NOTE: The following post is intended as a high-level view of fat oxidation as a key piece of a healthy body. For a deeper dive into the topic, check out my Your Health, Reprogrammed series on Excess Fat Accumulation.
The excess accumulation of fat is one of the defining features of a metabolically unhealthy body. When fat is stored in excess, it can become a burden on cells and tissues throughout the body, playing a role in diverse pathways of poor health and disease progression.
Therefore, it makes sense that to become healthier, most individuals could benefit from burning more fat.
Simple, right?
Well, no, actually. As always, the (patho)physiology goes much deeper than the normal headlines with tips and tricks to burn more fat.
That being said, there is truth to these ideas if we look closely enough. That’s our goal here: to cut straight to the useful science that we can apply in our lives to make us healthier individuals.
Why is it useful to think about burning more fat?
To kick things off, I have to clarify what it actually means to “burn fat.”
When we talk colloquially about “burning fat” we are speaking to the process that is fatty acid oxidation: a process of taking the fat within the body, converting it to ATP (the body’s useable form of energy), and releasing what’s left as carbon dioxide (which we exhale). Fat is utilized as a fuel source within the cell at the site of the mitochondria, during which the molecule is broken down into individual carbon and hydrogen atoms which are then used to synthesize ATP so that the cell can do work.
It’s also worth noting that cells are capable of utilizing different biomolecules as fuel sources, although the two most significant biomolecules for our purposes are fatty acids and sugars (most notably, glucose).
Given this brief intro into the oxidation of fatty acids, here’s what you need to know to be able to make healthier decisions:
In a metabolically healthy individual, most cells are programmed to utilize fatty acids as a fuel source under fasted and resting conditions. That is, a metabolically healthy individual is going to spend most of the time running on fatty acids as a fuel source.
This changes under different conditions, most notably when that individual eats a meal containing carbohydrates or when that individual exercises at higher intensities. When this happens, the body will shift over to utilizing glucose as a fuel source.
This metabolic flexibility is a useful design because it enables us to run long-term on fat (an efficient fuel source due to its dense energy and relatively fewer by-products), and to shift to utilizing carbohydrates when necessary.
What happens, though, when an individual becomes metabolically unhealthy and loses the ability to efficiently utilize fats as a fuel source?
- The systems supporting that individual’s body would have unstable energy due to the dependency on the ingestion of glucose.
- That individual’s body would be more likely to store energy as fat, resulting in the excess accumulation of fat throughout the body.
- That individual would likely suffer from dyslipidemia, which involves elevated levels of fat in the bloodstream and irregular functioning of the particles that carry that fat (what most individuals understand as high LDL cholesterol).
- That individual would be well on his or her way along the path of chronic disease progression, involving a large host of chronic diseases such as type II diabetes, cardiovascular disease.
All-in-all, it is useful to think about how we can make choices that support the body’s ability to utilize fats as a fuel source so that fat does not accumulate in excess (in storage or in any other system in the body) and so that we have the energy that we need to perform functions throughout the day.
How to more efficiently utilize fat as a fuel source (aka, how to burn more fat)
- Stop engaging in behavior that shuts down the utilization of fat as a fuel source in a chronic pattern
Remember up above how I said that being metabolically flexible (the ability to shift between fats and sugars as fuel sources) is a normal and healthy design feature of the human body?
Take a moment to let it sink in that occasionally running and carbohydrates is perfectly healthy….
No, really – pause and let that sink in, maybe even going as far as to think through what that would mean for you and your health-conscious decisions.
I’ll wait.
Got it?
Okay, now that we all appreciate the human body’s amazing ability to utilize both fats and carbohydrates as fuel sources, let’s think deeper about patterns of running on carbohydrates.
If you were to eat a carbohydrate-rich meal, your blood sugar concentration would elevate and you would spend the next several hours running on this sugar. After that, your body would switch back to running on fat (as blood sugar levels drop back down).
But what if you woke up and first thing started consuming lots of carbohydrates? And then what if you had a carbohydrate-rich snack a couple hours later? And then what if you had a carbohydrate-rich lunch, then another carbohydrate-rich afternoon snack… followed by a carbohydrate-rich dinner? And of course, that carbohydrate-rich dessert…
That is, what if you consumed the Standard American Diet, one in which carbohydrates form the base of the food pyramid and are ingested all day long, every single day.
How much time would the body spend utilizing fats as a fuel source then?
The point is, when we consistently consume carbohydrates, the body is forced to run on carbohydrates all the time. And, if the body is running on carbohydrates all the time, then two things are primed to happen:
- Fat might build up in storage.
- The body will likely downregulate the machinery involved in utilizing fats as a fuel source.
The first is easy to conceptualize, and therefore it’s not worth going into much depth. If we aren’t burning fat, then it may build up in excess.
