The Cause Obesity Part 3: Eating Carbohydrates

“Eat carbs…don’t eat carbs…don’t eat fats…OK, eat fat…superfood this…superfood that”.

Food has become like an episode of Prison Break. No one knows what the hell is going on anymore!


People often subscribe to a certain way of eating, whether it be “low carbs” or “low fat” or “intermittent fasting” but, most don’t have a solid grasp of the basics. You can’t build a house without a solid foundation so, let’s lay the foundation (for myself included). First, let’s cover carbohydrates or “carbs” as the hipsters call it these days. #nerdup

So what is a “carbohydrate”?

Carbohydrates are bloody complex and are made of building blocks just like lego. These building blocks are called monosaccharides or “simple sugars”. There are only three; glucose, fructose and galactose.

When two monosaccharides join forces, they form disaccharides. For example, sucrose or table sugar is made up of glucose and fructose. Lactose, the carbohydrate commonly found in milk, is made of glucose and galactose.

When three or more monosaccharides join forces, you get what’s called a polysaccharide. For example, starch and fibre are polysaccharides made of massive chains of glucose. Wait, fibre is a carbohydrate? I thought fibre was good for you? But, I thought all carbs were the devil? Quick disclaimer: cutting carbohydrates completely is different to cutting sugar. An important distinction to make.

If you noticed, glucose features in pretty much everything. Just like an attention seeking teenager, everything seems to revolve around glucose.

So what happens when you eat carbohydrates?

Whichever way you eat them, the body essentially breaks them down into monosaccharides (glucose, fructose or galactose). These monosaccharides are then absorbed and taken to the liver. The liver is a like a 54 year old mother of two in China working her second job manufacturing clothing for the Western world. In other words, it does a heap of work but doesn’t get much recognition for it. Anyway, the liver does  some crazy magical abracadabra-type voodoo stuff to all these monosaccharides and converts pretty much all of it into glucose. Classic attention seeking teenager behaviour.  The glucose is then released into the blood and begins to fulfill its role as the body’s favourite energy source.

When glucose enters the blood, the pancreas knows immediately. As if glucose is a long lost love, it knows as soon as they are in town. In response, the pancreas releases something called insulin. Insulin works to help the glucose enter the body’s cells thereby allowing it to perform its magic. Without insulin, cells would not be able to get enough glucose. Thus, there would be not be enough energy produced to perform the body’s usual activities whether it be to keep your heart pumping, your lungs breathing or recall the names of each member of One Direction . In other words, how carbohydrates are ultimately used comes down to how quickly your pancreas releases insulin and how well it works on cells to allow glucose to enter cells.

Are you still with me? If so, let’s continue. #nerdup

Once glucose enters cells, one of three things can happen and it happens roughly in this order.

  1. It is used immediately. After a series of super complicated reactions, glucose provides energy to the body in the form of ATP. If you want to learn more about these complex reactions, look up things like aerobic respiration or glycolysis or citric acid cycle. A quick shout out to the scientists who figured this stuff out in the first place! I found it hard enough to understand let alone discover.
  2. After all the body’s energy needs are met, it’s time to store some away for a rainy day. Any extra glucose is converted into a substance called glycogen which is essentially a glucose store found in most cells but, mainly in the liver and muscle. Essentially if the glucose levels drop low and your body needs a quick fix of the good stuff, it can break down this glycogen and live to find another day. Or more accurately, live to fight another 12-24 hours. Glycogen is a finite resource. You can only store a few hundred grams of glycogen so sorry to be the bearer of bad news but, it runs out.
  3. After the body stores the excess glucose as glycogen for a rainy day, it prepares for a storm. Any further excess glucose is stored as drum roll please…FAT! Once again, a whole lot of reactions and voodoo stuff happens here but, the crux of it is that any excess glucose is converted in the liver to fat and then transported and deposited in different parts of the body. Who would have thought love handles orginate from the liver performing voodoo. The body does this because fat is much more efficient at storing energy. In fact, it can store more than twice the amount of calories for the same weight as carbohydrates. Also, like I stated earlier, only a few hundred grams of glycogen can be made and stored but you can store kilograms worth of fat (as you may have noticed). Fat is great because if there is a “storm” and you are for example fasting or even starving, the fat can be broken down and used as energy. The problem with obesity is that the storm never comes (not that I condone starvation).


So what happens when glucose stores are low?

When carbohydrates, namely glucose, are recognised to be low inside cells or in the blood your body momentarily freaks out because its essentially low in its main energy source. It’s cloudy with a 100% chance of rain so our glycogen stores are broken back down into glucose. If levels are still low, the body can also do this cool thing called gluconeogenesis (sounds like an experiment they would perform on X-Men right?). What this essentially means is that the body will take things that are not carbohydrates and create glucose. It’s frickin magic. This process, happens mainly in the liver and uses the amino acids (from protein or muscle) and the glycerol (from fat) to undergo some more abracadabra voo doo to form glucose. There is that attention seeking teenager again! This glucose can then be used for energy.

There is of course another option. If levels are still low, a storm is brewing. Essentially, fat stores are broken down and are taken to cells which need energy. As mentioned earlier, fat is bloody efficient at storing energy and so it can release large amounts of ATP if needed for bodily functions (and I dont just mean dropping a deuce at 2 in the morning).



-Carbohydrates are broken down into monosaccharides (glucose, fructose, galactose), absorbed and taken to the liver.

-The liver converts most of the monosaccharides into glucose and releases the glucose into the blood.

-The glucose in the blood is detected by the pancreas and insulin is released to help glucose enter into cells.

-After entering cells, glucose is either used immediately, stored as glycogen or stored as fat.

-When glucose levels are low in the blood or inside cells, the glycogen is broken down, glucose is formed through gluconeogenesis and fat is broken down to provide an alternative energy source.


As always, don’t do drugs, stay in school and enjoy the latest season of Prison Break. Seriously, how many times can they break out of a prison!?! If you find any value in this stuff, share the love. If you want to add knowledge or insight, PLEASE do.

Related posts:

The Cause Of Obesity Part 1: Big Picture

The Cause Of Obesity Part 2: Changing Bad Habits

The Cause of Obesity Part 4: Eating Fats

Weight Loss Solutions: Sustainability 

The whole (food) does not equal the sum of its parts


Dr G