The process of nutrient metabolism differs depending on which macronutrient is concerned.
Fats, proteins, and carbs all have different roles after all, so it only makes sense that the process of digestion and metabolism involved is different too.
In this article, we’re going to look at how carbohydrate digestion begins in the metabolized.
Carbs, being one of the 3 macronutrients, are a useful energy substrate.
In fact, carbs are the preferred energy source because of how easy they are to metabolize compared to the other two, fat and protein.
But in recent times, carbs have gained a bit of a notorious reputation from a health and nutrition perspective.
The rampant epidemic of metabolic diseases such as type 2 diabetes and morbid obesity has been linked to the excess consumption of carbs available in the modern western diet and mainly in the form of sugar.
This has lead to many movements and nutritional protocols that place a dietary embargo on carbs.
Low carb diets, foods and entire subcultures based on the demonization of one of the 3 most fundamental nutrients for life.
So why is this class of molecules getting such a bad rap?
What’s So Bad About Carbs?
Carbs aren’t bad, at least not as bad as they are often portrayed, but there is a reason.
The story of the shunning of carbs can be traced back to the late 1960s, a time where industrialization, including that of food manufacturing, was at an all-time high.
This correlated with an unprecedented rise in metabolic diseases, especially obesity.
Never before in human history had the rampant rise in an overweight population been recorded.
This prompted the attack on fat. It made sense at the time to imagine that high levels of fat in the diet lead to high deposits of it in the body.
But a deeper look soon revealed that fat was in fact not the primary cause.
It was actually the excess prevalence of refined carbohydrate digestion begins in the form of sucrose and high fructose corn syrup.
But the running sentiment was that carbs as a whole were bad, and bad in the way that they made people fat.
This has given rise to many diets and some would say, ideologies, that demonize the consumption of carbohydrates.
The reality is, its a quality and quantity situation.
The quality of carbs, just as with any other food is important in determining its usefulness to health.
When you fill-up your car at the pump, you try and use the most premium fuel available, not the cheapest, dirtiest version.
The same thing with carbs, if all you eat are refined, simple carbs, you won’t be doing yourself any favors.
Go for complex carbs and fiber which allow you the opportunity to digest in a mediated way that doesn’t throw your insulin sensitivity out the window.
Quantity is also a factor. Try and maintain a balanced intake unless you have specific needs and recommendations.
What Are Carbs Used For
Carbs, as we’ve mentioned are an important macronutrient, they are the most readily available energy source owing to the fact that they are so easy to metabolize.
Your brain is especially reliant on carbohydrates for optimal function.
But how exactly do carbs play this important role?
In this article, we’re going to take a closer look at how carbs actually work in your body from the moment you consume them.
The Process of Carb Digestion
Carbs are digested and processed through 5 different pathways or metabolic systems which all work together for your healthy function.
Glycogenesis is the formation of glycogen from glucose.
Glycogen is a storage molecule that acts as an energy reserve for muscle contractions and metabolic activity.
It is stored mainly in the muscle and liver cells when a reaction triggered by insulin causes these cells to absorb glucose and convert it to more stable glycogen.
Glucose is one of the most basic forms of carbs and increases in your blood when you eat foods containing complex carbs or glucose itself.
The presence of glucose triggers a release of insulin which then signals the relevant cells to take it in and store it as the more complex glycogen molecule.
Once in this state, glycogen is now available to be used when the body’s energy demands rise.
One thing to keep in mind is that the insulin activity that converts glucose to glycogen is very delicate. If excess amounts of blood glucose occur chronically, your cells respond to the insulin signal decreases.
This is called insulin resistance and can lead to type 2 diabetes and an increase in fat molecules which leads to obesity.
Keep your insulin sensitivity in check by eating high-quality complex carbs which won’t raise your glucose levels too high. These are known as low GI carbs.
Glycogenolysis is the opposite of glycogenesis.
This is the break down of glycogen into glucose, allowing the simple carb to be used in energy conversion reactions.
This is the ultimate purpose of glycogen that is stored in muscle and liver cells. The break down of glycogen to glucose is triggered by the enzyme glycogen phosphorylase enzyme.
In order to use the glucose from glycogenolysis, which is in the form of glucose 6-phosphate, your body must convert it into a molecule called pyruvate.
This process is initiated by special enzymes, pyruvate or pyruvic acid in the precursor to ATP, the energy currency of your cells.
4. Krebs cycle and electron transport chain
Once pyruvate is produced, it is converted to a molecule called acetyl-CoA.
At this stage, oxidation occurs in a process where CO2 and water are created as byproducts of the oxidative reaction.
This is triggered in part by the oxygen you breathe.
The result is ATP, giving your body the energy it needs.
Sometimes you can’t get the right amount of carbs for your body’s demands. Either due to being in a deliberate fasted state such as intermittent fasting or keto or because your activity levels demand more energy than you have in the form of glucose and glycogen.
In such cases, your body has devised ways of creating carbs out of non-carb sources. This is called gluconeogenesis.
Your body, and especially your brain, will call on your liver to create carbs from 4 fundamental sources. These are:
- Lactic acid
- Pyruvic acid
- Amino acids
- And glycerole, a building block of fats
This process is basically the reverse of glycolysis and is initiated in times of need.
Carbs are not just good for you, they are essential.
Your brain demands nothing else for its healthy function as do other organ systems carbohydrate digestion begins in the body.
A low carb diet certainly has proven health benefits, but that just means the carbs you’re not getting through your diet are being produced internally to satisfy your natural requirements.
The moral of the story is, carbs are good and carbs are essential, it all just depends on quantity and quality.