By now, the connection between sleep and weight gain is well established. Numerous studies have provided evidence that sleeping too little — less than five hours — messes with your hormones, slows down your metabolism and reprograms your body to eat more. But a study published in PLOS One quantifies the harm, finding that people in the study who slept an average of six hours each night had waist measurements about 1.2 inches more than those getting nine hours a night. Those with less sleep also weighed more. The study appears to show that waist circumference and BMI are lowest for those with 12 hours of sleep.

Colon cancer risk for overweight teens

Teenagers who were overweight at 17 were at significantly increased risk for developing colon cancer later in adulthood, and those who were obese were at increased risk for rectal cancer as well, according to a new report. The study looked at nearly 2 million young Jewish Israelis who were weighed between 1967 and 2002, before induction to the Israeli army. Their weights were later checked against Israel’s national cancer registry. Obesity is a known risk factor for colon cancer, but earlier studies have reported mixed results about whether being overweight during adolescence confers a risk. The new study used actual weight measurements rather than self-reported ones, said Dr. Gilad Twig, one of the study’s authors and a physician with the Israel Defense Forces.

Walking your dog has health benefits

Just how good is dog walking for you? Older dog owners who walked their dogs at least once a day got 20 percent more physical activity than people without dogs, a British study found, and spent 30 fewer minutes a day being sedentary, on average. All participants tended to be less active on short winter days when it was cold and wet. But regular dog walkers experienced less of a dip in physical activity.