Sugar has been a hot topic in the news lately.  There is a lot of conflicting evidence out there that can be confusing for even the most educated health and fitness professionals.  I find the easiest way to get to the truth is to follow the physiological pathways within the body and develop my own set of opinions on controversial topics such as this.  When it comes to sugar metabolism the process is fairly straightforward.


For today’s purposes, we will just be covering added sugars.  Table sugar, cane sugar, beet sugar, and high fructose corn syrup all fall into this category.  Each of these molecules is composed of sucrose, which is further broken down into fructose and glucose.  Both glucose and fructose take different routes through the body and can have different implications on health, fat storage, and energy utilization.  


Here is how sugar is broken down in the body and how it can lead to us carrying around unwanted pounds.  


When you eat a molecule of sugar it is separated into glucose and fructose, and each of these takes different paths through the body, but they can both lead to fat storage.


Glucose is what most people think of when they think of eating sugar.  Most of us know that when you eat sugar it enters the blood stream in the form of glucose, and it’s the molecule that is always talked about when it comes to insulin sensitivity and diabetes.  Glucose is what our cells use for energy, it is stored as glycogen in the muscles and liver, and our brain relies heavily on glucose to carry out every single function that it performs.  In other words, without the presence of glucose, our bodies wouldn’t have the energy substrates it needs to create the chemical processes that fuel our bodies.  So if it’s so important, why has sugar been getting a bad rap?  The truth is, we eat too much of the stuff.  It’s that excess consumption that starts a cascade of events that cause us to get fat and it can have a direct impact on the development of chronic diseases such diabetes, heart disease, metabolic syndrome, and even Alzheimer’s and dementia through this extra fat accumulation.    


In extremely simple terms, here’s how:


When glucose enters our bloodstream it signals the pancreas to secrete insulin.  Insulin is a hormone that is used to store glucose within the cells of our body.  Insulin binds to receptor sites on cells within the body and act as a transporter for glucose to enter our cells so it can be used for energy.  The more glucose in the blood, the more insulin has to be secreted to aid its uptake into our cells.  The stored form of glucose is called glycogen.  Glycogen is stored within muscle cells and liver cells to be used as a sort of “fuel reserve” to be used down the road.  Like any gas tank, there is a limit to how much glycogen can be stored to use later.  All of the excess glucose needs somewhere to go, so the liver takes the excess and turns it into fatty acids.  These fatty acids are then returned to the blood where they are distributed to the fat tissue to be used as an aerobic fuel substrate at a later time.  


Excess glucose in the blood = more fat storage.


Insulin is a storage hormone and signals the body to save, not burn.  When insulin is present in the blood stream, the body WILL NOT utilize stored fat for energy because it means there is glucose in the blood stream, which is your body’s favorite form of fuel.  



Fructose is the second component of sucrose that we will cover.  It is naturally found in fruits, and it is what gives table sugar its sweet taste.  After entering the body, fructose is absorbed into the blood stream.  It doesn’t have an effect on insulin secretion and is instead shuttled directly to the liver.  In the liver, fructose is packaged into triglycerides and sent back out into the blood stream.  Once it enters back into the blood stream it is then broken down into free fatty acids and is either used for fuel (in the right metabolic environment) or, like excess glucose, it is stored as fat.


As you can see, the end product of too much sugar, by way of either glucose or fructose pathways, leads to more fat storage.


Here is a simple diagram that breaks down the paths that both glucose and fructose take in the bloodstream. 



Important takeaways:


If you want to utilize fat stores for energy, you must manipulate insulin.  In order to manipulate insulin, you must manipulate your carbohydrate and sugar intake.  


Excess glucose is converted to fatty acids and stored as fat.


Fructose is converted to triglycerides, which are broken down into free fatty acids and stored as fat.  


Ways to manipulate insulin and energy storage:


Eat sugar in a post workout meal.  Your body will be in an environment that has a lower glycogen storage tank so glucose will be more apt to be stored as glycogen to top off the depleted stores and not as likely to be stored as fat.


Cut down on overall sugar intake.  Added sugars are in EVERYTHING.  Be sure to read food labels and determine if there is an alternative option to sugar laden choices.  Some popular foods that contain hidden sugars include BBQ sauce, pasta sauce, yogurt, cereal, dressings, ketchup, peanut butter, and granola bars, just to name a few.  


Center your diet around unprocessed, whole foods.  Food that is in its natural state will not contain added sugars.  Opt for fruits and veggies, lean meats, eggs, and healthy fat sources such as raw nuts, coconut oil, olive oil, and avocados.  


If it comes in a box with a barcode on it, it probably contains added sugar!  


Some names for hidden sugars include things such as brown rice syrup, cane juice, carob syrup, caramel, and corn sweetener.  Just to name a few.  If the name sounds sweet, it’s probably a form of hidden sugar.  


Don’t drink your calories.  Avoid sodas (obviously), processed fruit juices, energy drinks, and sports drinks like Gatorade.


Just because something is labeled as “all natural” doesn’t mean it’s sugar-free.  When in doubt, read food labels and ingredients lists!  


It’s time we educate ourselves on the hazards of eating excess sugar and how it can affect your health and fitness goals.  Be accountable for your health and get those added sugar out of your diet!


Josh Soper, BS, CSCS, Pn1