Focusing on Hormonal Response: Missing the Forest for the Trees
Physiology is a tricky thing. As soon as we think we have a piece nailed down, we forget how it interacts with the greater whole. The body is a complex organism of interrelated, integrated systems, with multiple and redundant feedback mechanisms. Often times, when researchers examine a piece of this puzzle and pass down their findings to the students and practitioners, the big picture is lost in the details. This is often the case with regards to how the hormones in the body acutely respond to dieting and training. A while back, I wrote about the misconceptions related to hormonal release from training and the common pitfall of trying to design programs to spike GH and testosterone (Part 1, Part 2). Today, I’m going to discuss GH again, but from the dieting angle along with insulin, and I’ll also touch briefly on cortisol. I will get a little technical, but I’ll pay plenty attention to the big picture instead of mucking around in the details since that’s where the mistakes are made in the first place.
Very often, certain dieting patterns, macro nutrient combinations, food combinations, and food timing recommendations are made in an effort to manipulate Growth Hormone. One of the actions of GH is that it promotes fat burning. However, often it is seen as the only mechanism of fat burning, and the big picture is missed. The catecholamines (epinephrine/nor-epinephrine), leptin, and a few other hormones are also at play here and have a very significant effect on fat loss. But much more importantly, a caloric deficit is the determining factor to whether or not you will burn fat. Hormones are simply the tools the body uses in a deficit to mobilize and burn fat, they are not a separate process. Seriously read that one again.
Let me explain a little bit. Being in a negative energy balance (dieting), means the body is looking for energy to replace what is below its baseline energy expenditure. To do this, it releases hormones to liberate stored tissue, including body fat. One of these hormones is GH, and it is lipolytic (burns fat). But, the reason hormones are released is because you are in a deficit in the first place. The body won't try to burn fat for energy if you are taking in enough calories in the first place. Once you create a deficit, the body liberates fat stores (by releasing fat burning hormones like GH and others) to replace that deficit and fat storage decreases (by decreasing insulin and other hormones).
I have even seen some coaches and bodybuilders recommend not eating carbs post workout because it blunts the GH response after exercise. The benefits carbohydrate provides post workout greatly outweighs its blunting effect on GH. I wonder what these coaches think GH is doing all the other times in the day when you aren't eating (which is like 20 hours out of the day)? Don’t they realize that GH is working for you if you’re in a deficit anytime you aren’t eating? Why focus on cutting carbs from the period after a workout when eating carbs is beneficial, instead of the other times of the day when carbs aren’t so useful? Sometimes when you focus on the magnifying glass details, you miss the big picture.
Energy balance/thermodynamics and the hormonal methods of fat loss are not two separate things. Paying attention to calorie balance and hormone response simultaneously doesn't make a whole lot of sense. These two things can’t be operating in conflict with one another. Hormones are used to meet the energy balance. If you are in a surplus, insulin (among others) is one of the drivers to store energy, and if you are in a deficit, GH (among others) is one of the drivers to use stored energy. The focus should be on the surplus and the deficit, not the hormones. GH and insulin are just how the deficit works. Remember, the body has methods of storing and burning fat beyond GH and insulin anyway. Remember that whole complex, interrelated, integrated, redundant feedback thingy I said in the first paragraph?
I am actually oversimplifying things here. In reality, storage hormones and fat burning hormones are always simultaneously at play. In addition, they have dose dependent responses to food intake. When you are in a deficit, the emphasis is just pushed more towards releasing stored tissue for energy, and when you are in a surplus, the emphasis is pushed more towards storing ingested calories. It's not an on and off switch, truly nothing is in the body is. A much better characterization is that it is a sliding scale. Even in the very short term, you actually store fat at pretty much each meal. Conversely, you burn fat between meals and when you sleep. The net balance of how much you store and how much you burn determines whether or not you lose weight and fat. This is dictated by energy balance: either deficit or surplus. The hormones are just how the body accomplishes the task.
So it’s time to change our thinking. So what if you store more fat at a specific meal? So what if you aren’t burning fat while you’re doing cardio? What matters is net fat loss over the long term. GH release is not a determining factor of net fat loss. Yes, while GH is released fat is mobilized, but if you aren't in a caloric deficit it will be restored later in the day. The same is true of insulin. When you eat a meal and release insulin, some of the calories are stored as fat. If those calories that were stored aren’t needed, they will stay stored. But, if they are needed (even 10 minutes later), they will be released and used for energy. This is exactly what happens when you are in a caloric deficit. This common misunderstanding has lead to a number of misguided hormone manipulating strategies in bodybuilding:
Whether it is 9pm, post workout, or first thing in the morning, you will have a hormonal response to food that is dose dependent based on food intake. If you have 2500 calories for the day, when you eat a portion of those 2500 calories, there will likely be more storage than release, when you aren't eating a portion of the 2500 calories there will likely be more release than storage. Insulin and GH are not on and off switches. You can store fat in the presence of GH, and you can burn fat in the presence of insulin. Again, remember they are sliding scales. It is a rolling process of metabolic peaks and valleys. Or, like a bank account.
Carb cut offs, or avoiding post workout carbs is akin to looking at isolated transactions over the course of a bank statement. Sure, on December 1st you might have only had $4 in your bank account because you just paid your rent. But, on December 15th you had $600 because you just got paid. To determine whether you are gaining or losing money you have to look at the annual statement, not just the transactions that happened on a specific date.
The body is constantly making transactions, both adding and subtracting. The hormones are just how it is happening; it is the end result that matters.
Too often people focus on how much fat is being burned immediately during their cardio session, or immediately during their meal. Who cares if you store fat at 5pm if you are burning it the rest of the day? The only way to burn maximal fat, all day long is to not eat at all, and to be honest I’m surprised nobody has suggested this yet considering how grossly these systems are misunderstood.
It is high time we stop labeling hormones as either “good” or “bad” when they are so much more complicated than that. Another example is cortisol; it is often labeled as a catabolic hormone that eats muscle tissue. There are even supplements designed to minimize cortisol. However, cortisol is much more dynamic than that. Cortisol is elevated the most when you lift weights. How much it is elevated is an indicator of how much stress you put on your body. So does that mean we should never train hard to avoid elevating cortisol too much? Of course not, since we know hard training causes adaptation and growth. There is a bigger picture at work here. Telling someone not to eat carbs post workout because it blunts GH response, is like telling someone not to lift weights because it increases cortisol.