Depression is one of the most universal of all human emotions. No one can expect to go through life without experiencing depressions. A depression brought about by sad events, failures, or financial reverses (and thus one which is entirely understandable) is sometimes referred to as a reactive depression. It is not always possible to identify the causes of depressions, however. Some seem to arise almost spontaneously from within; to put it another way, the events that trigger them seem to be insufficient causes. Some of the depressions that are seen in middle-aged individuals fall into this category and are sometimes referred to as endogenous depressions.
The weight of the body is also related to the action of the thyroid gland, which has a part in determining the basal metabolism. Fever will increase the metabolic rate. Excess action of the thyroid will also give a rate over on the plus side whereas deficient action of the thyroid moves the rate to the minus side.
Great numbers of people believe that most diseases come from wrong food. As a result innumerable dietary fads and fancies attract them. Really, the body is a chemical plant which manufactures some of the substances it absolutely must have to survive. Fundamental mineral substances cannot be manufactured by the body. Vitamins cannot be manufactured by the body and must be taken in food or otherwise, since the body depends on them for health and growth.
Dietary deficiencies naturally occur most often among people who get insufficient food but also among those who get the wrong foods. The most common dietary disorder is overweight or obesity.