What Happens When You Eat Carbs?
Carbohydrates are in almost every thing we eat. They’re in processed foods, fruits, vegetables, nuts and dairy. Just about the only place you won’t find them is in meat (beef, pork, poultry and fish). When we’re trying to eat healthy we’re often told to eat less carbs. We hear about bad carbs and good carbs, but what does it all mean and what actually happens when we eat them?
When trying to lose weight we’re told to stay away from “bad” carbs. Often that’s interpreted to mean all carbs are bad, but that’s not the case. Our bodies and especially our brains need carbs to function.
In addition to carbs being called good or bad, you may also have heard terms like “complex carbohydrates” and “simple sugars” or references to the glycemic index. Here’s some insight on how it all fits together…
What makes a carb good or bad has to do with the way the body processes it. That’s where the glycemic index comes in. The glycemic index is a measure of how quickly the sugar in a food enters the blood stream. The faster the entry into the blood stream the higher the score on the glycemic index. Simple carbohydrates (sugars) are more readily processed by the intestines and more quickly released into the blood stream as glucose causing a spike in blood glucose (commonly referred to as a spike in blood sugar). This triggers the body to release insulin which manages blood glucose levels.
When blood glucose levels rise quickly, insulin is needed to remove some of it from the blood in order to keep the blood sugar level in the optimum range for the body to function properly. Insulin is commonly known as the “storage hormone”. The insulin goes to work removing glucose from the blood and storing it as glycogen. First it’s stored in the liver, then in the skeletal muscles. When those storage areas are full (here’s how much they hold *), the excess glucose gets stored as body fat.
When you consume “good” or complex carbs the intestines have more work to do in order to process the carbohydrates and release them into the blood stream as glucose. This means that blood glucose levels rise more slowly and over a longer period of time. Insulin will still be released to manage blood glucose levels, but since there’s less glucose to deal with at any one time, it’s more likely that there will be space available in the liver and muscles… and there’s less chance it will get stored as fat.
In order to make space for more carbs we have to use up the carbs we already have stored. Since the carbs are a primary fuel source we use some of our supply just by existing. All our bodily functions require fuel. So, even if you lie on the couch and do nothing you’ll use up some of your carb stores.
However if all we do is lie on the couch (i.e. live a sedentary lifestyle) we tend to regularly consume more carbs than the liver and muscles can hold before we have a chance to use much of it up. Yet another reason to exercise… physical movement causes the body to use up these stores much more quickly making room for those carbs to be stored without turning to fat.
*Between the liver, muscles and bloodstream about 2100 calories of glucose can be stored before glucose is converted and stored as fat (ref. http://www.extension.iastate.edu/humansciences/content/carbohydrate).