Obesity means that there is too much body fat. All human animals need some amount of fat for storing energy, keeping the body warm, metabolizing certain vitamins, and many other functions. The healthy percentage of body fat for men is between 18% and 23%; for women, it should be between 25 and 30%. Percentages beyond these limits earns us a diagnosis of overweight or obesity.

Obesity is a national epidemic, meaning it is widespread, out of control, and there is no end in sight. So, what's going on? What has happened in the past few decades to account for the fact that two-thirds of adults and at least half of our children are overweight?

Look at the 5 most typical causes of obesity:

1. Sleep deprivation. We are a nation of “busy bees”. Who has time to sleep anyway? Right? Wrong! The hormone “leptin” regulates perceptions of hunger. It is produced during sleep. If we have an inadequate amount of leptin in our bloodstream we are likely to feel hungry more frequently (the fact that if we're up late at night we're probably “grazing” which does not help the matter either).

2. Stress. We're a nation of stressed out “busy bees”! “Cortisol” is another hormone which comes into play in times of stress. Stress is likely to put us in an internal state of survival mode which tells us us a crisis is coming and we'd better fuel up for it (also, the types of foods we usually reach during stress are “comfort foods” which are typically high calorie, high fat).

3. Time pressure. Many of us feel “behind” from the time we get up in the morning until we go to bed. Who has time to cook? Fast food restaurants with their high fat, high sodium, high calorie, high sugar offers.

4. Medications. Some of the drugs which are commonly taken during the times in which we live are also associated with possible weight gain. Antidepressants, anti-inflammatory agents such as steroids, drugs for mood disorders and diabetes, along with many other classes may be at the bottom of weight gain.

5. Hormonal conditions. Some underlying medical conditions may contribute to weight gain. Anything that interferees with hormone regulation, such as low thyroid function, menopause, adrenal disorders, and polycystic ovarian disease can cause weight gain.

What can be done? First of all, if you suspect your medication may be cause for weight gain, do NOT, under any circumstances, stop taking the medication without your doctor's approval. If you do, you may be putting yourself at great peril. Even if your doctor agreements that you can stop the meds, many drugs (such as cortisone) require weaning off of them, rather than stopping them abruptly. Also, some drugs have acceptable substitutes which may not have the same effect on your weight.