The Skinny on FAT

Insulin and Fat Breakdown - Peter Attia

Here is the SKINNY on FAT

When you eat food, any food, it must be digested. The function of digestion is to break down food into glucose molecules that can be transported to your cells by your blood. One of those processes involves your pancreas producing insulin, a hormone, in response to any carbohydrate ingested. One of the hormones involved in digestion is insulin, produced by the pancreas.

Insulin: That is the job of insulin – to effect the cells’ receptivity to glucose. Insulin is like a key that opens a gate in the cells to allow glucose to get inside to be used as energy. Our cells need energy for everything from breathing to keeping our heart beating, from digging ditches to washing dishes. Food is converted into glucose to be used for quick energy. But our bodies know that we may also need energy later, such as while we are sleeping when no food is available, so any excess glucose is stored in the cells as fat, more specifically, as free fatty acids. This occurs if we eat beyond our needs, say, at holidays. If we consume too much food for our needs, the excess glucose that is not immediately used for energy is stored in our fat cells as free fatty acids to be retrieved later, when food is not available.

The cycle goes something like this: Food enters the body, insulin is pumped by the pancreas, glucose is transported to the cells and out of the bloodstream. Insulin then decreases as it is no longer needed until it is completely gone, and our cells, having been fed and the excess glucose having been stored away in our fat cells, insulin now closes the doors to our cells. During the night, when we are asleep and not eating (fasting), our cells still require glucose to function. When we fast, it is the liver that becomes the source of the glucose, rather than food. The liver releases glucose from its storage area into the bloodstream to keep blood glucose in the normal range. So, insulin is necessary to help transport glucose to cells, and insulin also prevents the liver from dumping glucose into the bloodstream at inopportune times. All these processes help blood glucose levels return to normal after meals.

Another important function of insulin is to store fat. Take any diabetic with a blood sugar of 300. Give him or her a shot of insulin, and the blood sugar goes down to 100. Terrific. But where did those 200 points of blood sugar go? They didn’t simply vanish into thin air.

They got stored in the liver for later use as fat.

Stay with me here. When levels of blood glucose (and insulin) are high, the liver responds by absorbing glucose. It stores it in the form of glycogen. These bundles of glycogen now fill up the liver cells. The liver is like a warehouse for excess glucose. When glucose levels drop, so does insulin production. The shortage of insulin in the bloodstream is the signal the liver needs to start releasing its assets, sending its glucose stores back into the bloodstream to keep the cells well fed between meals and overnight.

If our body needs more energy (or glucose), such as during sleep or during a fast, if there is no food handy, the body turns to our fat cells that release free fatty acids as a source of energy that go into the bloodstream to feed our other cells. Fatty acids do not need insulin to open the cell doors; that’s why they are called “free” fatty acids.

When we consume a meal high in refined carbohydrates, like a doughnut, we get a sugar spike and the natural response is for the pancreas to produce insulin to mop up that sugar. This means that the insulin facilitates the transport of that glucose into our cells and out of the bloodstream. Our cells are fed, and any excess glucose is stored in our fat cells. But here is a wrinkle: The blood sugar level goes down fairly rapidly, but not the insulin itself: it remains high longer than the glucose it is meant to mop up. This creates a problem: As long as there is insulin still floating around in our body, we cannot access the free fatty acids from our fat cells. Remember, free fatty acids do not need insulin to get into the cells for energy; they need insulin to be gone from the bloodstream before they can leave the fat cells. In other words, as long as insulin is still present in the blood, the fat cells retain their free fatty acids, and you are not burning fat as energy.

Insulin Resistance: Refined carbohydrates raise blood sugar quickly and dramatically, while complex carbohydrates raise blood sugar more slowly. It’s blood sugar, regardless. When food enters the body, it must be digested. When the pancreas senses glucose in the blood, it sends out insulin, the hormone responsible for transporting glucose to any of three types of cells: liver cells, muscle cells, or fat cells. Insulin’s job is to act like a key, to open up the cells’ gate to allow glucose to go in. The result is twofold: It gets rid of (mops up) excess glucose in the blood, while simultaneously delivering glucose to your cells where it can be stored as energy. When you are insulin resistant, your cells do not respond to insulin as they’re supposed to: they do not open their gates, and glucose cannot get in. Consequently, glucose accumulates in the bloodstream, and remains high. Your cells are deprived of their energy source, you feel low energy and fatigue, and you now experience cravings for more carbs (sugar) because the sugar that is already present in your body is not allowed entry into your cells. Moreover, the pancreas now redoubles its effort to clean up the excess glucose that has been accumulating by producing even more insulin, and now what you have is hyperinsulinemia (high insulin in the blood) and high blood sugar levels.

Diabetes: Diabetes does not happen overnight. It is a disease that has been incubating and smoldering for years of bad eating habits. At the beginning, you may be one of the one hundred million people in the United States with what is known as metabolic syndrome: a constellation of conditions including high blood sugar, elevated blood pressure, increased waist circumference and abnormal cholesterol or triglycerides levels that put you at increased risk of developing diabetes, stroke and vascular disease. Blood vessels are especially susceptible to damage from sugar, leading to neuropathy, cardiovascular disease, blindness, kidney failure, and many other terrible complications.

In the early stages of diabetes, the beta cells in the pancreas work harder and harder to produce more insulin to deal with the excess glucose in the blood. Over time, the pancreas cannot keep up, causing a buildup of glucose and insulin in the blood. You have a condition of high blood sugar and hyperinsulinemia – and your cells are still not being nourished.

Type 2 diabetes is a disease of too much insulin - not too little. The disease manifests as too much sugar in the blood, but that's not the cause of the disease; the reason there is too much sugar in the blood is that the cells are resistant to absorbing the glucose.

This is no surprise: The more exposure to an item, the less impact it has; or the first notes of a siren may be bothersome, but if it continues, after a time it fades into the background. In the case of insulin, we become resistant to its effect because of the continued spikes of refined carbohydrates demanding persistently higher doses of insulin to be produced.

When you eat – especially refined carbohydrates, your blood sugar spikes, and the pancreas produces insulin in response to the spiked blood sugar. Insulin also communicates with the cells and stimulates the glut4 receptors in the cells to come to the surface of the cells to allow glucose to get through the cell wall. The message is we are getting glucose to use for energy now, store it, or use for energy later.

If you consume an overabundance of refined carbohydrates, your blood sugar level spikes rapidly and requires insulin to be produced quickly as well.  The cells get to the point where they resist letting the glucose in. This happens over years. The cells themselves no longer allow the glucose in, and glucose accumulates in the bloodstream, desensitizing the cells to insulin over time.

Treatment with insulin to reduce blood sugar is the opposite of what must be done! When taking exogenous insulin, eventually the pancreas simply shuts down and stops producing it on its own.

The problem with too much insulin in the blood is (1) the cells no longer respond to it (hyperinsulinemia), and (2) that condition triggers the liver to start converting sugar, specifically fructose, into fat.

This process – storing fat when you have too much glucose and burning fat when you do not have enough glucose – is how the body was designed to work.