Have you ever watched someone who appears thin and healthy eating a piece of chocolate cake and wondered how they stay thin? Part of the reason is that they have a set-point in their brain that keeps their body fat and weight from varying~ that is, until they do something that causes the brain to change its settings for weight control.

That's what happened to me when I quit smoking. I'd been slender all my life until I stopped smoking and gained nearly 25 pounds! Quitting nicotine had triggered a chemical process that altered a weight control function in my brain. My body began to create fat out of what I ate, where it used to eliminate any excess calories. (To quit smoking is only one of many events that can trigger a change in the weight controls of a person's brain.)

Let's call the weight regulator in your brain a *set- point,* and a good image for the set-point is the temperature you set on the thermostat for the heating and cooling system of your house. If it is set at 71 degrees, then the temperature doesn't vary by more than a degree or two before the thermostat tells the furnace to heat up (or the air conditioner to cool down).

Your brain's set-point functions similarly, maintaining a consistent weight and fat level through interactions of hormones, etc. Exploring the body's chemistry is beyond this article's scope. It's sufficient to understand that if your weight has increased (or decreased), it's because the set-point in your brain changed. And so, if you prefer to lose (or re-gain) that weight, specific habits are necessary to adjust the set-point to your desired level.

One. Eat the right things. This is not difficult, if you follow these clear guidelines: a) Keep refined carbohydrates to a minimum. That is, avoid foods made with sugar or flour. b) Eat less fat, but that doesn't mean to use products labeled 'low-fat' such as low-fat mayonnaise. Producers have to use so many chemicals to make low-fat, processed foods taste OK that you're better off just eating the real thing - only less of it. Also, eat less animal fat, like cheese, butter and marbled meat. c) Eat complex carbohydrates: whole grains, vegetables and fruits. Your body recognizes these as normal foods, so it will process them to give you energy now, instead of giving you stored energy (fat).

Two: Drink water. It is necessary to your metabolism and helps your body eliminate toxins and other excesses. Sweetened juice, coffee, tea, diet or regular soda, and alcohol don't contribute to good metabolism or health. Keep use of them minimal, if at all.

Third, do the right kind of rhythmic large muscle exercise daily, and sustain it for 30 to 60 minutes. If this sounds like a lot of time, ask yourself, how important is it to you to be healthy and/or lose weight? You're not going to re-set your brain's weight regulator (the set-point) without exercise - it's that simple. But the exercise can be a pleasure once you understand which types to do. Fortunately, your not faced here with push-ups or lifting weights.

For exercise that will adjust the set-point, 'large muscle' means in particular to use your legs. Walking is the ideal exercise to begin with; you don't need special gear or equipment. You could also swim, bike, or jog. Do something you can enjoy. 'Rhythmic' refers to exercise you do steadily, repetitively. 'Sustained' means continuous - no stopping. The minimum is 30 minutes a day. For quickest results, an hour daily is better. Your heart rate should be at a level where you exert yourself, but can still have a conversation. Go much higher than that level, and you're no longer doing set-point changing exercise. In this case, 'no pain-no gain' is undesirable.

If you make these three things a daily habit, (proper eating, drinking, and exercise) your set-point will change, and you'll lose weight. I lost the 25 pounds I'd gained when I stopped smoking, and in the process I learned some pleasant habits that have improved the quality of my life as well as my health. Habitually, I eat delicious whole foods, enjoy a daily walk, and drink mainly water. I feel good now, and looking good is just a bonus. You'll feel good, too, and your body will thank you, blessing you with good health.

Please note: This article is for information purposes only. Always consult your doctor or health-care professional.

Serena Harstad has written extensively on nutrition, fitness and health topics for All About Nutrition, the best on-line nutrition information resource. Visit: http://aanutrition.com for additional articles by Serena Harstad