FRIDAY, Oct. 5 (HealthDay News) -- Severely obese people -- those with at least 100 pounds of excess weight -- are the fastest-growing group of overweight Americans, according to new research.

Analysts examined data from the U.S. Centers for Disease Control and Prevention and found that from 2000 to 2010, the proportion of Americans who were severely obese rose from 3.9 percent to 6.6 percent, an increase of about 70 percent.

The findings mean that more than 15 million U.S. adults are severely obese, with a body-mass index of 40 or more. BMI is a measure of body fat based on height and weight.

But there was some good news. Beginning in 2005, the increasing rate of severely obese people began to slow, according to the investigators at the RAND Corporation, a nonprofit research organization.

"The proportion of people at the high end of the weight scale continues to increase faster than any other group of obese people, despite increased public attention on the risks of obesity," study lead author Roland Sturm, a senior economist at RAND, said in a corporation news release. "But for the first time in the past 20 years, there is evidence the trend is slowing."

Rising rates of severe obesity varied by gender and ethnicity but were present in all groups. The prevalence of severe obesity was about 50 percent higher among women than among men, and about twice as high among blacks than among Hispanics and whites.

For all levels of obesity, the increases over time were highest among people younger than 40.

The study was published online in the International Journal of Obesity.

More information

The U.S. National Heart, Lung, and Blood Institute has more about overweight and obesity.

SATURDAY, Oct. 6 (HealthDay News) -- The really scary thing about Halloween can be the amount of candy that children get and eat.

To ensure a safe and healthy Halloween for kids, here are some tips for parents from Dr. William Gillespie, a pediatrician and chief medical officer at EmblemHealth:

• Give children a healthy snack before they go trick-or-treating so that they'll be less tempted to eat their sweets as they go door-to-door. Make sure your children understand that they can't eat any of their candy until you check to make sure it is safe. Get rid of homemade treats made by strangers.
• Allow your children to pick out a few of their favorite treats to have right after trick-or-treating. Keep the rest of their candy out of sight and allow them only one to two pieces when they ask for it.
• Consider trading a toy or extra allowance for your children's candy. If they are young enough, say the "Candy Fairy" will substitute a toy for the candy if they leave it out for her.
• Be a role model by consuming Halloween treats in moderation yourself. Also, it's a good idea to buy candy at the last minute and get rid of leftovers to avoid temptation.
• Let caregivers such as grandparents and babysitters know the rules on candy, which will prevent children from getting mixed messages.
• Think about giving out non-food treats such as stickers, toys, temporary tattoos, bubbles, small games or colored pencils. If you prefer to give out candy, choose bite-sized ones and hand out dark chocolate (it has antioxidants) or hard candy (it takes longer to eat).

More information

The U.S. Centers for Disease Control and Prevention offers more Halloween health and safety tips.

SUNDAY, Oct. 7 (HealthDay News) -- Even a little exercise can improve the mental health of overweight teens, according to new research.

A Canadian study found a small amount of activity helps these young people with issues such as body dissatisfaction, social alienation and low self-esteem.

"The first thing I tell teens and parents struggling with their weight in my practice is to throw away the scale," Dr. Gary Goldfield, a psychologist and clinical researcher at the Children's Hospital of Eastern Ontario Research Institute, and an associate professor of pediatrics at the University of Ottawa, said in a hospital news release. "These kids face enough challenges with bullying and peer pressure today. This new study is proof positive that even a modest dose of exercise is prescriptive for a mental health boost."

The researchers randomly assigned 30 adolescents, ranging in age from 12 to 17, to either ride a stationary cycle while listening to music of their own choice or play an interactive video game they had picked out for one hour. They completed the activity in a lab at a light to moderate level of intensity. The sessions were repeated twice a week for 10 weeks.

Following their workouts, the adolescents were asked how competent they felt academically, socially and athletically. They also reported on their body image and self-esteem.

Although the two groups of teens had few physical changes over the course of 10 weeks, they thought they were more competent socially and at school, the study revealed. They also felt better about their appearance and weight. The researchers suggested this mental health boost could help overweight teens overcome teasing, discrimination and weight-related bias.

"We're talking about psychological benefits derived from improved fitness resulting from modest amounts of aerobic exercise, not a change in weight or body fat," Goldfield said. "If you can improve your physical activity and fitness even minimally, it can help improve your mental health. By teaching kids to focus on healthy, active lifestyle behaviors, they are focusing on something they can control."

The study was published online Sept. 30 in the Journal of Pediatric Psychology.

More information

Visit the U.S. National Institutes of Health to learn more about exercise and physical fitness.