Imagine gathering 100 people to fill out a survey about health and fitness where one of the questions is "Why do you want to avoid excess weight gain?"

Don't you think "it increases the risk of heart disease" and "it leads to type 2 diabetes" would be two popular answers? Wouldn't "it affects appearance" and "it saps energy" be two others?

Would you expect any one of the 100 to write "it increases the secretion of the hormone cortisol"? Probably not.

Yet the way in which excessive weight gain increases cortisol secretion could very well be why taking off excessive weight is so difficult.

You may know about cortisol in another capacity. A large release of it creates what's called the fight-or-flight response: that immediate rush of energy late at night when you're convinced the noise you just heard is a burglar.

To create that instant energy, your body taps into its most immediate energy source, glycogen which it isn't using in the middle of the night. It also stops burning fatwhich your body generally relies upon for energy during the night.

To escort energy to the muscles and get the muscles to accept it, the body also secretes another hormone, insulin. Insulin, however, tends to do such a thorough job of removing glucose from the blood that it creates low blood sugar which in turn creates the sensation of hunger.

Most people eat when hungry. Unfortunately, obese people secrete significantly more cortisol than people of normal weight not when faced with perceived danger but during a rather run-of-the-mill process that occurs a few times each day.

Eating.

Researchers at Deakin University in Melbourne, Australia checked salivary cortisol amounts after overweight and normal-weight male subjects consumed a meal. They found that when compared to salivary cortisol amounts taken before the meal, the men of normal weight produced and average of 5 percent more.

But the overweight men averaged an increase of 51 percent.

This higher percentage of cortisol secreted creates a greater secretion of insulin. And you just read about and probably remember other entire columns about how increased insulin secretion leads to weight gain.

That's because a large secretion of insulin causes you to eat even after you've consumed a sufficient amount of food.

But that's only one of the two major concerns expressed by the lead author of the study, Anne Turner, Ph.D., senior lecturer at Deakin University.

She said in an article for Medical News Today: "If overweight and obese individuals have an increase in cortisol every time they ingest food, they may [also] be at a greater risk of developing stress-related diseases."

Surprisingly, Turner considers type 2 diabetes to be a stress-related disease, along with cardiovascular disease, anxiety, and depression. She calls the increased secretion of cortisol produced by the overweight and obese "one more reason to shed any excess weight."

What Turner failed to mention is that shedding of excess weight needs to be done properly or the increased production of cortisol does not abate. That's because extreme dieting also increases the release of cortisol.

Proof of this is found in a study lead by Janet Tomiyama, a Robert Wood Johnson foundation scholar at the University of California-San Francisco. Tomiyama assigned 99 women to one of four groups. Two of the four groups consumed only 1,200 calories a day, one didn't diet but counted calories, and one didn't diet or count calories.

By testing the subjects' saliva, the researchers found that the dieters had higher levels of cortisol in their bodies during the three-week study than the non-dieters.

While the dieters still lost an average of two pounds under the tight controls of experimental research, the increase in cortisol suggests that the weight loss for many of the subjects may only be temporary.

Cortisol secretion also compromises the immune system, and while in the short-term increased production tends to help the memory, continued increased secretion hurts it.

The Tomiyama-led study allowed the dieters only 1,200 calories a day even though the average American woman now weighs a bit more than 160 pounds and probably needs at least 2,000 a day to remain at that weight if she's moderately active.

An 800-calorie reduction is too harsh to handle long term.

In the past, I've suggested reducing calories by no more than 250 per day while increasing energy expenditure through additional exercise to burn another 250.

That combination puts you on course to lose about one pound per week, about as much as the body can handle comfortably but not nearly enough, it seems, to please most dieters.

Albeit lesser known, this adverse effect of increased cortisol secretion is just another reason to do all you can to maintain a healthy weight.

And if you're not there and need to lose a few pounds, keep in mind that starvation diets may drop the weight quicker but rarely result in long-term weight loss.