Mar 6, 20203 min read

Do Carbs Turn Into Sugar or Fat? [De Novo Lipogenesis and Weight Gain]

Updated: May 27, 2020

There's a TON of confusing information surrounding the topic of Nutrition and weight loss. Are carbs the enemy? Will fat "make you fat"? It's especially difficult when you're trying to find the answer that will BEST help you to achieve your weight loss and wellness dreams.

Today, I'm breaking down the details of a common (and important) question: Do carbs turn into sugar or fat? Providing clarity and understanding the science behind what happens to carbohydrates in your body will help you make the meal choices you need in order to tap into fat burning mechanisms and feel GOOD again!

First, What Are Carbs?

Carbohydrates aka carbs are one of the three macronutrients that you can consume. The other two macronutrients include protein and fat. Carbohydrate rich foods include grains, beans, potatoes and squash. The foods most dense in carbohydrates include sugars and refined grains. For example, a bowl of pasta or a sugary pastry will contain more carbohydrates than beans and vegetables.

Carbs can come in a variety of forms, but they are typically classified based on the length of the chain of connected carbs. For example, one single carbohydrate unit is considered a simple sugar. These are very easy to absorb in the body because they require zero breakdown in the GI tract in order to access the sugar.

On the other end, you have starches. Starches are multiple sugar bases connected with something called a glycosidic bond. This bond must be broken down in the GI tract before you can absorb the individual sugars. This can slow down the release of the sugars into your system.

What Happens When You Eat Carbohydrates?

Let's take a walk through your GI tract to discover what actually happens to the carbs you eat. When you're chewing on a meal rich in carbohydrates, your body is taking the first step of manually breaking down your food. Not much further breakdown of carbohydrates happens again until the small intestine. This is where your body chemically breaks down your food. It's during this time that starches are broken into individual sugars and absorbed in the body. If the food you eat is already in the most simple form (aka sugars), your body doesn't need to chemically break it down before being absorbed.

No matter whether you eat starches or simple sugars, all digestible carbohydrates will convert into sugar before being absorbed into your blood supply.

The Role of De Novo Lipogenesis (Carbs to Fat)

In Nutrition, Physiology and Medical schooling, something you typically learn in the first year are common latin roots. This helps you speak and understand the "language" of the science of the body. Because at the root of it all, medical and biological terminology is essentially another language.

De Novo Lipogenesis is the process of carbohydrates being converted to fats. It sounds like a big scary word, but when you break it down with the latin roots, you get "de novo" meaning "of new", "lipo" meaning fat/adipose tissue, and "genesis" meaning "the creation of". So De Novo Lipogenesis literally means "making new fat".

When your body breaks down and absorbs the sugars into your blood supply, the first response of your body is to release the storing hormone, insulin. Insulin shuts off lipolysis (fat break down) and works to start storing the sugars that you just consumed.

This storage of sugars first acts on your muscles by converting the sugars to muscle (or liver) glycogen. Glycogen is similar to starch in the sense that it's a long chain of carbohydrates.

You breakdown food starches into sugars in order to convert them back into a "starch-like" substance (glycogen) to be stored in the body.

However, there's a fairly limited space for glycogen storage. When this is full (which happens fairly quickly), the remaining sugars that need to be stored get converted into fat through the process called de novo lipogenesis.

So the answer to whether carbs get converted into sugar or fat is... it gets turned into both. Depending on how many carbs you eat and how quickly they are absorbed, the carbs you take in can turn into both sugar AND fat.

This is an important concept to understand, especially if weight loss is your goal. In fact, if you are looking to lose weight, check out THIS article on the uniquely fattening capabilities of carbohydrates and what you can do about it.