NYTimes: The Calorie-Restriction Experiment

Curtailing calorie intake by 25% wasn't easy in this study. 

Interestingly, the article refers to evidence that we eat a certain * weight* of food each day - our brain isn't satisfied until we've hefted that weight to our jaw, regardless of caloric intake. So the trick these participants taught themselves was to eat low(caloric)-density foods. 

"A number of recent experiments — notably by Barbara Rolls at Penn State — demonstrated that humans tend to eat a consistent weight of food from day to day, but not necessarily a consistent number of calories..."

THE FOOD ISSUE: The Calorie-Restriction Experiment

Eating much, much less helped rats live longer. Will it work on humans?

http://www.nytimes.com/2009/10/11/magazine/11Calories-t.html