13 March 2008 ~ Comments Off on Low Carb Diets

Low Carb Diets

This trend has been dominating the fitness field for the last few years. Weight loss programs, such as Weight Watchers and Nutrisystem, have based their entire course around controlling these critical macronutrients. But why is there such a fuss over carbs? I will try to answer as many questions as I can about this very complex subject, so stay with me.

Before we advance, I want to make sure that you understand what carbs are. They are our body’s primary source for energy. Carbohydrates come from many different sources – fruits, vegetables, sugary snacks, cereal exc., and all carbs are broken down by the body to form glucose. Glucose is the simplest form of sugar available and serves as our body’s primary energy source. The closer that a carbohydrate is to this form, the faster it is able to be converted into glucose. All carbohydrates contain 4 calories per gram; however, there are two different types of carbs that have very different properties.

Simple Carbs

Simple carbohydrates are the sweet, buzz-causing agents that are primarily found in sugary substances such as candy and soda. They are digested very quickly and are used up very quickly because they are, as the name suggests, simple. It does not take much to convert simple carbs into glucose, and this is the reason why they are considered “bad” carbs. When simple carbs are consumed, you should be active so that you use them up quickly, otherwise, when they are not needed, they convert to fat. Simple carbohydrates kick in really fast, but they also lose their effect after about 30 minutes. After that, they are converted into fat and you are hungry again because your body no longer has fuel to convert to energy.

Complex Carbs

Pastas contain complex carbsComplex carbohydrates are longer-chain carbohydrates that are found in pastas, whole grain foods, vegetables, and fruits. They are high fiber foods that help stabilize your energy levels, and help you to feel satisfied longer after your meal. Do you ever wonder why a 100 calorie apple can leave you feeling satisfied a heck of a lot longer than a 200 calorie candy bar? Because these carbohydrates are more “complex” in their composition, the body takes longer to convert them into glucose. That means that the body no longer thinks that it is lacking resources because it is actively converting fuel. Complex carbohydrates provide a constant supply of energy in the period of a few hours, rather than 30 minutes, and keep your cravings down. See why they are admired so much?

So now we know that the reason why fat compiles on our bodies is mostly the result of simple carbohydrates. How do we know what foods contain what type of carbohydrates?

Glycemic Index

There is a wonderful resource that judges the properties of carbohydrates found in the foods that we eat. This resource is called the Glycemic Index. This index rates carbohydrates based on the effect that they have on our blood glucose levels in a number 1-100. Foods on the lower end of the Glycemic Index are the complex carbohydrates that have a slight spike on our blood sugar levels (this spike is termed an insulin spike). The foods on the higher end digest more rapidly and have a greater insulin spike.

Graph of Simple Carbs vs Complex CarbsThey measure the GI rating of a food by feeding a group of healthy participants a certain product. Then they measure blood samples and construct a blood sugar response curve for a two hour period. They then use a formula to construct a GI rating for each person. Afterward, they find the average GI rating and slap on a GI rating for that food.

So how does this help us? For one, if you are a diabetic, you really need to be aware of the GI content of everything that you eat. For the rest of us, we can modify our diet to minimize high GI foods and maximize those on the lower end. Eating foods lower in the GI will help control appetite and delay hunger. Also, a lot of diseases have a strong correlation to a high GI-based diet. So definitely use this important resource when deciding which foods to eat.

Here are some examples of different foods and their Glycemic Index:

  • Oats – 50
  • Brown Rice – 50
  • Pizza – 60
  • Spaghetti – 65
  • Gatorade – 100
  • Apple – 41
  • Banana – 51

You should try to aim to have an average of 50-55 for all of the foods during the course of a day. This is not as hard to do as you may imagine, there are plenty of good, tasteful, low GI foods to eat.

So, should you just not eat simple carbs? Not exactly and I’ll tell you why.

Simple Carbs Useful?

When you work out, you break down your glycogen levels in your muscles (your muscle’s primary source of fuel). To adapt to this, your muscles recover and build back up a little stronger than before so that that same stress doesn’t deplete you as much. After you workout, your energy supply is low and you need to fill it up again. The faster that you do this, the better and quicker your body will recover.

This is where simple carbohydrates come in. After you workout, you have induced insulin sensitivity. Take advantage of this. Eat or drink something high in the GI. They will convert very quickly and be sent directly to your muscle and fuel storages that you depleted. This gives your body a jumpstart to maintaining homeostasis again. The hormone that sends these nutrients to your muscles is called insulin

You can take advantage of this insulin spike by taking your protein during this critical period. The insulin spike created by the simple sugars will quickly transport your protein to the necessary locations. This is why your post workout meal is very critical to recovery – so never waste your 30 minutes following your workout!

What is an ideal post workout meal? There are many examples of effective post workout meals and shakes available online, but the general guideline is this: .5g/lb of bodyweight of high GI food/drink with .25g/lb of bodyweight of protein (fast absorbing whey is optimum). I even read somewhere that chocolate milk is an excellent post workout alternative, I guess that could be the simplest solution, but I personally like my Gatorade / Protein Shake.

So why? Why are we so sensitive to high GI foods? Why are low carb diets better for us? Why isn’t our body designed so that simple carbs are better for us? The answer lies within our ancestry.


Our Ancestors knew how to eatLong ago, there lived a species of man that roamed the world barefoot, naked and savage. They lived by hunting and gathering food. When they fed, their carbohydrates came from fruits, berries, vegetables and the occasional honey. For 1.6 million years they lived like this. Their digestive system, hormones and enzymes were fundamentally adapted to accommodate a diet high in animal fat, protein, and fiber and relatively low in sugars.

Only for 10,000 years have we enjoyed the food surplus, refined, high GI foods that we enjoy today. Our bodies are not use to having a diet that is so rich in simple sugars. It takes a long time for evolution to take place, and it is pretty apparent that we are not designed to take in massive amounts of simple carbohydrates yet. If you want to read more about this, check out this article.

However, it does not mean that we aren’t adapting to this new lifestyle. There was a New York Times article that suggests that our bodies are producing more of the enzyme that converts starch to simple sugars than people who eat a low starch diet. This could allow us to one day eat the foods that we love to indulge in while remaining fit.

But until then, we should stick to the proven method for maintaining a healthy physical body. Simple carbohydrates have their place, but the majority of a healthy diet should consist of the staples that our ancestor’s left us through their diet – nuts, fruits, vegetables, meat, and fish. If only we were could eat double chocolate ice cream with sprinkles and cookie dough all day long and still build muscle!

I hope that I have cleared up some issues regarding the subject of Carbohydrates. They aren’t so bad you only have to avoid the good ones :P. Don’t think that you can simply eat all that you want as long as it doesn’t have simple carbs though. Remember, if calories in > calories out then you gain weight. It just makes life a lot easier when you aren’t constantly hungry. To prevent this, stick to your complex carbs.

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