We’ve all cursed our hormones at one point or another, right? But do you know what hormones are and what they do? Do you understand the role your hormones play in your ability to lose body fat and maintain a lean weight?
What is a hormone anyway?
A hormone is a substance produced by one gland or organ of the body that then travels through the bloodstream to affect your cells, tissues and organs. There are hundreds of them at work in your body, bathing your cells in a hormone cocktail, and interacting with one another’s functions. Your body’s cells have receptors, and those receptors respond to specific hormones. The receptors work like locks on a door—the hormone that fits into the lock opens the door.
Almost like a team within your body, led by your brain. Most are produced by your endocrine system, whose main goal is to make sure your body has just the right amount of each hormone so your body can function properly. Some are produced in organs like your stomach and some are made by your fat tissue itself.
Your hormones have many roles, but one of the essential functions of hormones is to control and organize any and every body function you can imagine, like regulating growth, sexual development, the reproductive cycle, sleep, hair growth, hunger, and the production of red blood cells. All to keep your body’s systems operating within safe, healthy parameters and maintaining balance (or homeostasis). Think of them like a communication superhighway, passing messages back and forth throughout your body, telling your cells and organs and tissues what to do (or not do).
But, what do hormones have to do with your weight, you ask? A lot actually.
You’ve heard the term metabolism. It’s the process that establishes the rate at which we burn our calories, and ultimately, how quickly we gain weight or lose it. There are several key hormones involved in metabolism that, among other things:
- tell your body what do to with the energy that you give it by eating, whether that’s to burn it as fuel or store it for later;
- tell your body to increase or decrease fat stores;
- tell your body you’re hungry or full;
- tell your body to liberate energy to power your workout.
Because they play such a key role, it’s important for you to understand some basics about nine hormones involved in metabolism and your body’s regulation of stored energy (also known as the fat you carry). The information here is just the bare bones, and by no means a complete explanation. That would take me several pages! But it should be enough to help you understand just how much your hormones will influence your ability to lose fat and keep it off, as well as look and feel your best.
Adrenaline, also known as epinephrine, is part of the trio of hormones that kick in when your body experiences a physical or emotional stressor (“fight or flight response”). It acts to increase your heart rate, relax the muscles in your stomach and intestines, and increase blood flow to those organs. It also signals the release of cortisol, testosterone and human growth hormone—all of which have other functions to help your body deal with the stressor.
Cortisol is another of the hormones that are part of your stress response. It can be your best friend or worst enemy when it comes to fat burning. If cortisol is released when insulin is high and testosterone and growth hormone is low (i.e., you’re laying on the couch stuffing your face with chips and popcorn and something happens to cause stress), cortisol will be your enemy, driving fat storage and burning of muscle tissue. However, if cortisol is released with large amounts of growth hormone and testosterone (i.e., after a good strength workout or sprints), cortisol is a BFF, blocking the burning of muscle tissue and enhancing the burning of stored body fat for energy. Cortisol plays many roles, including:
- working with insulin to maintain constant blood sugar levels
- reducing inflammation
- signaling your body to stop producing “flight or flight” hormones once the stressor has passed, and to resume digestion
- telling your body which fat, protein or carbs to burn and when to burn them, depending on what kind of stressor you face
- taking fat from healthier areas, like your butt and hips, and moving it to your abdomen, which has more cortisol receptors.
Ghrelin is called the stomach-growl hormone. Even its pronunciation sounds like a growl. Ghrelin affects hunger from hour to hour, while leptin affects it from day to day. In addition to signaling your body to eat, ghrelin also helps your pituitary gland release growth hormone. And your body actually requires ghrelin to enable you to move effectively through all phases of sleep. So, it’s a pretty important hormone. When your body is losing body fat, the stomach is triggered to make more ghrelin, in turn triggering the desire to eat, which can make it difficult to keep weight off.
Insulin acts on virtually all of the cells in your body, controlling or influencing energy storage, cell growth and repair, reproductive function and, most importantly, blood sugar levels. You need what insulin does so that your cells have the building blocks they need to produce energy. One of insulin’s functions is to “unlock” a one-way door into your cells so they can use or store nutrients. It also pulls glucose out of your blood stream and moves it into storage to bring your blood sugar levels back into a normal range. These are good things.
