Monday, March 02, 2009

Debunking the zero-carb myth

Whenever I'm dieting down for a bodybuilding contest, I'm constantly asked about my diet. What I eat. When I eat. How I prepare my meals. Many times, when I give the chicken & sweet potatoes answer, I get this response: "Sweet potatoes? But those are carbs. I thought you can't eat carbs."

And there it is, the great carbohydrate myth. Thanks to the Adkins diet and many others, carbohydrates have been stigmatized as the evil, anti-weight-loss macronutrient. Not only is that an unfair label; it’s completely untrue. Carbohydrates are important for many body functions including energy transport and storage, blood clotting, proper immune system function and brain operation (read: the brain and neurons cannot burn fat and need glucose – carbs – for energy). While, yes, the body can survive on a lack of carbohydrates for short periods of time, I wouldn’t recommend it as part of an overall healthy lifestyle regimen. Not only does a lack of carbs lead to a decrease in organ function – the liver being another major organ affected by low-carb diets – but also results in increased fatigue, and the accompanying reduced fiber intake leads to gastro-intestinal distress & irregularity.

So, why are sugary foods so unhealthy? It’s not because of the amount of carbohydrates they contain, but it’s the types of carbs present in certain foods. In order to make educated decisions about which carbs to consumer during your weight-loss cycle, it’s important to pay attention to the glycemic index. The glycemic index is a measure of the effects of carbohydrates on blood glucose levels. Carbohydrates that break down rapidly during digestion releasing glucose rapidly into the bloodstream have a high GI. Carbohydrates that break down slowly, releasing glucose gradually into the bloodstream, have a low GI. For most people, foods with a low GI have significant health benefits. A lower glycemic index suggests slower rates of digestion and absorption of the foods' carbohydrates and may also indicate greater extraction from the liver and periphery of the products of carbohydrate digestion. A lower glycemic response is often thought to equate to a lower insulin demand, better long-term blood glucose control and a reduction in blood lipids. The insulin index may therefore also be useful as it provides a direct measure of the insulin response to a food. A low GI food will release glucose more slowly and steadily. A high GI food causes a more rapid rise in blood glucose levels and is suitable for energy recovery. So, when beginning and maintaining a weight-loss cycle, choose foods that rank low on the glycemic index.

Here’s a link to a chart showing the glycemic index of many popular foods.

"Wait a minute," you might say. "Sweet potatoes have a GI of 54. I thought you said they were a good source of the right carbs." Well, here’s where you have to weight your options. During my contest-prep cycle, I’m still consuming about 250 grams of carbohydrates per day (you’ll most likely want to consume about 1/6th of that amount). If I wanted to use, say, peppers or broccoli to get those 250g of carbs, I’d have to eat 10-times the weight of those veggies as do with sweet potatoes – not very practical. So, I have to determine the intersection between quantity and glycemic index. Plus, I'm burning so much energy on a daily basis that the carbs I'm taking in can be higher on the index since I'll need them to fuel recovery. So, another guideline is, the more physical energy you're exerting on a daily basis, the higher the glycemic rating of the carbs your consuming can be.

Another great way to maximize your carb intake for proper weight loss is the carb-cycling method, which is described here.

1 comment:

Lisa Creech Bledsoe said...

Nicely done. You've taught me some interesting stuff.

I shift (but don't eliminate) my carb intake to control weight, but I typically try to simply stick with foods with a low density of carbs. In the end, this just means I eat a lot more of the healthiest veggies and fruits and less white bread/rice/pasta. I combine that with a general one-third/two-thirds rule of thumb, which means I try to eat one-third lean protein and two-thirds low-d carb sources at every meal or snack. I think that came from reading The Zone. Anyway, it works for me.

That is all the tweaking I need to do most of the time; you have much more ambitious goals and your careful attention to detail is showing. Good on ya, mate.