 Hey everybody, Dr. O here. In this video, I'm going to cover the science behind the number one reason poor sleep makes us gain weight. Simply put, you overeat when you are underslept. So here you see my before and after picture. I weighed 414 pounds in the picture on the left. I was able to lose 49 pounds in 10 weeks, 101.2 pounds in 6 months and 165 pounds in one year. And people are shocked when I tell them that one of the biggest things I did was focusing on sleep. It completely changed who I was. Let's go ahead and look at how this lack of sleep led me to overeat and is probably leading you to overeat as well. So how does your body make you eat more or at least want to eat more when you haven't been sleeping well? It's because poor sleep scrambles your hunger hormones. So let's look at the two key ones here. And they are leptin and ghrelin. Don't worry, there won't be a test, but leptin and ghrelin are the two key hormones that control how hungry you are. So leptin tells you that you're full. Leptin is a hormone released by your body fat that tells your brain how much stored energy you have or at least it should. So if you have a lot of leptin levels, your brain should get the message that you're full and it should make you eat less. It also should make you move more. It's pretty cool how it does that as well. But here's the problem. A single night of short sleep decreases leptin levels by almost 20%, about 18%. And it also decreases leptin sensitivity by 30%. So that means that if you didn't sleep well last night, your leptin levels are almost 20% lower and the leptin you do have is 30% less effective. So instead of getting the message that you're full, your body's getting the message that you are hungry. So low leptin levels are a key reason that you're hungry if you haven't slept well. Number two is grayling. So grayling is a hunger hormone. Grayling is a hormone released by your stomach, especially when it's empty that tells your brain that you should be eating, that you should be filling your stomach. So again, a single night of short sleep increases grayling by almost 30%. So your leptin levels are 20% lower and 30% less sensitive or less effective. Your grayling levels are almost 30% higher. Both of these hormonal messages are telling your body that you need to eat. Your body is literally screaming for food. So let's look at the data though. Let's look at how big of a deal this is. So what does the science say? Effects of sleep restriction on metabolism-related parameters in healthy adults, a comprehensive review and meta-analysis of randomized controlled trials. So this study found that if people weren't sleeping well, they were consuming 252.8 more calories per day. That would be 92,272 calories per year. That's more than 26 pounds of fat. But this next study is even worse. The effects of partial sleep deprivation on energy balance, a systematic review and meta-analysis. This study found that if you're sleep deprived, your energy intake increased by 385 calories per day. That's 140,525 calories per year, the equivalent of 40 pounds of body fat. This same study though also looked at sleep extension. So if someone's supposed to be sleeping seven to nine hours and they're sleeping five hours, they're eating 385 more calories than they should. But what if you take someone that is sleeping, let's say seven hours and you get them sleeping eight hours? So sleep extension reduced calorie intake by 156 calories per day. So if you take 385 calories from eating more of your poorly sleeping and you add 156 calories that you're now eating less because you've extended your sleep and you're sleeping better. That's a 541 calorie difference. That's 197,465 calories per year and that's the equivalent of over 56 pounds of fat. So what's the key takeaway here? A lack of sleep could be the main reason that you're eating too many calories. Look at these numbers. They're undeniable. So what's our action steps? We haven't talked about solutions yet, but if a lack of sleep is your problem, sleep is going to be the solution and I'll be teaching you over a hundred tips that can help you get better sleep along the way in this course. So take this seriously and I hope this helps. Have a wonderful day. Be blessed.