Warning, this is a fairly complex subject and it is difficult to try to communicate it concisely…that is why it’s
taken me so long to finally blog about it…that and I’ve been really busy
wrapping up this session of Boot Camp…and I’ve also been watching the Olympics
in my free time…and there might be a little laziness sprinkled in there as
well.
I want to put out a disclaimer that I am going to
significantly summarize the physiological processes that take place in dealing
with carbohydrate ingestion, conversion, storage, etc. Partly because I don’t
know how many of you actually want to read all that…and partly because I am
just not that smart and would probably screw something up if I tried to pretend
that I was that smart J
I do want to try to explain some important concepts in
layman’s terms, and then try to address some of the misconceptions I’ve heard
about carbohydrates. Carbohydrates are an incredibly important macronutrient,
but how you utilize them should be drastically different depending on the goals
that you hope to achieve. BTW…I’m also assuming that you are reading this post
in the context of the series on nutrition in context, so you already know about
weight loss and calories, etc. Nothing in this post contradicts anything I
wrote about calories, so don’t think that if you focus on carbs and ignore
calories you’ll effectively hit your weight loss/gain goals.
How your body uses Carbohydrates:
I’m sure you already understand the concept that food is the
primary source of energy for your body. If you don’t expend that energy in some
way, your body will store it. Your body stores energy from carbohydrates in two ways, temporary
storage as glycogen, and more long term storage as body fat. Remember that
calories are the energy source for your body, but the content of the calories
are used in different ways by your body. The 3 primary macronutrients that your
food contains are carbs, proteins, and fats. Each of these macronutrients
contain a specific calorie content…which I mentioned in a previous post.
When you eat carbohydrates, your blood sugar (glucose) level
rises. This rise in blood sugar triggers your pancreas to secrete the anabolic
hormone, insulin. Insulin is considered an anabolic hormone because it triggers
the intake of nutrients for repair/growth/storage (anabolic = grow, catabolic =
shrink). The resulting action is the intake of glucose from the blood in order
to regulate your blood sugar level. The intake of glucose is stored as glycogen
in your muscles for repair/regrowth and into your liver for storage and a
variety of necessary physiological functions. When your body stores more
glycogen reserves than it needs (energy excess) the glycogen eventually gets converted
and stored as fat.
On the flip side, when your blood sugar levels are low, your
liver converts stored glycogen into glucose to regulate blood sugar levels. In
healthy persons, usually the only time you are going to have a decrease in
blood sugar level to trigger the release of glycogen from the liver is after
intense or prolonged exercise, or if you are in a low carb or fasted state. Once the liver exhausts it’s stored glycogen
(typically after 8-12 hours with no other activity), the body digs into fat
reserves which are eventually converted into glycogen and released from the
liver to regulate blood sugar.
The Glycemic Index and Simple Vs. Complex Carbs:
You’ve heard about high glycemic Index (GI) carbs and low GI
carbs. You’ve heard about simple carbs and complex carbs. For the most part
they are one in the same. Simple carbs (high GI carbs) are broken down by the
body rapidly, significantly increase blood sugar, and spike insulin levels.
Complex carbs (low GI carbs) break down more slowly, do not increase blood
sugar levels significantly, and do not spike insulin levels much. To complicate
matters further, you not only have to consider the glycemic index of the carbs
you are eating, but the total glycemic load. In other words…portion control!
50g of a complex (low GI) carb may spike blood sugar levels higher than 25g of
a simple (high GI) carb.
You’ve probably heard or read that simple carbs are bad, and
that you should avoid them and eat only complex carbs. For example…eat sweet
potato (complex) versus white potato (simple) or eat wheat bread (complex)
versus white bread (simple). If this advice is taken in the proper context, it
can be good advice. However, as I’ve been trying to point out throughout this
entire series, context is everything…and many sources that solicit this advice
don’t bother to take the time to put things in context. There are circumstances
where simple carbs can be very beneficial for your goals and other
circumstances where they will be detrimental.
