A group that is studying the effects of calorie restriction on longevity released a study recently that draws some… interesting conclusions. The article on CNN:
http://www.cnn.com/2007/HEALTH/diet.fitness/01/26/diet.exercise.reut/index.html
Some of the key things I picked up:
I find this very hard to believe. If you’ve got an extra pound of muscle on your body, that muscle needs to burn calories just to stay alive. That’s why I need like 3500 calories a day, just sitting around, and the girl in the cubicle down the hall needs like 2000.
[quote]“It’s all about the calories,” said Dr. Eric Ravussin of the Pennington Biomedical Research Center, part of Louisiana State University in Baton Rouge.
“So long as the energy deficit is the same, body weight, fat weight, and abdominal fat will all decrease in the same way.”
Tests on overweight people show that a calorie is just a calorie, whether lost by dieting or by running, they said.[/quote]
Which is, I suppose, true, except that this doesn’t take into account the metabolic effects of the food we eat.
Here’s the big one though (emphasis mine):
[quote]They tested 24 people, 12 who ate a calorie-restricted diet, and 12 who dieted and also exercised five times a week for six months.
The dieters ate 25 percent less than normal, while the exercisers reduced their calorie intake by 12.5 percent and increased their physical activity to lose an extra 12.5 percent in calories.
An additional 10 volunteers acted as controls. All food was provided by the university in carefully measured portions for most of the study.
The volunteers in both groups lost about 10 percent of their body weight, 24 percent of their fat mass, and 27 percent of their abdominal visceral fat. Visceral fat is packed in between the internal organs and is considered the most dangerous type of fat, linked with heart disease and diabetes.[/quote]
So it’s just as effective, from a weight loss perspective, to cut out 250 calories a day, or to burn an extra 250 calories on a treadmill. What they don’t say is those 250 calories can come either from resisting the urge to eat one half of a Snickers bar, or running for 20 minutes.
Decreasing caloric intake by 10 percent is a lot easier than increasing your caloric expenditure by the same.