But high insulin levels can work against you. Once your short-term storage tanks (liver and muscle tissue) are full, higher levels of circulating insulin tell your body that it has plenty of energy in short-term reserve so everything else needs to go into long-term storage (i.e., your fat cells). And when your body is in long-term storage mode, your ability to release fat and burn it for energy is completely blocked. Guess what foods make the most impact on insulin levels? Yep, it’s carbohydrates (starches, sweets, processed foods).
Glucagon is insulin’s alter ego. If insulin makes you store fat, then glucagon helps burn it. Glucagon works in the liver to help it regulate both sugar and fat usage. The insulin/glucagon ratio is a major determinant of whether you burn or store fat. In general, starches/sugar secrete insulin, while protein stimulates glucagon, so adjusting the protein/carb balance favors fat burning.
Leptin is the body’s fuel gauge. It’s secreted primarily in fat cells, as well as your stomach, heart, placenta and skeletal muscle. Leptin tells your brain how much body fat you have stored and regulates the use of what you take in and what you burn to keep body fat levels in balance—not to fat and not too lean. It has to work with thyroid hormone, cortisol and insulin to help your body figure out how hungry it is, how fast it will burn off the food you eat and if it will hang on to or tap into longer-term fat stores and reduce them. People who become leptin resistant will eat and eat as if they are starving. This is why some people become morbidly obese; their bodies never receive the message to stop eating and start burning.
In men, testosterone is produced in the testes. In women, it’s produced in small amounts in the ovaries and adrenal glands, which is also the source of DHEA for women. Testosterone and DHEA are androgens, which are anabolic (building) hormones. Men produce up to 10 times more testosterone than women, and that’s why they are able to build so much more muscle than women can (not fair, I know!). In both men and women, testosterone helps increase lean muscle mass (yay!) and strength, boosts libido (double yay!) and improves energy. DHEA may help prevent breast cancer, cardiovascular disease, impaired memory and brain function as well as osteoporosis. It may even help us live longer. Together, DHEA and testosterone play a fundamental role in the growth and repair of tissue.
8: Thyroid hormones
There are actually three thyroid hormones: T3, T4 and reverse T3. T3 is the active thyroid hormone. T4 and reverse T3 are “precursor” hormones that are used to produce T3. These hormones are primarily responsible for, among other things, stabilizing your metabolism, your resting metabolic rate (RMR), and your heart rate, breathing rate and body temperature. They also helps control overall growth, fertility, memory and mood. It takes cues from other hormones (like leptin) to maintain weight set point, which is the number on the scale your weight normally hovers around, give or take a few pounds.
9: Human Growth Hormone (HGH)
Human Growth Hormone (GH). GH is one of the most influential anabolic (building) hormones we have. In the right doses, it’s great stuff because plays a huge role in the growth of bone and other body tissue, while also enhancing your immune system. One very important role GH plays is helping you tap into your fat stores because it activates a process called lipolysis, which is the breakdown of fats and other lipids to release fatty acids. Fat cells have growth hormone receptors that trigger your cells to break down and burn your triglycerides. It also discourages your fat cells from absorbing or holding on to any fat floating around in your blood stream. GH also increases muscle mass by helping your body absorb amino acids, synthesize them into muscle, and then prevents the muscle from breaking down—all of which raise your resting metabolic rate (RMR) and give you more power for your workouts.
Growth hormone and testosterone work best together—meaning that each is very potent individually, but when they are present together, the impact is more prominent and beneficial for us. Women secrete GH more often than men do, and that could be the reason why women can build strength and muscle since, as I just explained, they have much lower levels of testosterone than men do.
We muck up the system
Hormones are not “bad” or “good” in the right amount. But things get really ugly when you have too much or not enough of any given hormone.
Your body interacts with millions of external variables every day. Like the contents of your meal, the time of day, the intensity of your workout, how stressed you’re feeling, how well you slept, and your energy needs at the moment. In response, your endocrine system releases hormones to help maintain homeostasis: balancing blood sugar, helping you drift off to sleep, burning fat, building muscle, signaling hunger or fullness, etc.
Sometimes those external variables shoot way off the charts, and your hormones don’t know which way is up. Our bodies can’t work the way they’re supposed to if our hormones are out of whack. Any disruption could send one hormone into overdrive and another into hibernation mode. And when the normal function of one gets thrown off, that imbalance creates another and another and another like ripples in a lake.
Your hormones try to help your body regain balance, but in the face of the foods we choose to eat or the lifestyle choices we make, they begin to over-react and over-compensate. And it just keeps getting worse unless you do something to try to correct it.