Carbs 101


What is a carb?

There are three main macro nutrients the body uses. Carbohydrates (carbs), protein, and fat. We ingest them with our diet. Carbs come in different forms: Sugar, starch, and fiber. We will leave fiber for another time.

Are all carbs the same?

Yes and no. Carbs, may they be complex, organic, in veggies, in soda ... all carbs end up as glucose that the pancreas must deal with; or fructose, that the liver must deal with. Carbs from low carb veggies don't spike glucose levels as much as carbs from potatoes or soda. But the body must still deal with the entire glycemic load.
Sugar alcohols are also carbs. Except for maltitol they generally have no effect on glucose levels.

But what about complex carbs?

Complex carbs are just longer chains of glucose. They quickly dissolve into glucose when we start chewing our food.

Why do we eat carbs?

Carbs offer fuel for our body. It is a convenient and shelf stable food. It is cheap and most profitable for the food industry. But the body burns through carbs quickly and excess carbs are easily stored as energy in the form of fat. Yes, fat doesn't make us fat. It's the carbs.

Do we need carbs?

Carbs are not essential. While the human requirement for carbs is exactly zero, certain amino acids and fatty acids are vital for human survival. Scientifically these are called essential. Carbs don't contribute in any way toward body maintenance, body functions, body processes or tissue maintenance and growth.

Does the brain need carbs?

Our brain needs glucose, tiny amounts BTW and for the most part it prefers ketones. That does not mean we have to ingest glucose. The liver happily converts protein to glucose in a process called gluconeogenesis (this may be different with end stage liver disease or other certain health conditions).

Carb addiction?

When the body is used to energy in the form of carbs, the brain will prompt us for a constant flow of carb intake. It's not unusual (and even recommended) to have several small meals every day. Carbs raise glucose levels substantially. Shortly after, glucose levels drop, causing us to crave more carbs. It's a vicious cycle that ends up making us insulin resistant. Carb addiction is a real problem. Carbs are as addictive as cocaine. It triggers the same reward center in the brain. While we can stay off recreational drugs, we cannot stop eating. That is one reason why a carb habit is so hard to break. But how to break carb addiction? For most people including myself, we must completely abstain from processed carbs and glucose. In moderation (link to blog) does not work.

Preferred fuel or first fuel, what is the difference?

Glucose it not the preferred energy source, it is just the first energy to be burnt off. That is a big difference. The body prefers fat for energy. That's also why energy is stored as fat.

What happens to carbs in the body?

The body burns through carbs fast; excess carbs are quickly stored as fat, because the body needs to remove glucose from the blood. In a short amount of time the brain signals hunger again, prompting us to eat more carbs. Carbs won't keep us full because they don't trigger any satiety receptors. Fat and protein do trigger satiety. They are very hard to overeat. After a meal we may feel nauseous at the sight of a piece of meat but have no problem to eat a good-sized dessert. Diets high in carbs (in other words high in sugar) cause inflammation and glycation in the entire body. Inflammation causes all sorts of problems including injuries to blood vessels causing cardiovascular disease. Glycation causes faster aging.

What is the problem with carbs?

The ability to process carbs is impaired in people with insulin resistance and even more so with full blown Type 2 diabetes. 88% of the US population is metabolically sick. Given those numbers, it would seem sensible to restrict carbs. How many carbs we tolerate depends on how severely insulin resistant we are. Other health conditions might play into this too.

What does that mean for people with insulin resistance?

Excess glucose is turned into fat. At any given moment, only about 4 to 5 grams of glucose circulate in our blood. Put that into perspective with high carb diets. Imagine flooding the system with the recommended 225 g to 325 g carbs per day. This will overload the system, every single day. It is disastrous for people with insulin resistance. The body must try its best to quickly remove glucose from the blood. When we consume carbs often throughout the day, insulin levels are chronically elevated, setting the stage for insulin resistance.

But aren't we all different?

Yes and no. Humans don't need carbs, but with certain conditions the liver cannot convert protein to glucose. This would require dietary carbs. Also, people on glucose lowering drugs may require carbs to avoid hypoglycemia, when glucose levels drop too low for safety or to bring them back into normal range.

Final thought: "Healthy carbs" is a term coined by the food industry. It's a clever marketing trick that was pretty effective. Nothing about carbs is healthy. Heart healthy cereal? No, they are ultra-processed food that needs to be fortified to have any nutritional value. Before big food, carbs were known as fattening carbohydrates. Farmers know to this day, that to fatten cattle quickly, they need to feed them grains.

Written by Roxana Soetebeer
Fact-checked by Dr. Ben Zacherl
Published: July 17th 2021