We all know how to lose weight — eat less and move more. But for many of us, that prescription just doesn't seem to be attainable, or if weight loss is achieved it is difficult for many to maintain. However, multiple studies have shown that keeping track of food intake — a food diary — does seem to help. So would keeping track of activity also be useful? Would it improve upon results using just food diaries? A group of researchers led by Dr. John M. Jakicic from the Physical Activity and Weight Management Research Center, Pittsburgh, PA set out to test that idea. The report of their investigation was published in JAMA.
To determine whether the addition of an activity tracker would improve on weight loss and maintenance of that loss, the investigators recruited 470 individuals who took part in their 24 month study (the Innovative Approaches to Diet, Exercise and Activity or IDEA study). For 6 months, all received standard interventions which included a weekly group meeting, and keeping food diaries; they were also prescribed calorie intakes based on their beginning weights. After that point, they also received telephone contact monthly, and weekly text messages. For months 7-24, half the participants were randomly assigned to wear a web-based interface worn on the upper arm that monitored and reported their energy expenditure and activity levels (the enhanced weight loss intervention group, or EWLI. The rest , the standard behavioral weight loss intervention group (SBWI) continued to received phone and web-based interactions. All the participants were between 18 and 35 years old, and their BMIs ranged from 25 to under 40 at baseline (those would include overweight and obese individuals).
At 6 months, all the participants had decreased their BMIs, but the standard and enhanced treatment groups didn't differ in the amount lost. By 12 months, the standard group had lost significantly more than the enhanced group, and this difference was maintained at 18 and 24 months. Both groups lost similar amounts of body fat over the 2 year period.
For both groups, the amount of weight loss maintained tended to decrease over the course of the study. The authors conclusion was obvious: "Devices that monitor and provide feedback on physical activity may not offer an advantage over standard behavioral weight loss approaches."
We shall have to continue to search for other means of reliably motivating individuals to lose weight — or better yet to prevent their gaining it in the first place.
