The logging "forces you to be aware of the connection between your eating and your weight," David Levitsky, the paper's senior author and a professor of nutrition and psychology at Cornell, said in a statement explaining the conclusions of the study. "It used to be taught that you shouldn't weigh yourself daily, and this is just the reverse."
Published in the Journal of Obesity, the research study is small. There were only 162 individuals, a self-selected group that wanted to lose weight, and they were allowed to choose any weight loss method, including reducing portion size or skipping meals.
The most significant finding isn't how much weight the participants lost (it was small), but how long they kept the pounds off. Studies have shown that 40 percent of weight lost comes back within a year and 100 percent in five years.
In contrast, one year after the weight loss treatment, the men in the Cornell study who weighed themselves frequently weighed less than at the beginning. After two years, the average weight regained for men and women was close to zero.
The study has a number of limitations, the most concerning of which is that there's no way to account for the psychological motivation or pressure the participants felt knowing that the researchers were checking up on them so often.
"We tried to keep investigator involvement and participants’ desire to please the investigator at a minimum; no rewards were provided or congratulatory remarks were sent as a rule when stage changes were made," the researchers wrote in the paper. "Despite these efforts, for many participants, knowing that someone was watching them may have influenced study engagement and, therefore, weight loss over the course of the study."