The covers of news magazines were plastered with phrases like "Low-carb Nation" (Time Magazine, May 2004).
This does not mean carbohydrates are no longer important for a healthy lifestyle or that high-carb foods are your best bet for weight management.
Choosing wisely would be simpler if there really were such things as bad carbs and good carbs.
Let's start with the basics: Carbohydrates from produce, grains and milk products are important for a healthy diet.
Sugars and starches supply energy in the form of glucose, the primary energy source for the brain, central nervous system and red blood cells.
The word "carbohydrates" does tell what compounds in this group have in common: They are made of carbon (carbo-) combined with water (-hydrates).
Carbohydrates are usually broken down into three categories: Sugars (or saccharides); starches (also know as polysaccharides); and fibers (polysaccharides that are not digestible).
Sugars can be one sugar unit (mono-saccharides) such as glucose, fructose and galactose; and they can be two sugar units linked together (di-saccharides) such as sucrose, lactose and maltose.
Sugars can be further divided into naturally-occurring sugars (also called intrinsic sugars) and added (or extrinsic) sugars.
Naturally-occurring sugars include those in fruits and vegetables (fructose and others) and in dairy products (lactose).
Most starch is broken down by enzymes into glucose molecules for absorption in the small intestine.
Grains can be further divided into whole grains and refined grains, where the outer layer and bran are removed.
Refined grains contain starches but are generally not good sources of fiber.
Refined grain products are usually enriched with vitamins and minerals, some of which were removed during the refining process.
Legumes: Mostly starch and fiber with some sugars, as well vitamins, minerals and protein.