Constant fat-burning is how our bodies are designed to operate, but it is certainly possible to throw a monkey in the matrix and burn only glucose, forcing our bodies to store more and more fat until we blame the dryer for shrinking our pants. I’ll go over nutritional sabotage in the next post, but for now just picture filling your car up with rocket fuel. It doesn’t make your car go faster—it just burns up your engine.

Now that we’ve established how our bodies burn fat and glucose for energy, and that we are designed to use fat as our primary fuel source, using glucose as a secondary fuel during intense activity, I’ll explain how this dynamic can be reversed, causing the body to stop burning fat and preferentially burn glucose, forcing us to store more body fat.

When glucose hits your system it triggers your pancreas to produce insulin. This is commonly referred to as the body’s glycemic response. Your body needs the insulin as a catalyst to enable your cells to burn glucose for energy. And this insulin response is a good thing. Our bodies are diesel engines, and glucose is gasoline, rocket fuel, and if it’s left in your system for too long it becomes toxic. Once the glucose level in your blood (blood sugar level) gets high enough the body stops burning fat and switches to burning glucose exclusively as a measure of self defense. Any glucose unable to be immediately used is converted into free fatty acids and stored as body fat.

So excess glucose consumption puts us in double jeopardy. It causes us to stop burning fat, and it also causes us to store fat. Passage to and from the fat cells is a one-way street; fat cells can either release fat, or store it, but not both simultaneously. When the body is finished burning the glucose we’ve just consumed, insulin is still coursing through our veins, and so long as insulin levels are high our cells can’t revert to burning fat.

With the glucose gone, and the cells unable to burn fat, our energy levels crash, and we feel lethargic and sleepy (sugar coma) until our insulin level can come back down. This process can take hours—and during this time it is impossible to burn fat, neither dietary fat we’ve just consumed nor stored body fat.

If we habitually subject our bodies to this condition we run the risk of developing a resistance to insulin, which can lead to metabolic syndrome and type II diabetes. But before these chronic diseases develop we will see a dramatic increase in body fat, simply because we have made it impossible for our cells to burn our own stored energy.

This is also why obese people eat a lot. They are positively ravenous because they cannot burn the fat around their middle, so their lean tissue cells are starving, crying out for immediate energy, which in the United States of Plenty typically manifests itself in gorging on sugar and non-fiber carbs (white bread, white rice, pasta, potatoes, etc.), which raises blood sugar, which raises insulin, which means any fat consumed cannot be burned, so is instead stored as body fat, and any glucose that is not immediately burned is also stored as body fat—body fat which cannot be used by the cells as energy until insulin levels go down, but before that happens the cells will have used up all the glucose they were able to and are demanding more energy NOW, energy that the fat cells, the UN Peacekeepers of the body, desperately want to give to the poor, starving cells but the Benevolent Facilitator Insulin has become an oppressive, diabolical warlord and is holding the energy hostage, so the obese person keeps his lean tissue cells placated with quick, black market energy sources (sugar and non-fiber carbs), all the while the once peaceful, thriving nation (our bodies) declines into a failed state (we get fat, and sweat a lot, and die).

Fat Cell: “Pardon me, would you be so kind as to let me get by? I really must deliver this energy.”
Insulin: “MuuuwwaaaahahahahahahaHAHAHAHAHAHAHAHA!!

How much glucose is too much? With a typical metabolism, a healthy person will have about a teaspoon worth of glucose in their bloodstream. Not much at all, considering we have around ten pints of blood in us. If that amount drops, the body will release glucose stores from the muscles and /or liver to make up the difference, and if our glucose stores are depleted the liver will break down proteins to create the glucose it needs.

As little as half a teaspoon more glucose in the bloodstream for an extended period of time is enough to cause serious adverse effects. Our bodies go to a tremendous amount of effort to regulate our blood glucose levels, and indulging in sugar and non-fiber carbs is much worse than the concept of “empty calories” implies.

It seems to be a popular conception that carbs (glucose) are the body’s preferred source of energy because they will be burned before fat. This is precisely wrong.

The body will burn glucose first because it becomes toxic if left in the blood stream. We have to burn excess carbs in our system, and if we can’t (or don’t) burn them we will convert them into fat and store them before the glucose poisons us. Glucose is rocket fuel—a teaspoon’s worth will give us more speed, two teaspoon’s worth will burn us out from the inside.

