Once carbohydrate-containing foods are digested, individual glucose molecules are released throughout the body. Moderate carbohydrate consumption leads to the immediate use or storage of these glucose molecules. However, if excess carbohydrates are consumed a process called de novo lipogenesis occurs. De novo lipogenesis is a complex metabolic pathway which converts glucose to fat, and that fat is stored in adipose tissue.

So too many carbohydrates in your diet could lead to weight gain. How does this happen?

Carbohydrate-containing foods are digested and individual glucose molecules are free and move throughout the bloodstream. The pancreas secretes insulin which allows cells to take in glucose and use it to produce energy for our body’s needs. Extra glucose is taken in by the liver and muscles and stored at glycogen (large molecules comprised of glucose) for later energy needs. But the liver has a glycogen capacity. If there is more glucose in the bloodstream than what cells and the liver need, de novo lipogenesis occurs and glucose is converted to fat.

But this process only occurs when the total energy (calories) intake exceeds that of total energy expenditure. In other words, the conversion of carbohydrates to fat occurs only if you are not using more energy than you are taking in. Using less calories than what you are consuming is called being in a positive energy balance (more energy going in than energy going out).

What does this all mean? It is important to consume carbohydrates in moderation and to be physically active. These steps will help to prevent the conversion of carbohydrates to fat, and therefore help with overall weight maintenance.
Sondra Tunon

Sources:
https://www.ncbi.nlm.nih.gov/pubmed/10365981
http://news.berkeley.edu/2012/12/06/gene-converts-carbs-to-fat/

Image:
https://commons.wikimedia.org/wiki/File:Blausen_0012_AdiposeTissue.png