Carbs - A Popular Topic for Weight Watchers
~ May 2005 No.192 ~
It seems like everyone these days is talking about carbs or, more correctly, carbohydrates. In any introductory nutrition course, you learn that our foods are made up of a mixture of five families of nutrients: protein, fat (sometimes called lipid), vitamins, minerals and carbohydrates. Some fatty acids (lipids), some minerals and some amino acids that make up protein are essential.
Carbohydrates, as the name implies, are made up of carbon, oxygen and hydrogen molecules. This combination of only three types of atoms can result in many thousands of different compounds in nature. Carbohydrates can be found in every living thing. Some carbohydrates are relatively small in size - the simple sugars for example, while others are in the form of polysaccharides which are long chains of sugars linked together.
In the body, carbohydrates can act as energy sources, but they are also the building blocks of many cellular structures.
The simple sugars refer to compounds such as glucose, fructose, lactose, galactose and mannose. Two simple sugars bonded together form diglycerides. Common table sugar is a diglyceride containing glucose and fructose.
One of the principles behind the Atkins diet is that the body uses two types of fuel - fat or carbohydrate. When people eat a non-Atkins diet their body has large stores of carbohydrates in the form of glycogen in the liver and elsewhere. When they need energy, this stored carbohydrate in easily mobilized, and so the body does not need to use any of its stored fat. The glycogen reserves are quickly replenished and so, even if you exercise, you do not burn off any of your fat reserves. By eating a diet low in carbohydrates, glycogen stores are low, and so when energy is needed, fat deposits are used. You exercise and you get slimmer.
During moderate exercise the glycogen in the liver is used to generate energy. Unless you exercise for 20 minutes or more the body does not start using fat for energy.
The most common carbohydrate in our food is starch. Starch is a very large chemical compound made up of glucose molecules. Depending on how the glucose rings are bonded together, the starch can have different properties. As starch passes down our gastrointestinal tract digestive enzymes break down the starch into glucose which is then absorbed. Starchy foods in our diets include potatoes, rice and grains.
Carbohydrates have about half the calories per gram than does fat. So when the word went out that we should cut down on fat in our diet, pasta bars became very popular. However, many weight watchers forgot that a heaping plate of pasta with even a bit of salad or other fat based dressing had more calories than the fat they were trying to avoid. So in many cases people soon became disenchanted with the move to a high carbohydrate diet..
- Read more about carbohydrates and physical activity
- The Physician and Sportsmedicine: Carbohydrate Unloading: A Reality Check
March 08 2016