Choosing low calorie, nutrient dense foods Calories aside, different groups of foods serve different uses in the body. Within each food group, different foodstuff also behaves differently. An example is carbohydrates. Initially touted as being less fattening than fat, and then labeled as the obesity culprit, further research has separated carbohydrates into 'good' and 'bad' ones.
The Glycemic Index was developed to describe the digestion of carbohydrates and the absorption of the sugar into the blood stream. Foods with higher GI are digested more rapidly than foods with lower GI, leading to a higher rate of increase in blood sugar levels.

Apart from the three main food groups, our body also needs a balance of vitamins and minerals. Phyto-nutrients, many of them anti-oxidants, have also been discovered to have numerous crucial health benefits. Taking in a variety of foods will maintain a healthy metabolism and functioning of the different body systems. Thus, a scientific nutrition plan should encourage and educate patients in order to motivate them to maintain healthy weight in the long run.