Carbohydrate strategy for muscle growth
If your goal is to build muscle, you will want to utilize
simple carbs immediately before, possibly during, and immediately after a
workout. Why? Because immediately after an intense weight lifting workout, your
muscles are depleted of muscle glycogen and spiking your blood sugar and
insulin levels through simple carbs is the fastest way to reload your muscle
glycogen and begin the rebuilding/repair/growth process.
Simple carbs should
probably be avoided outside of the workout window (let’s call the workout
window less than 1 hour before your workout, and less than 2 hours after your
workout) as once you refill your muscle glycogen, the rest of the glycogen will
be stored in the liver and if not utilized for energy will be stored as fat.
Therefore, simple carbs can be helpful in a muscle building strategy…but only
if properly utilized. Outside of the workout window, complex carbs are a better
choice.
Also, focus more on starchy carbs versus sugary carbs as a greater
portion of the glycogen in starchy carbs will go towards muscle glycogen.
Breads, cereals, potatoes, rice, etc. are starchy carbs. Sugary carbs are ice
creams, sugars, syrups, fruits, etc. Keep in mind, this strategy will help
create an environment an environment to help build muscle assuming proper
exercise and protein intake…but it is not a good strategy to burn fat.
Carbohydrate strategy for fat burning
If your goal is to burn fat, a low carb strategy isn’t a bad
idea. However, depending upon your workout load, you will still need some carbs.
My suggestion is that you do try to avoid simple carbs, and focus on eating a
reasonable amount of complex carbs within your workout window. Outside of that,
limit carbs…especially later in the day when your body doesn’t need the energy.
If you go to bed depleted of glycogen, you’ll burn more fat while you sleep.
Keep in mind that ALL OF THIS IS DEPENDENT UPON
YOUR CALORIC INTAKE. You can go low carb all you want, but if you eat an
excess of calories through excessive fats and proteins, you’ll still struggle
to lose weight. Also keep in mind that when you replete carbs, you will lose
water weight. Therefore, don’t be surprised if you see some immediate weight
loss in the first few days of a low-carb diet…but understand that you are
mostly losing water weight. Also, don’t get discouraged if you have a weekend
binge where you eat plenty of carbs and gain all of the weight back…more than
likely that is water weight as well due to the carbs. Finally, keep in mind
that this strategy will make it very difficult for you to build, and in some
cases maintain your lean muscle.
Combined muscle growth and fat burning
The most efficient way to both build muscle and burn fat
that I’ve found is through Intermittent Fasting. Why? Because you can combine
both of the strategies above by partitioning your days and weeks. You can have
a muscle building (anabolic) window, and a fat burning (catabolic) window. In
your fasting window, you deplete glycogen and your body taps into its fat
reserves to regulate blood sugar. In your feeding window, immediately after you
workout, you can reload your glycogen stores quickly so that your muscles begin
rebuilding immediately. For those not familiar with IF…have you not read the
rest of my blog? Haha…no worries, here is a very brief summary:
- 16 hour fasting window each day – no calories
- 8 hour feeding window each day – majority (approx 60%) of calories in first meal
- Exercise during the fasting window
Ideally, I would be able to workout from 10:30am to 12pm
everyday and immediately eat my first meal of the day at 12pm. Unfortunately, I
don’t get paid to blog, so I have to work. Therefore, I workout at 5am, and
don’t eat until 12pm. Does this potentially limit my ability to pack on muscle?
Probably some, but it does increase my ability to burn fat. However, on the
weekends I can workout and immediately eat afterwards…I love weekends! The
first meal of the day should be heavy on carbs (simple carbs are welcome) and
protein. I limit the amount of calories I am getting from fat because they are
not efficient calories in helping to build muscle. Later in the day, I’ll try
to eat more complex carbs instead of simple carbs. On the days I don’t workout,
I’ll try to go low carb all day long, and avoid simple carbs. This is because I
don’t need the carbs for energy/rebuilding, and I can focus on fat burning.
Summary
So there you have it. You know how the body absorbs carbs
and regulates blood sugar. You know what the Glycemic Index is all about and
what simple versus complex carbs mean. And hopefully this blog post helped you
to better understand and develop a strategy to have carbs work for you. So,
next time you read an article that talks about carbohydrates, you can put it in
proper context, and determine if the advice makes sense for you or not.
