Leptin is a protein that is made in your fat cells and is transported to your brain through your bloodstream. Leptin tells your hypothalamus (a specific area of the brain) that you have enough energy. Leptin is kind of like your food accountant, it tells the brain you've eaten enough food and stored enough energy to engage in activity. Just like a good accountant, leptin says, "Your cash/energy flow is positive and you've got enough to cover all your essential expenses, so feel free to go spend some money/energy on other things." Most important of all: You are not in starvation mode when leptin is talking to your hypothalamus. What is starvation mode you ask? Let's say you're on one of those extreme "juice cleanse" diets. Leptin is not being sent to your brain and, as a result, your brain senses starvation and goes into survival mode. Your brain and body's primary goal right now is to get you fed. So the brain sends a signal to your vagus nerve (the longest cranial nerve in the body that stretches all the way to your abdomen) and that causes the feeling of hunger. Your brain also sends a signal to your thyroid that slows your metabolic rate. In starvation mode, your body is doing everything it can to extend the energy stores you have until you feed it again. So here you are, trying to drop a few pounds, and your body is working in overdrive to hold onto fat until you give it some food. Seems a bit inefficient, no?
Here's another way your body is working against you and your juice cleanse: Once leptin gets to the hypothalamus it sets off these "leptin-responsive" neurons in your brain. These neurons feed directly into the dopamine system, which controls the brain's reward and pleasure center. The lower your dopamine level, the more rewarding food becomes. The higher your dopamine level, the less rewarding food becomes. THIS IS NOT ABOUT WILLPOWER PEOPLE. You are biologically programmed to properly feed your body. So if you can't starve yourself to lose weight, what can you do? Eat the right foods. Eat the foods that keep your leptin and dopamine levels high. I promise to help us all figure out what those are. I just can't do it in the space of this post. The good news is that the ones I know about taste really, really good -- and are SO much better than endless glasses of brownish green juice!
Now, there's a wrench in this explanation that I'm sure you guys are bound to catch. Don't obese people have lots of leptin if it's generated by fat cells? Yes, an obese person does have high leptin levels, unfortunately, there is something blocking the leptin from getting to the hypothalamus. There are particular foods that make this happen. I'll get into this in more detail later as well. But here's something to get you thinking: Ever notice how certain foods never make you full? Like that time you sat down with a bag of potato chips and ate the whole thing? You were like, holy crap, where did that bag of potato chips just go? Those potato chips were not generating any leptin, but they did give your body some carbohydrates which it is going to store until you give it what it really wants.
The key to controlling leptin is knowing which foods allow it to function normally and which foods block it from signaling your brain. It probably doesn't come as a surprise to you that many of the most well-known "bad" foods are not conducive to leptin functionality (e.g., chips, soda, cupcakes), but there are also a lot of other foods that might surprise you. What also may surprise you is the food that is conducive to leptin functionality: fat. Heart advocates, please indulge me, we have been very misled about fat. When you eat the right fat, it's not going to clog your arteries, but we'll get into the different types of fat and what your body does with them in another post.
The main thing to take away about leptin is that the right foods make you full (and happy!) and don't cause you to gain weight. Leptin does all your accounting for you (no calorie counting!) if you eat the right foods. Furthermore, if you are already full, eating a bag of potato chips is not appealing to you. If you eat the right food, you will feel satisfied and your leptin and dopamine levels will be high. If you eat the right food, you will be less hungry and more happy. Sounds like a win-win, right?
Dr. Lustig has a lot to say about leptin, you can read more about this amazing protein here, here, and here.
No comments:
Post a Comment