Normal weight adults, including those who had lost a lot of weight and kept it off, ate more often than overweight people in a new study looking at factors that may help prevent weight gain.
Researchers following about 250 people for a year found that overweight individuals ate fewer snacks in addition to meals than people in the normal body weight range, but the overweight still took in more calories and were less active during the course of the day.
"Most of the research has shown that people who eat more frequently have a lower weight," said lead researcher Jessica Bachman, assistant professor in the Department of Nutrition and Dietetics at Marywood University in Scranton, Pennsylvania. "But no one knows why."
In particular, Dr Bachman said, she wanted to understand what people who have lost significant amounts of weight do to maintain their weight loss, as a first step to helping guide others in losing weight and keeping it off.
She and her team analysed data collected in two large studies sponsored by the National Institutes of Health. One looked at the eating habits of people with a body mass index between 25 and 47 (i.e., overweight to obese).
The other study looked at adult men and women of normal weight (BMI of 19-24.9), about half of whom had lost at least 30 pounds and maintained their weight loss for more than five years.
The researchers found that on average the normal weight subjects ate three meals and a little over two snacks each day, whereas the overweight group averaged three meals and just over one snack a day.
Generally, though, "weight loss maintainers" consumed the fewest kilo joules, at about 7560 a day, compared with the normal weight and overweight subjects, who took in 7980 and more than 28400 kilo joules a day, respectively.
Weight loss maintainers also were the most physically active of the three groups, Dr Bachman said, burning off about 3360 kilo joules a week through exercise and other activities, compared to 8400 kilo joules a week among the normal weight subjects and 3360 kilo joules a week in the overweight group.
The results, published this month in the Journal of the American Dietetic Association, suggest that weight loss maintainers intentionally do more to keep from regaining extra pounds, Dr Bachman said.
"It appears that being extremely physically active and eating more often helps them keep the weight off," she said. "Most commonly, they were walking at least 60 minutes a day seven days a week."
Dr Bachman believes her study is the first to compare eating frequencies among successful weight loss maintainers, other normal weight people and those who are overweight.
She speculates that snacking might help prevent weight gain by staving off intense hunger.
"If you eat more often, it stops you from getting too hungry," she said. "If you wait 10 hours after you've last eaten, you end up eating a lot more food. If you sit down and you're really hungry, you also tend to eat more calories."
More research is needed, Dr Bachman added, because the reasons that eating more often tends to be associated with having a lower BMI are still unclear.
"This is kind of research as a baseline, and from there we can develop some hypotheses," Dr Bachman said. "Weight loss maintainers are a new group that really is starting to get a lot of attention. The idea is to find out what they are doing, and get other people to do the same thing."
(Reuters Health, Kimberly Hayes Taylor, November 2011)