How Insulin Drives Weight Gain
These are the notes from last night’s video in the 28 Day Challenge. You can join us in the 28 Day Challenge FaceBook Group here, get our FREE 28 Day Ketogenic Meal Plan here, and pick up our recipe and instructional books here.
So how exactly does insulin drive weight gain? The answer is a bit technical but incredibly fascinating. I think once we are done with these next 2 days, you will have a much better idea of exactly how your body decides what to store and what to use for fuel and you will be able to make much smarter decisions about exactly what you should be eating.
It used to be thought that your fat stores were a kind of “energy bank”. That your body was packing away those pounds in a kind of long term storage for the day when you were starving or dieting or exercising or whatever and needed the extra energy. We now know that this isn’t true. Energy from your fat stores are constantly flowing in and out of your blood stream to be used as fuel and if you don’t need it, it goes right back into your fat cells. The reason we have been told that energy from carbs, or glucose, is the body’s preferred source of energy is because your body will use energy from glucose first because it wants to keep your blood sugar at a constant level. Your body uses this energy first before it uses the fat. And now we start to see the root of our obesity issue.
Imagine you eat a Standard American meal consisting of a roughly equal mix of dietary fat, protein and carbs, the 3 macronutrients. You body quickly goes about the business of digesting and breaking down this food into a form it can use to perform all the metabolic processes it needs to perform. Protein is broken down into amino acids which your body uses as many of as it can but if you eat too many these amino acids undergo a process called gluconeogenesis at which point your body treats them like they would a carb. The fat is broken down into fatty acids and while a certain amount is quickly used for the metabolic processes that require fatty acids, it is mostly just sat aside into fat cells while the body deals with the carbs. The carbs you eat is where this process really begins to take shape and your understanding of what happens when you eat will begin to get clearer.
Carbs are broken down by the liver into glucose which raises your blood sugar level. Your body doesn’t like your blood sugar level to be too high so it devotes most of its energy to normalizing your blood sugar. The first thing it does is to take this glucose to every cell in the body and give it a chance to use it for fuel. However, if you ate too many carbs for you to use as fuel right then, your body still has to get that sugar out of the blood stream and to do that, it needs help from the real villain in our weight loss story, the hormone insulin.
Insulin does several things in the body but its most critical role is it controls your blood sugar levels. You might be familiar with insulin if you or someone you know has Type 1 Diabetes or has insulin dependant Type 2 Diabetes. In order to deal with the increase in blood sugar, insulin is secreted by the pancreas (or injected) and signals the cells in the body to increase the rate at which they pull glucose out of the bloodstream. Some cells burn the glucose immediately and some store it for later use. Liver and muscle cells store it in the form of glycogen for later use and fat cells store it as fat for later use. As your blood sugar decreases, the insulin levels decrease and your body goes back to pulling energy in and out of fat cells for all the metabolic processes it needs to power. This is why you can sleep 8 hours through the night and not wake up with hunger at midnight because your body is using that stored fat as fuel.
Ok, so if fat is flowing constantly in and out of fat cells, why does it seem like more is going in than going out? To answer that we have to look more closely at how the body stores fat. There are 2 different types of fat your body deals with. The first is fatty acids, this type of fat flows easily in and out of cells and is what your body burns for fuel. The second type is triglycerides and this is the fat your body stores and is composed of 3 fatty acids linked to a glycerol molecule. Imagine the capital letter E where the vertical stroke is a glycerol molecule and the 3 horizontal times are the 3 fatty acid molecules.
The reason the body burns fatty acids for fuel is because the fatty acids are small enough to pass through the membranes surrounding the fat cells so the body has easy access to it. Once a fatty acid is linked to 2 other fatty acid molecules and a glycerol molecule, it’s too big to pass through that cell membrane and just stays put. Think of triglyceride has a piece of furniture that is too big to moved from one room to another in your house and must be deconstructed while in the room and brought out piece by piece to get to the next room. So once a fatty acid passes into your fat cell and gets converted to a triglyceride, it’s pretty much stuck there until deconstructed and your body won’t typically start breaking down triglycerides into fatty acids for fuel if there is a lot of other things your body can use for fuel instead, namely glucose.
So here’s the crux of the issue. Anything that pushes fatty acids and glucose into cells where they will be converted into triglycerides makes you fatter, anything that speeds up the break down of triglycerides into its component parts and lets it out of the fat cell makes you leaner.
This is why people tend to slowly gain weight over the years because more and more fat and sugar gets converted into these triglycerides and as long as you give your body a continuous stream of glucose, your body has no reason to break down those triglycerides for fuel.
Tomorrow we will look at exactly what controls this metabolic process so we can reverse it.