Well gee, Patrick, thanks for the info and all, but what the hell am I supposed to eat if I can’t have pasta, or bread, or french fries? And aren’t carbs the cornerstone of civilization? I mean, we built the Pyramids with beer, and the Great Wall with rice, so I think I’ll just sit down and enjoy my big, fluffy muffin. Don’t tell me it’s not healthy—it’s got blueberries!

All valid arguments. For now my only response is it’s doubtful you built anything visible from orbit, the poor bastards who did are buried in that wall, the world’s largest monuments are also the world’s largest tombs, and anyway I’m fairly certain I saw on the Discovery Channel that aliens built the Pyramids, and everyone knows they only sip dark matter from tiny crystal teacups.

In my next post I’ll go over dietary fat, why you shouldn’t feel guilty eating it, and why butter is good for you.

Yes.  Butter.

After a few complaints of my last post being too long, I’m going to split this one up into small, easily digestible parts. Too long? I mean, the last post was like 2000 words—how did you people make it through college?

For the first part I’ll go over how our bodies burn energy, as well as the two types of energy we use for fuel.

Fat:

Fat is your body’s primary fuel source. We are constantly burning fat while sitting, sleeping, standing, walking—any light to moderate activity we engage in will burn fat. Obviously, the more intense the activity, the more fat we’ll burn. However, there is a point where we receive diminishing returns from fat as an energy source. The reason is individual fat cells are, well, fat. Only so many fat cells can fit through our capillaries at a time. As our activity level increases in intensity, our cells demand more energy, and past a certain point fat cells are literally too big to get through our capillaries in time to meet that demand. Think of fat as your body’s diesel fuel—low intensity, high mileage, endurance fuel. For faster, harder, and more intense, your body has to turn to glucose.

Glucose:

Glucose is your body’s high octane gasoline. It’s not a very efficient fuel, and you don’t get anywhere near the mileage as fat, but sometimes you just gotta go fast. Well, maybe not you, but your hunter-gatherer ancestors needed glucose to chase their dinner, and to avoid becoming dinner.

Your body prefers to burn fat rather than glucose. How do we know this? Because we store more fat than glucose. Our capacity for fat storage is nearly unlimited—the more we store, the fatter we get. Glucose, on the other hand, is stored primarily in the muscles, and there is a definite limit to how much glucose our muscles can hold.

A few of our body parts require glucose for energy, like the brain and red blood cells, and the glucose stored in our muscles can fuel our bodies for about twelve hours at rest. If we add intense exercise, a person in good shape will have about two hours worth of glucose to burn, depending on the type of activity. So what the hell does all this mean? Do we need to keep replenishing our glucose stores before they run out?

Good God no! What it means is despite all of our civilization, biologically we are still hunter-gatherers. We are designed to burn fat most of the day while we forage for nuts and berries on the way to the hunting grounds, burn even more fat as we jog around the wildebeest herd comparing notes with each other on which poor little gnu is the likeliest catch, and then burn even more fat mixed with some high octane glucose as we chase that delicious self-propelled barbeque down, stab the hell out of it like Caesar in the Senate House, and high-five each other while we drag it back to our cave.

That little hunting scenario is a good image to use to get a rough idea whether you’re burning glucose or not.  If you’re able to talk then you’re probably burning mostly fat.  If you don’t have enough air in your lungs to waste on idle gossip with your treadmill neighbor then chances are you’re tapping into your glucose reserves.

Typical Paleolithic Era outfit with an ergonomic design that allowed freedom of movement for hunting and gathering (post-Ice Age).

A big misconception I find most people have is that fat/glucose burning is an either/or situation, and to burn more body fat one should engage in low intensity aerobic activity. This is absolutely not true. Fat burning does not switch off just because your muscles start burning glucose—glucose is burned on top of and in addition to fat, and if your muscles are burning glucose it’s because you can’t possibly burn any more fat and keep the same intensity level.

Constant fat-burning is how our bodies are designed to operate, but it is certainly possible to throw a monkey in the matrix and burn only glucose, forcing our bodies to store more and more fat until we blame the dryer for shrinking our pants. I’ll go over nutritional sabotage in the next post, but for now just picture filling your car up with rocket fuel. It doesn’t make your car go faster—it just burns up your engine.