Monday, 22 September 2008

The PhysicsDiet by Richard Muller

Richard Mullers says in this article:-

... Most dieters are so concerned about second-order effects, such as daily fluctuations in weight and changes in metabolism, that they lose track of the first law of thermodynamics: conservation of energy.

Want to lose a pound of fat? You can work it off by hiking to the top of a 2,500-story building. Or by running 60 miles.

Exercise is a very difficult way to lose weight. Here's a rule of thumb: exercise very hard for one hour (swimming, running, or racquetball) and you'll lose about one ounce of fat. Light exercise for an hour (gardening, baseball, or golf) will lose you a third of an ounce. That number is small because fat is a very energy-dense substance: it packs about 4,000 food calories per pound, the same as gasoline, and 15 times as much as in TNT.

There is a much easier way to lose weight, as we can learn from the first law of thermodynamics. Eat less.

A reasonable daily diet for an adult is 2,000 food calories. That's 8.36 megajoules per day, or about 100 joules per second-in other words, 100 watts. Most of that ends up as heat, so you warm a room as much as a bright light bulb. Cut your consumption by 600 calories per day and you'll lose a pound of fat every week. Most diet experts consider that a reasonable goal. Don't drop below 1,000 calories per day, or you might get lethargic. But at 1,400 calories per day, you can easily maintain an active life.

Of course, there is a catch. You'll be hungry.

It's not real hungernot like the painful hunger of starving people in impoverished countries. It's more of a mild ache, or an itch that you mustn't scratch. To be popular, a diet must somehow cope with this hunger. Weight Watchers does it with peer support. The food pyramid does it by encouraging you to eat unlimited celery. Some high-fat diets satisfy all your old cravings-and figure you'll eventually cut back the butter you put on your bacon.

How to cope with the hunger? I attempted to enjoy it. I thought of the movie Lawrence of Arabia, in which T.E. Lawrence says, "The trickis not minding that it hurts." I told myself that the mild ache was only the sensation of evaporating fat. That interpretation has some basis in physics. When you lose weight, most of your fat is converted to the gases carbon dioxide and water vapor, and so you get rid of fat by breathing it out of your body.

... My Zen-like approach to hunger also worked; I found myself declining offers of chocolate cake because I didn't want to lose the sensation of evaporation. I didn't change my level of activity...

A key innovation: I kept up the social aspects of lunch, without eating. I watched others gobbling cheeseburgers, while I sipped diet cola. It really wasn't that hard to do. And the mild afternoon discomfort was compensated by several positive developments. Dinner became truly wonderful. I hadn't had pre-dinner hunger for decades. A sharp appetite turns a meal into a feast. No more cheese "appetizers" for me.

Food is instant gratification. And fast-food chains and gourmet restaurants serve tasty food at remarkably low cost. It is a situation unprecedented in history and unanticipated by our genes. No wonder we are overweight.

Anybody can lose weight. Energy is conserved. Just stop scratching that itch. Of course, you'll have to sacrifice instant gratification. Is it worth it? You decide. Food is delicious and cheap. You might reasonably choose to take advantage of this unique historical circumstance, and decide to be fat.

Based on Richard Muller's arguement that one hour running can lose an ounce of fat this is 4000 calories /16 ozs = 250 calories.

But running typically uses double these calories according to NutriStrategy. eg Running, 5 mph (12 min mile) uses 563 calories per hour if you are 155lbs.

563 calories /4000 calories = 2.25 ozs or 1/8 pound. However the principle is the same - you don't loose much weight from exercising!

Walking the dog at moderate 3.0 mph pace does lose 246 calories per hour (if you are 155 pounds) - which is an ounce an hour.

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