Food energy and appetite

          I'm new in this blog business so that I wanted to post some interesting things from the field of physiology.  It is interesting to note that there are more common physiological phenomenon  to most animals than one can ever suspect.  I thought of  some things very common to animals which is the role of food energy on appetite.  From experience, this is hard to explain in simpler terms, and this is a challenge now to me to explain to you this physiological phenomenon.

          Food contains energy, as we know it. It is our fuel especially when we do physical things.  Although food is composed of protein, carbohydrates, fat and some minor things such as vitamins and minerals, these three major nutrients contribute food energy at different proportions. And if we add all these contributions, we have now the total energy contained in the food.  Thus, energy from various sources are additive.  Now, how does this total food energy influence our appetite?  If appetite is loosely defined as the amount of food eaten to ones satisfaction, then this amount depends on the energy content of your meal relative per unit weight.  So if the food contains 100 kilocal per gram and your appetite is up to 3000 kcal (this example is hypothetical), then it will take 3000/100 grams or 30 grams to satisfy your appetite.  Thus, the higher the energy content of the food per gram, the lower is the amount of food that you will have to eat to reach satiety.  An application of this phenomenon can be seen when you eat in an eat-all-you-can restaurant.  If you eat mostly energy-dense diet such as roasted pork, beef with so much fat in it (because fat has the highest energy density than either carbs or protein), then you will reach satiety very shortly or after a few servings.  On the other hand, if you choose less energy-dense meal such as vegetable salad or any meal which incorporated plant materials, you will eat a more substantial amount for you to reach satiety.  But there is a physical limit to eating mostly salad and this is the distension of the stomach.  Regardless of this, you will have eaten more if you eat less energy-dense diet.

          The application in animal husbandry is much more appreciated especially if the feed is pelletized such as those fed to fish, pigs, poultry etc.  Feed formulation  should consider the optimum energy density of the formulation such that when satiety is reached, the animal should have consumed a balanced of all essential nutrients in  the diet.  This makes rasing these animals profitable by optimizing the amount of food given to produce a certain amount of growth (in terms of weight perhaps).  Thus, we could say that energy content of food influences appetite.