Friday, April 29, 2011
Week 14 - Good Carbs, Bad Carbs
With all the talk these days about good carbs and bad carbs, low carbs and no carbs, how is one supposed to sort through so much information and figure out which carbs are actually okay to eat? Pick up any magazine or tune into any talk show and someone is espousing the virtues of eating low or no-carb. Celebrities are shunning carbs, diets promising speedy weight loss warn us to avoid them, and it seems everyone is on some sort of carb-bashing bandwagon. But why all the negative press for carbohydrates? Exactly what is wrong with them and why are so many people eliminating carbs altogether?
To sort it out, we must first understand what a carbohydrate is. Carbohydrates are the body's main source of fuel and are made up of sugars, starches and fiber. Our bodies break down most carbs into single molecules of sugar which can then be absorbed into the bloodstream. Carbohydrates are classified into two main types: simple and complex. Simple carbohydrates are already single or double molecules of sugar and can easily be identified by their "ose" endings -- glucose and fructose (found in fruit), lactose (found in dairy), and sucrose (table sugar which comes from beet or cane sugar). Simple carbohydrates are easily absorbed and contain little, if any, nutritional value other than providing instant energy for the body. Complex carbohydrates are made up of many sugar molecules strung together like a chain. They also contain starch and fiber which are important for good health. Most starches break down into sugar, while fiber is indigestible by humans -- we do not possess the necessary enzymes to break apart the links, therefore it travels through the intestines acting as a "cleanser" for the colon and encouraging the growth of healthy bacteria in the lower gut. Complex carbs require the body to work harder digesting them -- the long chains of sugars must first be broken down into single molecules -- and they contain plenty of other vitamins and nutrients that get absorbed along the way. Complex carbohydrates include grains, vegetables, nuts and seeds, beans and legumes, corn and potatoes.
The reason carbohydrates get such a bad rap is because most Americans eat a diet that is much too high in refined carbohydrates. Refined carbs are foods which have been highly processed by food manufacturers. For example, refined grains have had the high fiber parts (the germ and the bran) removed from the grain. When a complex carb is refined it loses its complex structure and thus all the properties that made it a healthy choice. It takes on the properties of a simple carbohydrate and is processed by the body as such. White rice, white bread, sugary cereals, pasta, noodles and pretty much anything made from white flour, including packaged cookies, crackers and pastries, are all examples of refined carbohydrates. Sodas, sugary beverages and fruit juices are also refined carbs. They are quickly absorbed into the bloodstream causing a rush of glucose which results in excess available energy. Your body uses only the glucose (energy) it needs immediately and stores the rest as fat. Once all the excess glucose is stored in the fat cells, you become hungry again and reach for more simple, refined carbs to satisfy the craving. This cycle repeats over and over. Eating too many refined carbohydrates can result in rapid weight gain.
Unrefined complex carbs are a much better source of energy for your body. Because they are loaded with starches and fiber, it takes your body longer to break them down and move them through the digestive system. There is a slow and steady release of glucose into your bloodstream -- think of unrefined complex carbs as "time-release" capsules -- so you stay full much longer and don't experience rapid hunger and cravings. Small, frequent meals which include complex carbohydrates, along with protein and healthy fats, are the best way to control appetite and supply steady nutrition and energy. Whole grain breads and cereals, fruits, vegetables, brown rice, sweet potatoes and beans are perfect complex choices.
Many popular diets would have you believe that giving up carbs completely is the answer to controlling your weight and appetite. They perpetuate the myth that there is something special, almost magical, about low or no-carb diets. The reality is when you give up an entire food category such as carbs, you eliminate a large number of calories from your diet. There is nothing magical about it: less calories = weight loss. But weight loss at what price? Diets that are too low in carbs deplete the healthy glycogen (the storage form of glucose) in your muscles. Depleted glycogen causes dehydration which results in quick and drastic reductions on the scale. Dieters are often encouraged by these early, large losses assuming it is fat that is melting away. The fact is, the loss is due to water loss and muscle atrophy. We know from our previous Healthy Tip on sarcopenia that a reduction in muscle results in a slowed metabolism. And a slowed metabolism means rapid weight gain when one resumes eating normally again. Studies show that most people cannot maintain a low carb diet for an extended period of time.
When we distinguish between the health-robbing effects of simple sugars and other refined carbs and the health-giving properties of complex carbohydrates, it is easy to see that eliminating all carbs really isn't a good idea (1). They are much too important nutritionally to just write them off. Remember, not all carbs lead to weight gain! Healthy, unrefined carbs are exactly what our bodies need and were designed to digest. They are an important source of vitamins, minerals and fiber that cannot be gotten from any other source. Fruit deserves a special mention -- although it contains simple sugars, it gives a lot of bang for the buck, particularly for those of us with a sweet tooth. It is rich in vital nutrients, high in fiber, relatively low in calories, and provides instant sweetness and hydration. In contrast, overprocessed, refined carbs are nutritionally "empty" and contribute to the obesity epidemic in our country and globally.
As in all the other nutritional Healthy Tips, I encourage you to start paying careful attention to the kinds of foods you are choosing and eating. This week, your task is to keep a list of the foods you eat. Place a star next to carbs that are refined or simple and begin to look for patterns. When you ate a muffin made with enriched flour (simple carb) were you hungry a short while later? Did eating a bagel made from whole wheat or a bowl of oatmeal (complex carbs) keep you satisfied longer? Examine places in your diet where simple, refined carbs can be replaced with wholesome, complex ones. Choose a piece of whole fruit instead of fruit juice, whole grain breads instead of white breads, and oatmeal rather than packaged cold cereals. Choose whole wheat pasta over regular pasta, brown rice over white, and water over sugary beverages and sodas. Try to reduce the number of starred items on your food list. Commit to eliminating as many of the "bad" carbs as you can, enjoy the "good" carbs, and don't feel a bit guilty about eating them! After all, they are your body's preferred source of fuel.