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Monday, 27 August 2007

C25K W1D2 + Setpoint Theory

Couch to 5K Week One Day Two

Now I know that you are only meant to run three days a week on the Couch to 5K program but I am already marginally fit and Day One was rather easy. That means, of course, that I could still walk this morning.

So it being a BEAUTIFUL day, I headed out the door and ran/walked for 35 minutes. I am planning on doing this session again tomorrow and then moving on to Week Two on Wednesday. I will do Week 2 for three days unless it is too hard and then I will alternate with Week One on the other 3 or 4 days of the week.

If you are thinking of becoming a runner then I recommend this program. There is an awesome free MP3 podcast from Robert Ullrey that talks you through the intervals with cool music. Thanks Robert - the podcasts are fantastic.

Setpoint Theory

I have been reading about the body's "setpoint" and include the following information for your consideration (emphasis is mine).

The setpoint theory holds that if left to its own devices your body, under the dictates of its fat cells, will maintain a certain level of stored fat. When fat levels drop below that amount, your appetite increases and you are constantly bombarded with ''signals'' to eat more and reduce the level of energy you expend. As soon as restraints on food intake are removed (that is, when you get tired of dieting, deprivation and vigilance), the fat you lost is quickly regained.

This is precisely what happened to those who participated in a ''semistarvation'' experiment during World War II. By the time they had lost the fat stored under the skin and in the abdomen, they had also become extremely lethargic as well as irritable and uninterested in work. As soon as the experiment was over, they ate ravenously, quickly regaining all their lost fat.

An interesting series of studies in laboratory rats by Dr. Roy Martin of the University of Georgia suggests that fat cells communicate their needs to the brain through their products, the fatty acids. During weight reduction, fatty acids are used for fuel throughout the body. Although the brain normally does not use fatty acids for energy, Dr. Martin found that during fasting the brain's ''appetite center'' oxidizes fatty acids at a very high rate. This, he believes, signals the brain to stimulate eating.

The second stumbling block to successful dieting also involves the body's attempt to protect itself against the ravages of starvation. The body has a built-in energy-conservation mechanism: When calorie intake drops significantly below the level needed to maintain current weight, the basal metabolic rate drops too. In other words, the body turns down its thermostat and automatically begins to use less energy to run itself.

This mechanism would have served the species well in the early days of agriculture, when many people lived a feast-or-famine existence. Those who, in times of famine, could best hang on to their stored fat lived the longest. And those who were able to stow away extra calories as fat during times of plenty were even further favored. In modern times of perennial plenty, many people seem genetically programmed to remain perennially fat.

As Dr. Martin Katahn, a psychologist who is director of the Weight Management Program at Vanderbilt University, explains in his illuminating and practical new book, ''The 200 Calorie Solution,'' (W.W. Norton, $13.95), this energy-conserving mechanism is the reason many people find that they stop losing weight or lose only very slowly after several weeks on a low-calorie diet.

Whereas before dieting they may have needed 2,000 calories a day to maintain their body weight and could lose a pound of fat a week on a 1,500-calorie diet, after weeks of dieting their reprogrammed metabolism may have slowed down enough to make it impossible for them to lose even another ounce on 1,500 calories a day.

The more drastic the diet, the more drastic your body's countermeasures, Dr. Katahn says. A very low-calorie crash diet can slow body metabolism by as much as 45 percent. When weight is regained after a diet, a disproportionate amount of fat is put in storage so that you actually get fatter each time you fail at dieting.

Furthermore, repeated dieting trains the body to defend itself against starvation by speeding its ability to reduce metabolic needs. So it becomes harder and harder to lose weight by cutting calories.

The bottom line is this: Diets, by themselves, rarely work. Their failure is evidenced by the many millions of Americans who chronically ride the weight-loss/weight-gain seesaw and in the neverending stream of fad diets that occasionally succeed in pushing these people to the ground only to let them ride once more to the top.

Is there any hope? Dr. Bennett, Dr. Katahn and Mr. Gurin think so. Indeed, they have tried their suggestion and found it to work, allowing a slow, steady weight loss that stays lost. The trick, as Dr. Bennett and Mr. Gurin put it, is to lower your setpoint rather that simply resist it. The most practical method for achieving this is exercise.

Evidence for the effect of exercise on weight control spans at least four decades and involves several species, including humans. Basically, it shows that when animals are inactive they spontaneously grow fatter than normal and that as activity increases their weight falls.

Below a certain level of activity - a level commonly found among sedentary Americans, appetite seems to be unleashed from normal controls. When exercise becomes excessive (such as in some longdistance runners), appetite may be unable to keep up with caloric needs. But at a moderate level of activity there seems to be a better balance between appetite and energy expenditure.

One known effect of exercise is a change in body composition: the proportion of the body that is fat diminishes and the proportion of lean muscle tissue increases. Muscle, as Dr. Katahn points out, uses considerably more calories to maintain itself than fat does.

Thus, even if no weight is lost, a well-muscled person can consume considerably more calories without gaining than could a person who weighs the same but has less muscle tissue and more fat. In other words, exercise seems to lower the setpoint, probably by raising the basal metabolic rate and by altering body chemistry so that less fat is put in storage.

Dr. Katahn, who lost 70 pounds and kept them off by following his own advice, recommends adding 200 calories' worth of exercise to your day as the best long-term approach to weight loss and maintenance. This amounts to a 45-minute brisk walk each day or its equivalent in biking, swimming, jogging, tennis, etc. After a year, even with no change in diet, the daily 200 calories of extra expended energy could mean 20 fewer pounds of fat on your body.

He admonishes fat people never to go on a diet to lose weight unless they are willing to change their activity level. ''For a diet to work once and for all,'' he said, ''you must remove the critical contribution of a sedentary life style to your weight problem. Then you will never need to diet again.''


  1. that makes a hell of a lot of sense!

  2. Anonymous11:54 pm

    Great article. Makes total sense