In 1972, Dr. Robert Atkins first published his book, Dr. Atkins New Diet Revolution, which suggested a new way to diet. Up until this time, dieting pretty much consisted of lowering the number of calories eaten per day or lowering both the amount of fats and carbohydrates eaten. But with a totally new approach, Dr. Atkins' diet was strictly focused on limiting carbohydrate consumption. Since then, a number of low-carb plans have come and gone and even come back again. Face it, low-carbing has been around for more than thirty years -- and given the daily barrage of new products, menus, diet plans and recipe books out there, it could easily be popular for another thirty. So, by now you're probably wondering "What are carbohydrates, exactly and how can restricting my consumption of them help me lose weight?"
There's a strong chance that you've heard of "carbohydrates" and "complex carbohydrates." They come in many forms including rice, pasta, bread, crackers, cereal, fruits and vegetables. Carbohydrates provide your body with its basic fuel. You can think about the relationship between your body and carbohydrates in much the same way you would consider the relationship between a car engine and gasoline.
The simplest carbohydrate is glucose. Glucose, also called "blood sugar" and "dextrose," flows in the bloodstream so that it is available to every cell in your body. Your cells absorb glucose and convert it into energy to drive the cell.
The word "carbohydrate" comes from the fact that glucose is made up of carbon and water. The chemical formula for glucose is:
You can see that glucose is made of six carbon atoms (carbo...) and the elements of six water molecules (...hydrate). Glucose is a simple sugar, meaning that to our tongues it tastes sweet. There are other simple sugars that you have probably heard of:
Glucose, fructose and galactose are referred to as monosaccharides. Lactose, sucrose and maltose are called disaccharides (they contain two monosaccharides). Monosaccharides and disaccharides are called simple carbohydrates. When you look at a "Nutrition Facts" label on a food package and see "Sugars" under the "Carbohydrates" section of the label, these simple sugars are what the label is talking about.
There are also complex carbohydrates, commonly known as "starches." A complex carbohydrate is made up of chains of glucose molecules. Starches are the way plants store energy -- plants produce glucose and chain the glucose molecules together to form starch. Most grains (wheat, corn, oats, rice) and things like potatoes and plantains are high in starch. Your digestive system breaks a complex carbohydrate (starch) back down into its component glucose molecules so that the glucose can enter your bloodstream. It takes a lot longer to break down a starch, however. If you drink a can of soda full of sugar, glucose will enter the bloodstream at a rate of something like 30 calories per minute. A complex carbohydrate is digested more slowly, so glucose enters the bloodstream at a rate of only 2 calories per minute (reference). Complex carbs can be either high in fiber such as broccoli or low in fiber such as bananas or potatoes.
Carbohydrates are not the only substances the body uses for energy. The body also uses proteins and fats for fuel. Protein is contained in foods like red meat, poultry fish and cheese. Fats are also an important part of our diet. Many foods contain fat in different amounts. High-fat foods include dairy products like butter and cream as well as mayonnaise and oils. The idea behind low-carbohydrate dieting is to restrict the amount of carbs you eat and increase your consumption of protein, good carbs (like high-fiber vegetables) and sometimes fat.