According to Ayurveda, the real essence of a food item is not based only on the chemical composition, nutritional content or the calorie count.
The first parameter is the easy digestion of the food. If the stomach or intestine is not able to digest the food properly then all the nutritional value will go to waste. The factors responsible for easy digestion are 1) Temperature 2) particle size 3) amount of digestive juices required to burn the food. Therefore food which is freshly cooked or warm with smallest particle size (liquid or powder) and in right quality and quantity is the best food. No doubt milk is one of the best foods.
Second most important factor is easy absorption of food. There are various methods of absorption in the intestines. Diffusion is the easiest method; other types of absorption might require active effort by the body. Therefore the food that can easily diffuse the nutrition in the intestine is the best food. Otherwise we might spend 2.5 calories to gain 3 calories which is overall not the most profitable deal.
According to Ayurveda, raw form takes the longest to digest. Different types of food preparations and their absorption efficacy is as discussed in the following link :