 Hey everybody, Dr. O here and this video we're going to talk about the fed versus fasted state. Let's just get some of the things out of the way. The fed state, the key thing to note, its other name is the absorptive state because it's when you're absorbing nutrients that you just ate. The fed state is usually going to be in the window of up to four hours after you eat and the fed state is dominated by insulin. The fasted state is also known as the post absorptive state. It's going to be anytime when you have an ate in at least a few hours and it's going to be dominated by glucagon. Let's go ahead and take a look at the fed state first and then the fasted state. We're going to look at what's happening at the liver, at the muscles and at the fat tissue. Here, let's just start after you eat. There's an influx of nutrients coming in unless you're on a very low carb diet that's going to involve the absorption of a lot of glucose and as your blood glucose rises that's going to stimulate insulin. Insulin's primary job is to lower blood glucose but it's actually an anabolic storage hormone. As you're going to see it plays a role in fat storage and amino acid storage and synthesis as well. Let's start at the liver. At the liver, the key thing that's going to happen is this excess glucose that's not being used for fuel elsewhere will be stored as glycogen. The liver turns glucose into glycogen. That's the storage form of carbohydrate in the human body. You also see that you can certainly see some extra amino acids being converted into ketones as well or ketone bodies if you're on a higher protein diet potentially. Muscle cells, same thing. They're going to take in that glucose and they're going to use some for fuel and store some as glycogen. Insulin is also going to lead in muscle cells to absorb amino acids and use them to build muscle as well. Then adipose cells, your fat cells, they're going to take in excess energy and store it as fat. That's what's happening during the fed state. After you've eaten, your body is going to use what it needs in the moment but primarily it's going to be storing what you just consumed. That's the fed state. Now we have the post-absorptive or fasted state. Notice there's nothing coming in through the intestines now because you haven't eaten in let's say four or more hours. Maybe if you think about it, it's called breakfast for a reason. If you had supper at 6 p.m. and you wake up at 7 and eat, you've gone 13 hours without eating. So that would be the fasted state. So as blood glucose levels drop, insulin levels should also drop and glucagon should take over. Glucagon's primary job is to keep your blood glucose up. So at the liver cell, you're going to see this glycogen that you've stored is going to be turned back into glucose. And then also we can be burning some ketones for fuel if needed. Muscle cells, same thing. The glycogen your muscle cells took up are now going to be turned back into glucose and used for fuel. And you can also be, if you need to increase blood glucose levels and you don't have carbohydrates, we'll see what that can do. But you can also break down proteins and use them for fuel as well. And then thirdly, we have the adipose cells. They stored the excess calories, excess energies as fat. Now they're going to be releasing that fat. So it can be oxidized using beta oxidation to generate ATP or can be used to produce ketones. So that is the fed versus fasted state. What's happening in your body, whether it depends on whether you've recently eaten or you haven't. But in the end, every cell needs fuel every second. If we don't keep our mitochondria churning out ATP, we don't have a metabolism. And if you don't have a metabolism, you don't have life. So all right, I hope this helps. Have a wonderful day. Be blessed.