digest
Intermittent fasting, I've seen your requests and read your comments, so here we go. I'm dying to talk to you about this. I eat for eight hours and I fast for 16. I can feel the difference. Before we get into the pros and cons and whether you should do it, let's talk about what intermittent fasting actually is.
Human fasting is not a new concept by any means. Humans have been doing it for millennia. Intermittent fasting is just a rebranding of something we have already been doing. Our bodies enter a fasting state every time we're asleep. Some people do intermittent fasting and don't even know it. I mean, there are plenty of times where I had a stressful rotation in medical school or a difficult job in the hospital where I didn't have time to eat breakfast. That's a form of intermittent fasting, and our bodies are totally capable of handling this.
I know what you're thinking: I don't want to starve myself for health benefits. Intermittent fasting is not starving. When you're fasting, your body is using stored nutrients and stored energy forms in order to keep functioning. When you're starving, you've run out of those energy sources and are breaking down vital tissues, like organs, to get that same energy.
There are many different ways to go about these diets, and that not only makes it confusing for you but also makes it very difficult to do research on it and find out how effective it truly is. If there are multiple ways to do it, we have to be able to test each one of those ways. The 16:8 diet means not eating during 16 hours of the day. Alternate-day fasting means you eat one day and fast the other day. The 5:2 approach means two days of the week you're fasting. There's no hard and fast rule saying this is the correct way of doing it.
You may be wondering how intermittent fasting is beneficial to you. There have been a lot of proposed health benefits. Many of them have been proven within animal studies or lab models, which is not the same thing as being proven in a human model, but they are very promising. Those benefits include increased mental sharpness, a favorable hormonal profile, weight loss, decreases of inflammation within the body, and decreases of certain diseases within the body.
How can intermittent fasting help you lose weight? You have an increase in growth hormone and a decrease in insulin, and that alone will help you lose weight. Next, because you're skipping meals or even going days without eating meals, it's very likely that when you look throughout the week, you'll be eating fewer calories. Our thinking is that during eight hours you'll eat less than you would if you were eating during the full day.
In terms of health benefits, we know that chronic stress is not good for the body. The body is just not meant to be chronically stressed out. It's not meant to have a high heart rate or high blood pressure. Intermittent fasting is really a form of acute, short-term, mild stress, and this type of acute, short-term stress is really good for the body. What can we use as a metaphor here? Let's take exercise. Exercise is a form of acute mild stress. What happens after exercise? We have benefits for the brain, we have benefits for weight loss, and we have benefits for disease prevention. Similarly, when you stress your body through intermittent fasting, there are some benefits: more autophagy, which is the removal of cellular waste; more production of neurotrophic factors, which protect your brain; and a favorable hormonal profile with increases in human growth hormone and norepinephrine.
Let's talk about some of the shortcomings of intermittent fasting. Primarily, there's not enough guidance on what you should eat. We don't know how many calories, and we don't know what foods to eat on the days or times that you are actually eating. Second, we don't know which form of intermittent fasting is best. Third, there are side effects when you are fasting that people do experience, such as headaches, mental fog, and heartburn. These things do exist, so it's not totally benign. Fourth, we don't know the consequences of following an intermittent fasting diet long term. Most, if not all, of these studies are done in the short term. If you are eating a very unhealthy diet and then make a change, you're definitely going to see a benefit, but does this benefit still hold up one, two, three, or ten years down the line? We don't know that yet. And fifth, it's not easy for everybody to fight off cravings on fasting days.
All right, my final take on intermittent fasting is that I think it's a great concept with some really promising medical research behind it. I think that if you can skip a meal, you can skip a breakfast here and there, and you're going to see some benefits. Does that mean you should go on a very rigid diet where you're doing the 5:2 or the 16:8? I don't think we should make this a religious, rigorous part of our everyday life, because we don't know the long-term consequences of it. But in a society that's prone to overeating, a fasting day won't hurt and will probably help. As always, stay happy and healthy.
So here we go: intermittent fasting, kind of an intermittent... yeah, it was like borderline. Our bodies have adapted to this sort of fasting period. Throughout the millennia, many people have been doing this already, and our bodies are totally capable of, and have adapted to, not being filled with food 24 hours a day. Why are you laughing? Creating more mitochondria, which is the energy-making machinery of the cell, the energy center of the cell.