In the first experimental study of the effects of daily weighings, David Levitsky, Cornell professor of nutritional sciences and of psychology, and several colleagues, whose study will be published in 2006 in the International Journal of Obesity, weighed a group of first-year female college students at the beginning and end of the semester.
Women who had no further contact with the research team (the control group) gained on average almost 7 pounds in one phase of the study and more than 4 pounds in a second phase of the study.
Women in a "treatment" group, however, did not gain any weight. They weighed themselves every morning and e-mailed their weights to the research team. In turn, the team provided weekly feedback using a method called the Tissue Monitoring System (TMS), a mathematical method for estimating changes in body tissue from a series of daily weight measures. One group of women received weekly graphs and instructions on how to interpret a positive slope as an increase in tissue mass (an early weight gain). A second group received an e-mail indicating how many calories to cut or burn off daily -- either by eating or exercising -- in order to maintain their original weights.
Both methods were equally effective in preventing weight gain.
"TMS appears to be an effective technique to help college freshmen resist gaining weight in an environment that is conducive to weight gain," said Levitsky, who documented the "freshman 15" as a real phenomenon in 2003. "It may even be useful in curbing the slow increase in the prevalence of overweight and obesity that is characteristic of all industrialized societies."
And for those who don't have access to TMS? "The study suggests that plotting your weight daily is all you need to give you a trend over time -- seven days is enough," said Levitsky, noting that although stepping on a scale daily fell into disfavor in the 1970s as an ineffective strategy for controlling weight, several recent reports are reconsidering daily weighing as a useful method to help weight loss and maintenance.
In a related study, Levitsky's research team gave another group of female college freshmen two one-hour lessons on how to estimate appropriate portion sizes in all-you-can-eat dining halls. The result, presented at the July meeting of the Society for the Study of Ingestive Behavior in Pittsburgh, was that the group that received the lessons gained no weight. Yet, the other women -- the untreated controls -- gained more than four pounds in the first 12 weeks of college.
"Preventing weight gain requires knowledge," Levitsky said. "What we're finding is that some knowledge about portion size and regular feedback about people's weight may be enough to people prevent a gradual but typical weight gain that occurs in this country over time."
Levitsky said that more research was needed to determine whether the fact that some women in his studies had to report their daily weights to another person played a role in helping them maintain their weight. He hopes to soon compare women who report their daily weight to another person with women who use a computer program only to monitor their weight.
The study published in the International Journal of Obesity was co-authored by Jessica Garay and Marnie Nausbaum, former Cornell undergraduate students who helped conduct the study as part of their senior honor theses and are now a dietitian and medical school student, respectively; Lori Neighbors, a Cornell doctoral student; and Diane DellaValle, a research dietitian at Cornell.
The studies were supported, in part, by the New York State College of Human Ecology at Cornell.