The website was designed to reinforce behaviour such as limiting calories to keep lost pounds off.The website was designed to reinforce behaviour such as limiting calories to keep lost pounds off. (iStock)

People who lose weight are better able to keep it off by consistently checking an interactive website, a new U.S. study suggests.

Researchers evaluated a web-based weight maintenance program involving 348 participants, who recorded their weight at least once a month for 2½ years at a website set up for the study.

Participants were able to maintain an average of nine pounds of their original 19-pound weight loss, compared with five pounds of weight loss among those who checked in regularly for only 14 months.

Weight loss after hip, knee replacements

People who've had a knee or hip replaced may lose weight after the surgery, U.S. doctors have found.

Knee or hip replacement surgery, known as arthroplasty, is on the rise among Canadians aged 45 to 54, according to the Canadian Institute for Health Information.

The U.S. study looked at 196 patients with an average age of 67 who had knee or hip replacement from 2005 to 2007 to relieve pain or disability from osteoarthritis.

Of these, nearly 20 per cent showed clinically significant weight loss of five per cent or more of body weight, the study's lead author, Dr. Michael Bronson, chief of joint replacement surgery at Mount Sinai School of Medicine in New York.

The weight loss indicates a healthier overall lifestyle, Bronson said.

The participants' mean weight of about 175 pounds before surgery fell to about 172 pounds after surgery, doctors found.

In Canada, about 23,000 hip replacements and 38,400 knee replacements were done in 2006-07.

"Participants defined as consistent users of an interactive behavioural website designed to improve maintenance of weight loss had less long-term weight change (less regained), suggesting that internet-based tools can provide some of the accountability and feedback assumed necessary for successful and long-term weight maintenance," said Kristine Funk, a research associate at Kaiser Permanente's Center for Health Research in Portland, Ore.

The study done by Funk and her colleagues was reported Tuesday in the Journal of Medical Internet Research.

"The potential for widespread dissemination at relatively low cost per participant, even when the benefit is modest, makes further development of interactive-technology interventions worthwhile."

The findings are important, since keeping lost weight from coming back often seems to be harder than losing it, Funk said.

According to the Pew Internet & American Life Project, which reports on the impact of the internet on U.S. society, 44 per cent of adults aged 50 to 64 said they used the internet as a source of fitness and exercise information, while 31 per cent reported looking online for information about weight control.

Those participating in the weight loss management study had a body mass index of 25 or higher, where 25 is considered overweight and 30 is considered obese. They also had either high blood pressure or high cholesterol.

The researchers said the website was specially designed for the study to offer support for weight maintenance through five behavioural strategies:

  • Reinforcing existing behavioral self-management such as limiting calories.
  • Encouraging new self-management skills, such as posing questions to nutrition and exercise experts.
  • Improving self-monitoring.
  • Encouraging long-term use of the website by providing innovative content.
  • Promoting social support on an interactive bulletin board.

If study participants didn't enter their weight a least once a week, they were sent emails reminding them to check in.

By the end of the study, 65 per cent of participants were still logging on — a level of participation that the researchers called encouraging compared with shorter-term weight maintenance studies that use the internet.

The U.S. National Institutes of Health funded the study.