Starving yourself sends your body into famine survival mode, causing you to store extra fat.

Many measures to curb the obesity epidemic are aimed at young children. It's a sensible strategy - we know that overweight children have a good chance of becoming overweight adults. Family homes and schools have accordingly become critical arenas where the battle against the nation's growing waistlines is fought. But there is another equally important environment that can severely affect a person's chances of becoming overweight, but is more often overlooked - the womb.

Anyone who is overweight will testify that losing weight is not as easy as it seems. The people that are lean, or have gone from fat to skinny will say it’s just a matter of motivation and elbow grease.

AMAGASAKI, Japan — Japan, a country not known for its overweight people, has undertaken one of the most ambitious campaigns ever by a nation to slim down its citizenry.

A pill to treat obesity could be available in a decade after a breakthrough in the understanding of how genetic factors make some people much more likely to put on weight.

In this episode, Albert Einstein College of Medicine public health researcher Paul Marantz questions whether dietary guidelines are counterproductive and talks about the philosophy of recommendations based on population studies.

We’ve blogged about obesity at length here at Freakonomics. The health economist Eric Finkelstein has been studying the subject for years, and, along with co-author Laurie Zuckerman, has just published a book, The Fattening of America, which analyzes the causes and consequences of obesity in the U.S. Finkelstein agreed to answer our questions about the book.

Blogs written by fat people — and it’s fine to use the word, they say — have multiplied in recent months, filling a virtual soapbox known as the fatosphere, where bloggers calling for fat acceptance challenge just about everything conventional medical wisdom has to say about obesity.

Obesity is a problem for many American consumers—and now, even our chickens are getting fat!

A study published in the July issue of Economic Inquiry raises that question. With roughly two-thirds of the American population overweight or obese, have our cultural ideals of what we consider “normal weight” changed?