Weigh-in Once a Week or You'll Gain Weight

Stepping on the scale is common among dieters but how does the frequency of weigh-ins impact weight? A new study in PLOS ONE showed that the more frequently dieters weighed themselves the more weight they lost, and if participants went more than a week without weighing themselves, they gained weight.

The researchers analyzed 2,838 weight measurements (up to a years' worth of weigh-ins) from 40 overweight individuals (with a body mass index of 25 and over) who indicated that weight loss was a personal goal or concern. The researchers found that weight loss was related to how often individuals weighed themselves. "The more often you weigh yourself the more weight you lose," says to lead author Elina Helander from Tempere Univeristy of Technology in Finland. This observational study cannot prove causation - it may be that less serious dieters weight themselves less or that dieters who stop losing weight stop weighting themselves. The average time that participants could go between weighting without gaining weight was 5.8 days or about a weekly weigh-in.

Weigh yourself at least once a week if you wish to lose weight, and weighing yourself everyday may help you stay on track.

A previous study by the same research team found that your weight naturally fluctuates throughout the week and that most people weigh the least on Wednesday. To summarize both studies Brian Wansink, PhD, Director of the Cornell Food and Brand Lab and author of Slim by Design: Mind Eating Solutions for Everyday Life advises, “The bottom line is: If you want to lose weight, it’s best to weigh yourself every day. But if you weigh yourself only once a week, do it on Wednesday because that will give you the most accurate reading.”

Regular self-monitoring of body weight is an effective intervention in weight loss programmes and, especially, in weight maintenanc. Frequent self-monitoring is assumed to improve self-awareness, provide early detection of subtle weight increases and prevent weight regain after weight loss. Regular self-weighing is recommended as part of the behavioural therapy for weight management by the National Institute of Health and is deemed 'crucial' for long-term weight maintenance. Frequent self-monitoring may also promote weight management during the holiday season when the risk of weight gain is high.

Van Wormer et al. reviewed 12 studies that used self-weighing as an intervention for weight loss and weight maintenance. In 11 of the studies, more frequent self-weighing was associated with greater weight loss or weight gain prevention: weekly and daily self-weighers held a 1-3 BMI unit advantage compared with individuals who did not weigh themselves as frequently. For a 1.7 m-tall person this means a 3-9 kg lower weight. In the study by Linde et al., daily self-weighing was associated with the greatest weight loss outcomes compared with self-weighing on a weekly, monthly or semi-monthly basis, or never. Van Wormer et al. used self-weighing frequency to predict a weight change over two years; more frequent self-weighing was associated with slower weight (re)gain and, for obese individuals, also possibly weight loss. Fujimoto et al. found that subjects who were instructed to weigh themselves as frequently as four times a day and draw a graph of their weight lost twice as much weight as the group that only had behaviour therapy. In a 20-week study by Gokee-LaRose et al., one group was instructed to obtain daily weights with a digital memory scale whereas the other group was instructed not to weight themselves until week 11 and then to obtain weekly weights. Both groups received behavioural therapy. There was no significant difference in weight loss between the groups, but weighing frequency and weight loss were associated. Though it seems that frequent self-weighing is advantageous, the optimal self-weighing frequency is not known.