Leptin - What is this mysterious hormone?
Leptin has often been a hormone that is overlooked by coaches in the health and fitness industry. I was first introduced to how the hormone works and its role with body fat and obesity by my coach/mentor Jeff Black. It made sense when dealing with most general population clients as a fitness coach. I often see clients who struggle to eat anything at all because they are never hungry. I also see those who cannot put food down and always feel hungry. Both of these situations deal directly with how much leptin the body is producing.
Typically, the more body fat you have, the more leptin your body will produce, which signals that the body is full and does not need more energy. The same goes for people who are lower in body fat, leptin will also be more moderate levels. When someone diet's body fat real low, this can produce some intense hunger cravings due to leptin being lower. This is why it makes it difficult to diet off body fat in most cases, due to most people not being able to resist the urge to eat food when they get hungry.
There are a few factors that come into play with leptin levels. As a coach, when asking my clients how tracking food is going, I typically get the response, "I got so busy I forgot to eat."
These long periods of fasting can wreak havoc on your leptin levels, which can leave you feeling like you will starve to death. This happens a lot to my clients, and then they get so hungry they don't care where they get their food from, they just eat whatever they can get their hands on. This is clearly not a good thing and will cause a plateau for a person trying to diet off body fat.
With that being said, I am not talking about those who follow an intermittent fasting diet. If this is the case for you, I recommend setting up reminders on your phone that will tell you to eat every 3 hours or whatever will fit into your own schedule. Carbohydrate re-feeds can have a positive response on leptin and fat loss. After a re-feed, it could take up to 48 hours for leptin levels to increase. This is why you will see a person who has been dieting low calories for weeks to drop body fat after a re-feed.
The hormone spike will have a direct impact on your metabolism, which can kick start fat loss. Keep in mind that if you decide to do planned re-feeds, you should keep your protein intake the same and keep fat intake at minimum for the re-feed day only. When I mean at minimum, I am referring to at least 20% of total caloric intake. The lower fat intake will not get in the way of your leptin response, which will be beneficial for the re-feed in general. You need to have a plan for your re-feed for this to work effectively, you cannot just order a pizza with ice cream and expect great results, it just doesn't work like that.
Sleep is also an essential factor when it comes to leptin levels. Research indicates that sleeping less than 8 hours per night over the long term can result in lower leptin concentrations, which can make dropping body fat harder due to the increased cravings.
How Leptin Works
Leptin is a hormone released from the fat cells and sends signals to the hypothalamus, which in turn helps the hormone regulate and alter long-term food intake and energy expenditure. The primary function of this hormone is to help the body maintain its weight. As I referred to in the paragraph above, the body does not trigger hunger responses when energy is not needed. Things can begin to shift as people diet their body fat off, causing the hormone level to lower naturally. This can really produce some considerable increases in appetite and food cravings, which is why so many people struggle to diet their body fat off. Imagine a person who sits around 30% body fat tries to diet down to 15% body fat. At 30% body fat, that individual is going to have more leptin in the blood, which may trigger some crazy hunger pains when they begin to diet the fat off. This is all due to the hormone lowering as their body fat lowers, and is a normal response. There is also something called leptin resistance, which we will dive deeper into in part 2. The basis of this is when a person who is obese has leptin levels too high in their bloodstream, which can lead to insensitivity. When this occurs, the brain no longer signals the feeling of satiety, which can be troublesome for the individual as they will continue to eat and add body fat, which will make leptin levels continue to rise. You can see the trend with this, right? It can be a long road for an obese individual who wants to diet their body fat off, but one that is filled with newfound will power and reward. In part 2, I plan to dive a little deeper into leptin resistance, and if leptin resistance can be reversed. I will also expound upon a condition known as congenital leptin deficiency, which keeps the body from producing leptin.