In the fitness world everyone loves to throw around the words anabolic and catabolic. Anabolic meaning growth and catabolic meaning breakdown. “Looking pretty catabolic bro” has become a stinging insult in gyms somehow. Cute. What these gym junkies are really referring to is the idea of muscle anabolism versus catabolism, or growth versus breakdown. Now of course growth and breakdown can refer to any tissue type (skeletal muscle, adipose, nervous, connective). So in the context of the ever popularly sought after muscle growth versus fat loss formula, the “anabolic/catabolic teeter totter” must be considered.
What do I mean when I call it a “teeter totter”? Well your body has many, many hormones that are constantly signaling cells to either build up or break down all day, every day. This could mean building up glycogen stores in skeletal muscle for fueling your next strength workout. It could mean breaking down fat stores in adipocytes for energy production during your afternoon stroll. Or maybe increasing protein synthesis within myocytes for muscle repair and growth after a grueling yoga session. Again, these examples are in the context of changing body composition, which is what most people are interested in. So then the question remains….how do we go about controlling our anabolic and catabolic hormones for optimizing muscle gain AND maximizing fat loss?
Before I answer that directly, lets zoom out a bit and take a look at the “bigger picture”. One thing I’ve always loved about science is how it always leads us back to nature when we are searching for optimal health. It’s as if we were “designed” to be really good at surviving in our environment regardless of changing conditions……weird. Or maybe billions of years of trial and error has given us that gift. That’s beside the point, but to get back on topic, we can learn a lot by observing life in a more natural and primal state. If you’re a parent, babysitter, or just subject yourself to unnecessary torment, you’ve probably seen some of the Disney Nature movies such as African Cats. I mean look at those lions! They spend most of their day playing, sleeping, playing some more, sleeping again, eating what the woman folk drug in etc. Particularly the Alpha Lion! What a life! He pretty much lays around and chills until his female counter part brings him food, aka brings her children food, aka he gets first dibs because he’s the boss, aka he hits his kids to get the food, aka alpha lions beat their children. Now here and there he might have to go into a sympathetic “fight or flight” mode to fight off another Pride’s Alpha male, but for the most part he spends his days in a parasympathetic “rest and digest/feed and breed” mode. Doesn’t sound too bad to me! Could be worth incorporating “Lion Living” into your home….you know…..if you’re a dude….and “the man” of the house. Just saying.
So what does this have to do us human folk and balancing our muscle building and fat burning hormones?
Everything my dear lion cub. Everything.
You see through evolution, us human folk have developed survival mechanisms that are nothing short of astounding! The peripheral nervous system has a control system that directly influences the function of our internal bodily function almost completely unconsciously. This system, the autonomic nervous system (ANS) prepares our body for the activities immediately necessary for survival and/or, our health. It detects cues in our environment and within our body that indicate a need for action, whether that is to drive us to forage for food, heighten our senses to detect a possible threat, or focus blood flow to digestive organs to prepare the body for the meal to come. It does all of this through hormonal signaling.
Again getting back to what we all care about so much, muscle gain/fat loss, there are some key hormones to understand in order to maximize your fitness and health. Now it’s important to always keep in mind that hormones are not isolated in their function or role in the body. You can’t think of any one hormone as either “fat storing”, “fat releasing”, “muscle building”, or “muscle destroying”, as many hormones have a different effect on different tissues. For the sake of this article we will limit our focus to the following key players:
Insulin- is a peptide hormone secreted from beta cells in the pancreas to stimulate the uptake of nutrients into the cells. It lowers HSL (hormone sensitive lipase) which is our main fat releasing enzyme, while also raising LPL (lipo protein lipase) which is our main fat storing enzyme. However, what’s really spiffy, and perhaps unfortunate, is that insulin will actually lower LPL activity in muscle tissue and raise LPL activity in fat tissue. What does this mean? Lipo protein lipase is the enzyme that essentially “cuts” a triglyceride into its constituent glycerol molecule and three fatty acids. This allows the fatty acids to diffuse across cell membranes to be stored as fuel or burned for energy. So by lowering LPL activity in muscle tissue, insulin is actually preventing fatty acids from being stored or burned within muscle tissue, while simultaneously promoting fatty acids to be stored in fat cells and preventing it’s release. So as I said above, hormones are not “one trick molecules”. They’re actions can be different across the tissue types.
