While there are many passionately debated nutrition topics, few create as much passion and interest as carbohydrates (aka carbs). Popular low-carb diets like Zone, Atkins, South Beach, and Paleo limit the intake of carbs, while others like the Ornish diet call for high carbs as the way to health.
Who is right? Are carbs evil? What are carbohydrates anyways?
While carbohydrates can be a very confusing subject, I'll try to break down all the important concepts related to carbohydrates to turn a confusing subject into a simple one.
What are Carbohydrates?
Carbohydrates are found in foods including fruits, vegetables, grains, potatoes, pastries, and candy and are considered the bodies preferred energy source. Hopefully however you don't choosepastries and candy as a regular source of fuel :/ More specifically, carbs are sugar molecules that are made up of carbon, hydrogen, and oxygen. Carbs are one, or more sugar molecules that are bound together and broken down by the body to be used as fuel.
Here’s a quick list of carbohydrates:
Types of Carbohydrates
Carbohydates are looked at in many different ways:
healthy vs. unhealthy
good vs. bad
slow vs. fast
simple vs. complex
No wonder it's so confusing to people!
Remember, carbohydrates are just sugar molecules, all of which are broken down by the body into glucose.
There are 3 types of carbohydrates that are defined by the number of sugar molecules they contain:
1) Monosaccharide – one sugar molecule, examples include glucose, galactose (in milk), and fructose (in fruit)
2) Disaccharide – two sugar molecules, examples include sucrose (table sugar), lactose (in milk), and maltose (in beer).
3) Polysaccharide – several sugar molecules, examples include starchy foods like pasta, or potatoes, and fiber, which is the indigestible part of a plant that aids in digestion.
When a carbohydrate is “simple” it refers to mono & disaccharides that are easily absorbed into the bloodstream because of their simple molecular structure. Think milk, fruit, and table sugar. “Complex” carbs on the other hand are polysaccharides and because of their more complex molecular structure can take longer for the body to break down into sugar. Think grains, vegetables, and potatoes.
You may be thinking, “Ok, so simple carbs are bad and complex carbs are good, right?” The answer is not that simple as you’ll learn in a moment.
Function of Carbohydrates
Before you can understand what carbs to eat,youe need to understand how carbohydrates are used and stored in the body.
As carbohydrates are broken down and enter the bloodstream, they increase the amount of sugar (glucose) in the bloodstream. The level of sugar in the bloodstream is called your blood sugar level. As you eat carbs, your blood sugar level rises, which activates the hormone insulin to suck the excess sugar out of the bloodstream and into your muscles (which can absorb about 300-400 grams) and your liver (which can absorb 100 grams).
What happens if your sugar storage tanks (muscle & liver) are full and you keep on eating carbs? Any excess glucose that is not used by the body for energy will be stored as fat. The more “insulin sensitive” your muscles are, the more readily they will suck in sugar instead of having that sugar get converted to fat. And what’s a great way to make your muscles more insulin sensitive? Strength training of course!
Good Vs. Bad Carbohydrates
Many nutritionists do not use the word “bad” when describing food because as the saying goes, “there are no good, or bad foods, only good, or bad diets”. With that said, carbohydrates that cause your blood sugar level to rise rapidly are generally considered "bad", or unhealthy carbs whereas those that are absorbed slowly and have little effect on blood sugar levels are considered good, or healthy carbs.
The Glycemic Index was created to measure the speed with which carbohydrates are converted to glucose. Foods that digest quickly are high on the index, which ranges from 0 to 100, and foods that digest slowly are lower on the index. This is important because large spikes in insulin levels affect your hunger (can make you even more hungry), can negatively impact fat loss, and even lead to diabetes if levels are chronically elevated from over consumption of fast digesting or "simple" carbohydrates.
Here’s a short list of some high and low glycemic carbohydrate foods:
While the Glycemic Index can be helpful, it’s not perfect. For example, some ice cream can show up as 30 on the glycemic index, along with some other carbohydrate sources like spaghetti that provide substantial calories in small servings. In addition, foods like watermelon that are high on the Glycemic Index impact blood sugar levels far less when adjusted on a per serving basis (watermelon is mostly water, hence the name). This concept is referred to as the Glycemic Load. (way to go Terri, you were supposed to simplify this stuff) Lastly, when combining the carbohydrates with different foods like dietary fat, the pace of digestion can slow down.
Confused? Don’t be. If you are eating whole, natural, unprocessed carbohydrates, you can consider them a good carb, but if the carb was made in a lab, or has been processed such as soda, candy, or white bread, it’s a “bad” carb, or better yet – not ideal. I don’t like using the bad word unless describing High Fructose Corn Syrup, which is a chemically altered sugar found in tons of foods we eat every day. More on HFCS another time! THAT crap deserves its very own post!
Do Bad Carbs Make You Fat?
I wish I could answer this question easily, but even an experienced researcher with a PHD would cringe at the thought of a proper answer.
There are two primary ideas that attempt to describe how we gain and lose fat:
1) Energy Balance Theory – If you eat more calories than you burn, and you gain weight and if you eat less calories than you burn, you lose weight. This theory is based on the law of thermodynamics where energy can neither be created nor destroyed. You can eat as many carbs as you like and as long as you eat less total calories than you burn, you will lose weight. Harvard Medical School, The Institute of Medicine, along with most large and reputable organizations support this theory.
2) Carbohydrate Hypothesis – Carbs, not calories make you fat is the summation of the carbohydrate hypothesis. Proponents include Dr. Robert Atkins, Dr. Michael Eades, and other medical and nutrition experts who view carbs as the root cause of the obesity epidemic. As long as you sufficiently decrease your carb intake, you will lose weight.
Who’s right? Well that’s worthy of a separate blog post for sure, possibly even a book, but my thought after 26 years in the business is the truth lies in the middle; eating less calories helps you lose weight, but eating too many carbs and not enough protein may have you gaining fat, and probably even losing muscle. As well, genetics, hormones, and activity level play a huge role in how easily carbs are stored, used as energy, or converted into fat.
Eating some candy, or cookies here and there will not make you fat, but eating a lot of fast digesting carbs combined with excess calories and no exercise is a great strategy for adding a bunch of body fat.
How Many Carbs Should You Eat?
The amount of carbohydrates you should eat depends primarily on your genetics, body size, and activity level.A custom meal plan designed specifically for you by an experienced Trainer with a nutritional degree is one way of figuringing this out.
From an evolutionary standpoint, carbohydrates are not essential, which means we do not need to consume carbs in order to function. In fact, if you eat no carbs at all, your body will break down body fat into small molecules called ketones. Ketosis is the process of creating ketones when our body uses primarily fat for energy, which is associated with a carb intake of under 25 grams (under 100 grams is when ketones are first present in the bloodstream and urine). Our bodies not only use fat for energy during ketosis, but may also convert protein (both dietary and muscle) into carbs to be used as fuel.
You may be thinking – “I need to get into a state of ketosis immediately” given the apparent fat burning potential. While you may drop some weight, it may leave you with low energy levels, really bad breath, inability to concentrate as effectively, along with serious vitamin and mineral deficiencies. Furthermore, research studies do not show fat loss is any greater during ketosis versus a diet of equal calories with a lot more carbs. Why be miserable and have the same pace of fat loss?
When it comes to carbs, use your common sense – a few servings of fruit, plenty of veggies (which provide few calories but tons of nutrients), some starch/grains (or a lot if you are very active) each day should help fuel your body and provide the essential nutrients it needs to function optimally.
Hope this helps break the carb questions down into information a bit easier to intake and utilize on your journey into understanding the ins and outs of a healthy lifestyle.