Obesity is a complex problem that scientists are still struggling to understand. In some cases, genetics seem responsible; in others, various combinations of hormonal, metabolic, and behavioral factors appear to play a role. But in most cases, it's hard to determine the exact cause of obesity.

It's difficult enough for a doctor to figure out why an individual patient has accumulated excess body fat. But what accounts for a worldwide epidemic of obesity? It's hard to understand how human genetics, hormone levels, or metabolic activity could change rapidly and simultaneously in millions of people, yet obesity has been increasing sharply ...

I do my best to exercise every day, either walking two miles in good weather or riding my exercise bike for 30 minutes on wet or cold days. Should I keep going when I catch a cold, or would I be better off resting?

When I awaken in the morning, I have terrible bad breath. My breath seems okay during the rest of the day, but I worry about developing halitosis. What causes bad breath?

The day before the findings were even released, The New York Times reported on the long-awaited United States Preventive Services Task Force (USPSTF) recommendation on prostate-specific antigen (PSA) testing. The headline announced "U.S. Panel Says No to Prostate Screening for Healthy Men." The public response was immediate, ranging from approval to confusion and even outrage; the CEO of a prominent prostate cancer advocacy group proclaimed that the USPSTF position "condemns tens of thousands of men to die this year and every year going forward."

Now that the report is available to all of us and we've had time to study ...

A good night's sleep is remarkably powerful. It restores mind and body, preparing both for the challenges that lie ahead. Without restful sleep, mood, concentration, and mental performance suffer. Sleep deprivation is a major cause of car crashes and other accidents, and it has been linked to important medical problems ranging from hypertension, obesity, and diabetes to heart disease, erectile dysfunction, and possibly even prostate cancer.

Health-conscious men don't take sleep for granted, and scientists don't either. In fact, research suggests that even a brief nap may help boost learning, memory, and creative problem solving — all while your head ...