Now that all makes insulin sound great from a primal survival standpoint, but quite unenjoyable in our modern society of abundant food and protruding waist lines. It might even sound scary enough to abandon all ships to jump on the “low carb train”. Keto cakes anyone? But before you go running for the bulletproof coffee, keep in mind that insulin also triggers muscle cells to soak up amino acids while also directly stimulating cellular ribosomes to upregulate protein synthesis (bring on the muscle building). Now you might just want to put down the stick of butter you’ve been gnawing on for the past few sentences and start picking up the pure dextrose pixie sticks. You know….cause’ you gotta’ get them post workout carbs brah!
Catecholamines- are a class of amino acid based hormones that include dopamine, norepinephrine, and epinephrine. They are all derived from the amino acids L-Phenylalanine and L-Tyrosine and mediated through a multi-enzymatic reaction. The catecholamines ultimately are your fast responders to create the “fight or flight” reaction to immediate stressors. They heighten mental awareness and focus, raise blood sugar, stimulate fat release, increase heart rate and blood pressure, and increase blood flow to skeletal muscle.
Don’t be mistaken though, you don’t have to have a life threatening event occur to stimulate these potent fat burning, energy producing molecules! An anaerobic workout (sprinting, weights etc.) will stimulate their release as a coping mechanism to keep up with energy demands. In the hours after a meal their levels will increase in order to stimulate fat release and blood sugar rise to support energy requirements between feeding opportunities. This is precisely why I call it the “anabolic/catabolic teeter totter”. You eat and storage is promoted. You don’t eat and release is promoted. Checks and balances.
Cortisol- ahhhhh cortisol. How it has been attacked in recent years. Cortisol is our primary “stress hormone”. It is a steroid hormone (glucocorticoid) derived from the “mother molecule”, pregnenolone. Cortisol actually has its own natural bio-rhythm and is at its highest in the morning to promote wakefulness and energy, while being at its lowest in the evening to allow for restful sleep. Honestly I think the term “stress” has been over used in the health and fitness world, especially in regards to cortisol and the catecholamine hormones. However, it has stuck so I have created my own definition for stress: “stress- is the body’s necessity for mental acuity and physical work capacity.” Feel free to use that line on your next first, and only, date! You’re welcome!
Now cortisol gets a bad rap because it does trigger muscle tissue to be broken down into its amino acid building blocks for energy availability. However, cortisol also increases fat mobilization also for the sake of energy availability. You can think of it as a back-up adrenaline. Certainly long term stress can lead to overly heightened cortisol levels throughout the day which can cause excessive muscle breakdown, blood sugar rise, and even hinder other endocrine systems (thyroid, estrogens, androgens), but when controlled it is crucial for proper energy balance and influencing fat release.
So as we can see we need to take advantage of these hormone’s properties at key points of the day to maximize fat release, while minimizing muscle breakdown, or on the other end of the spectrum, maximize muscle growth and repair while minimizing fat storage. This is precisely why the traditional “bulking” and “cutting” phases are so flawed and also where many intra workout nutrition strategies are derived.
Although it’s true that insulin is most greatly influenced by carbohydrate intake, that doesn’t mean that our carb manipulation is the only way to “tip this totter” in our favor. In fact protein sources in some individuals can raise insulin levels just as much, if not more, than starchy foods. This is also why I included the catecholamines in this conversation. If you have always tended to be a wired, type A personality, chances are your genetics predispose you to spending more time in a heightened sympathetic state. Although it makes sense to take in carbohydrates after a strenuous anaerobic workout to replenish glycogen stores while insulin sensitivity is sky high, some individuals, due to stress hormone disturbances, might benefit more from having a carb heavy meal in the evening to qualm the stress response. On the flip side, if someone chooses to work out in the morning they may gravitate towards eating carbs with breakfast to fuel up before hitting the weights. However they must decide if the performance boost from the carb intake outweighs the potential performance boost they might get from having higher catecholamine levels.
If you spend more time in an anabolic state then you will gain weight over time. Vice versa if you spend the majority of your time in a catabolic state you will obviously lose weight. Now of course that doesn’t specify the type of weight being gained or lost (muscle, fat, water, glycogen). The true power to this is in using strategies to balance that teeter totter to being completely level on average. This is what makes losing fat and gaining muscle at the same time possible! This is what we call body recomposition!
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