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Health Research
Agnus Alexander | agnusalexander122

The New Diet Math

Jan 2nd 2014 at 9:39 PM

I’ve written before about the importance of doing the diet math for controlling our weight. At the recent annual meeting of the American Association for the Advancement of Science, Dr. Carson C. Chow, Ph.D., an MIT-trained mathematician and physicist, discussed his new math of obesity with his presentation, “Illuminating the Obesity Epidemic With Mathematics.”

Not surprisingly, his new math is very much like the old math, with a little addition here and a little subtraction there. Rather than calories consumed versus calories utilized, his simple formula looks like this:

Chow became interested in applying mathematics to hopefully solve the obesity epidemic when he joined the National Institute of Diabetes and Digestive and Kidney Diseases, a branch of the National Institutes of Health.

“I could see the facts on the epidemic were quite astounding,” said Chow. “Between 1975 and 2005, the average weight of Americans had increased by about 20 pounds. Since the 1970s, the national obesity rate had jumped from around 20 percent to over 30 percent. The interesting question posed to me when I was hired was, ‘Why is this happening?’”
So, Why is This Happening?

Chow’s math has supported the belief that the obesity epidemic has been caused by the overproduction of food in the United States. Beginning in the 1970s, there was a change in national agricultural policy. Farmers were encouraged to grow as much food as they could and farms became much more productive. The costs of food decreased, while the number of calories available to the average American grew by about 1,000 a day.

“What do people do when there is extra food around?” Chow asked knowingly, then answered, “They eat it!”

Most zoologists know that the size of a population is determined by the available food supply. With humans, not only the numbers, but the size of the individuals are also driven by the food supply. Population does not determine how much food there is; instead, how much food there is determines the population. We are under the laws of nature as much as any other species. We have become reluctant prisoners of our biology.

“With such a huge food supply, food marketing got better and restaurants got cheaper,” continued Chow. “The low cost of food fueled the growth of the fast-food industry. If food were expensive, you couldn’t have fast food.”

Chow now feels that the old math — in which a 3,500-calorie deficit is what it takes to lose a pound of fat weight — needed to be modified. “The body changes as you lose,” he explained. “We also found that the fatter you get, the easier it is to gain weight. An extra 10 calories a day puts more weight onto an obese person than on a thinner one.”

Many of us who have tried to lose weight know how difficult it can be. The classical math of energy balance states that one pound of fat contains about 3500 calories. This part of the classical diet math is correct. The problem arises, suggests Chow, when we use this math of energy balance and extrapolate it to weight loss. For example, according to this concept, if you want to lose a pound of fat, you need to reduce your daily calorie intake by 100 calories and in 35 days (35 x 100 = 3,500) you should have lost that pound. Doing this over a year, you should have lost about 11 pounds. This is not what typically happens because it does not take into account how the body adapts to weight loss by a reduction in basal metabolic rate.

In addition, Chow found that as we reduce our caloric intake, our body reaches an equilibrium. He discovered it takes about three years for a dieter to reach his or her new stabilized weight: “Our model predicts that if you eat 100 calories fewer a day, in three years you will, on average, lose 10 pounds — if you don’t cheat.”

He also found that huge variations in your daily food intake will not cause variations in weight, as long as your average food intake over a year is about the same. He claims that this is because a person’s body responds slowly to our food intake.
What About Genetics or Lack of Physical Activity?

Chow acknowledges that people often think that the obesity epidemic has to be caused by genetics or lack of physical activity, even though studies demonstrate that levels of physical activity have not really changed in the past 30 years. He admits that although there are people who may have a genetic disposition to obesity, if they live in societies where there isn’t a lot of food, these individuals do not get obese. Therefore, he still maintains that it is the excessive food supply that is the problem.
Diets and Dieting

“One of the things the numbers have shown us is that weight change, up or down, takes a very, very long time. All diets work. But the reaction time is really slow: on the order of a year,” stated Chow.

He feels that people don’t wait long enough to see what weight they are going to stabilize at. Because of this, if we lose weight and then return to our old eating habits, the tendency is to return to at least our original weight within three years.
The Bodyweight Simulator

Chow and his associates have developed a Bodyweight Simulator to help facilitate the diet math. With this, people can plug in their information and learn how much they’ll need to reduce their food intake, increase their activity level, and how much time it will take to reach their weight loss goal.

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