Body weight simulator

*bump*

Thank you so much for sharing!

bump.
I'll check it out.

Checking it out later...thanks! )

Thanks for sharing :-)

bump

Bump, thanks for the info.

The mathematician who helped develop this simulator discussed the model and weight loss trends in the United States with The New York Times.

http://www.nytimes.com/2012/05/15/science/a-mathematical-challenge-to-obesity.html?ref=us

A CONVERSATION WITH CARSON CHOW
A Mathematical Challenge to Obesity


"What new information did your equation render?

That the conventional wisdom of 3,500 calories less is what it takes to lose a pound of weight is wrong. The body changes as you lose. Interestingly, 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.

Also, there’s a time constant that’s an important factor in weight loss. That’s because if you reduce your caloric intake, after a while, your body reaches equilibrium. It actually takes about three years for a dieter to reach their new “steady state.” 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.

Another finding: 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. This is because a person’s body will respond slowly to the food intake.

Did you ever solve the question posed to you when you were first hired — what caused the obesity epidemic?

We think so. And it’s something very simple, very obvious, something that few want to hear: The epidemic was caused by the overproduction of food in the United States.

Beginning in the 1970s, there was a change in national agricultural policy. Instead of the government paying farmers not to engage in full production, as was the practice, they were encouraged to grow as much food as they could. At the same time, technological changes and the “green revolution” made our farms much more productive. The price of food plummeted, while the number of calories available to the average American grew by about 1,000 a day.

Well, what do people do when there is extra food around? They eat it! This, of course, is a tremendously controversial idea. However, the model shows that increase in food more than explains the increase in weight.

In the 1950s, when I was growing up, people rarely ate out. Today, Americans dine out — with these large restaurant portions and oil-saturated foods — about five times a week.

Right. Society has changed a lot. With such a huge food supply, food marketing got better and restaurants got cheaper. The low cost of food fueled the growth of the fast-food industry. If food were expensive, you couldn’t have fast food.

People think that the epidemic has to be caused by genetics or that physical activity has gone down. Yet levels of physical activity have not really changed in the past 30 years. As for the genetic argument, yes, there are people who are genetically disposed to obesity, but if they live in societies where there isn’t a lot of food, they don’t get obese. For them, and for us, it’s supply that’s the issue.

Interestingly, we saw that Americans are wasting food at a progressively increasing rate. If Americans were to eat all the food that’s available, we’d be even more obese.

Any practical advice from your number crunching?

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.

People don’t wait long enough to see what they are going to stabilize at. So if you drop weight and return to your old eating habits, the time it takes to crawl back to your old weight is something like three years. "