feeds the muscles with the excess sugar, which they don't like. The amount of sugar being "let in" into the muscles depends on the level of insulin released, which in turn is determined by the insulin receptors in the muscles themselves. Think of it as a dude who listens to how hard Mr.Insulin knocks on the door to determine how wide he should open the door. Another feature of Insulin is that it is highly anabolic - it's a good friend and ally if you're an ectomorph trying to gain some mass (with moderation though, I should say. No insane 100%-sugar diets please!).
The BAD news is that it automatically shuts down your fat burn capacity and keeps it in low gear for quite a while, while actually promoting fat storage! The logic behind this is pretty simple if you remember why insulin is out there in the first place: With this massive dose of sugar going out into the blood, the body makes the assumption that it's getting a truckload of food (before the days of processed food, it was hard to achieve this kind of sugar-boost without extreme eating, so it makes sense). Since the load of food is obviously so significant that you need to store EXCESS energy (as in shoving it into the muscles), what kind of moron wouldn't grab the opportunity to refill the other form of energy storage: Your body fat! By the same token, what would be the need to set things up for fat LOSS in this scenario?
What the body does
By now one would think that the body would recognize its mistake pretty quickly and correct itself, but this is the part where you sort of get it in the shorts - it won't! At least not for a while! So, to sum it up, you get a sudden blast of sugar in your system, and Insulin is released to protect you from it. The Insulin grabs all the sugar and shoves it into the muscles (who doesn't like it), shuts off the Fatburn-switch, and turns on the Fat Storage-switch.
But since what the body thought was a major load of food really turned out to be only meek little candy bar, there IS no surplus to handle after that initial blast of sugar ended, so you end up with an empty stomach and even lower blood sugar levels. Normally the body would compensate for this by tapping some stored fat, BUT? The ever-helpful Mr.Insulin made sure to turn that switch off, so what does the body have left? Protein. More specifically - MUSCLE protein. If you shudder as you start seeing what I'm getting at, please keep doing it. You should.
Muscle protein can be used as emergency fuel, especially - remember this? - in a situation where the body perceives itself as starving. Then it wants to get rid of tissue that burns calories 24/7, which leaves us with muscle, being most "un-economical" from a calorie-perspective (even though you surely likes that the extra muscle you're packing makes you able to get away with that Saturday cheese burger, by simply burning the extra calories during the week as maintenance). It might seem paradoxical about the body both thinking it starves at the same time as it shuts off its fat burn because of anticipated truckloads of food. It is. But there's nothing you can do about it. See? I TOLD you that you'd get it in the shorts! Next week we'll have a look at how to get a better process going, and how this relates to maximizing the benefits of Creatine.