I am a diabetic on insulin and have discovered that the only way to control my blood sugar is by taking an educated guess at the amount of calories that I am eating and inject my insulin accordingly. This has led me to not only learn about the difference in calories depending on the way that the food is prepared but has also taught me the value of each food in calories. For example knowing the calories in rice is something that I learnt many years ago in order to make a reasonably accurate decision about the total amount of calories on my plate. Obviously I have continued to learn over the years and there is always something new that I can find out about hiding calories by simply cooking food differently. But the most important part is knowing what the cooked value of a food is and knowing how it was cooked because it can make a huge difference in the amount of insulin that I give myself.