Simple carbs are composed of either a single sugar molecule (monosaccharides) or two sugar molecules (disaccharides). The most common monosaccharides are fructose and glucose. Fructose is derived from food, while fructose comes from fruit. Disaccharides are formed from the combination of two monosaccharide molecules. Table sugar is an example of a disaccharide.

The body digests simple carbs quickly, leading to a rapid spike in blood sugar levels. Eating simple carbs by themselves, enhances this effect. In turn a large amount of insulin is released into the pancreas. The insulin in turn removes the blood sugar from the blood stream. The effect on the body is reduced energy, weakness, mood swings and hunger. This hunger leads to repeat cycle of simple carb intake and the whole process starts over again.

The most common forms of simple carb are white sugar and white flour.