The second might be trickier to understand, and it might be even more important than the first item, so let’s dig into that one:
The body tends to operate with a “use it or lose it” type of programming. For example, we build up muscle mass when we start lifting weights because the body receives the signal that it needs to become more capable of lifting heavy objects; however, when we stop lifting weights, we lose that muscle mass.
Same thing with the machinery involved in fatty acid oxidation: when the body stops burning fat as a fuel source (perhaps because it’s so busy burning glucose), then it will break down the machinery involved in fatty acid oxidation.
Think about what this means for the body’s ability to oxidize fatty acids: less machinery, decreased ability to oxidize fatty acids.
The result? More fat build-up within the body.
How do we fix it?
We stop engaging in behavior that shuts down the utilization of fat as a fuel source in a chronic pattern.
That doesn’t mean that we have to stop consuming all carbohydrates and embrace a low-carb or keto diet. What it does mean is that we stop consuming carbohydrates in a chronic pattern (i.e., all day every day), enabling our bodies sufficient amounts of time to rely on fat as a fuel source.
2. Regularly send signals to the body to build up more machinery to more efficiently utilize fats as a fuel source
There’s another simple answer to address the question of How to more efficiently utilize fat as a fuel source:
We make our bodies more capable of burning more fat:
- we build up more (and more efficient) mitochondria
- we build up more muscle mass
- we build up more vasculature to distribute more energy to our muscles
All-in-all, if we think about behavior that sends strong signals to the body to build up more metabolic machinery, then our bodies will be more capable of using more fat.
Take a moment to think about how this is different from the traditional “calorie balance” dogma that tells us that we need to think specifically about burning more fat (e.g. spend more time doing aerobic exercise to burn more fat during that exercise).
Burning fat during exercise is all fine and dandy, but if you go back and eat a sandwich after that exercise, you’ve just replenished those calories and the net change is zero. Now, that’s not necessarily a problem – if you exercise, it is a good idea to replenish those calories, and if a sandwich is your choice, then that’s perfectly fine.
The point is that the calorie balance model does not take into account this other important part of the whole process, that if you consistently exercise in patterns that signal to your body to build up more metabolic machinery, then your body becomes more capable of burning more fat all the time.
Let’s combine #s 1 and 2 to see how this all plays out as you live your life.
As a recap:
- Stop engaging in behavior that shuts down the utilization of fat as a fuel source in a chronic pattern
- Regularly send signals to the body to build up more machinery to more efficietnly utilize fats as a fuel source
As we regularly engage in behavior that builds up our metabolic machinery (certain types of exercise being a prime example), then we prime our bodies to be more capable of burning more fat.
Now, here’s the key:
Meanwhile, if we stop engaging in dietary patterns that involve the consumption of carbohydrates in a chronic pattern (again, all day every day) then the body becomes capable of releasing excess fat from storage and utilizing it as a fuel source.
Take a moment to note how both pieces are important:
- We need the metabolic machinery in place to be able to utilize fats as a fuel source
- We need to engage in behavior that allows fat out of storage and to be utilized as a fuel source.
At a behavior level, what does this look like?
Well, aligned with The Reprogrammed Systems Approach, when we begin talking about how behavior ties into these pathways, we have to understand that specific practices may be useful for some individuals while they do not serve others. Because of this, we will keep the question at a high level for now.
For now, let’s answer this question simply. As human beings wanting to be supported by bodies capable of using fat as a fuel source:
- We ensure we are regularly physically active so that our bodies regularly receive signals to build up metabolic machinery.
- We are mindful of our dietary patterns so that we aren’t overwhelming our bodies with carbohydrates and locking away fat into storage.
Keep in mind, these are general principles that are to be applied to each individual’s life given his or her own unique circumstances.
How are you going to apply them to your own life?
Bringing in The Reprogrammed Systems Approach to Healthy Living
Got the basics down? Here’s how you can try them out in your own life:
Step 1: Learn to be mindful of carbohydrate consumption and build habits to move your body regularly
Step 2: Dive in a bit deeper on specific exercises and nutrition to get more precise results
In other words, I recommend that you begin your journey to “burning more fat” by thinking about how you can regularly move your body. Meanwhile, focus on being mindful of how frequently you are consuming carbohydrates: are you eating in a pattern that is chronically shutting down pathways of fatty acid oxidation? Or are you allowing your body time to release fats from storage and to utilize that fat as a fuel source?
Now, it’s natural for us to want to jump straight into the details and head to step 2 (e.g. what specific exercise plan can I pretend I’m going to take on every single day to achieve the best results? What specific diet plan can I tell myself I will follow perfectly for the next several months).
We know that mentality doesn’t actually produce the results we need. If you want meaningful and sustainable results, I strongly encourage you to do the two steps in order.
- Begin by building a solid foundation of basic healthy habits.
2. Expand later on by digging into the details (if you want to once you reach that point in time).
That’s the Reprogrammed Systems Approach, and you can learn more about it over at Your Health, Reprogrammed.
