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Weight Watchers: The proven Weight Watchers approach makes losing weight simpler than ever.

Some dietary interventions for weight loss result in the person losing weight for a short term period, only to regain the weight afterwards. Does Weight Watchers succeed in helping people to lose weight permanently? Is it proven to work?

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    Note: Weight Watchers is basically a calorie restriction diet plus personal support. – Sklivvz Jul 7 '12 at 13:35
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    How do you define if it is PROVEN to work? The problem is, if it has worked for ONE person, then it clearly CAN work. But if it has not worked for every person who has tried it, then does it work? What if the person is not committed to it? Does that count? How do you verify that it worked for everyone who was committed to its use? So clearly a valid metric for such proof is needed. Without such a metric, the answer is anything you want to see: it does work, and it does not work. – user3344 Jul 7 '12 at 14:07
  • @woodchips: I share your concern that the question is a bit loose, and the answer is not "It works for everyone" nor is it "No better than placebo." However, there are some pretty obvious metrics to use, so I don't know why this treatment would be any different to others when determining its efficacy. – Oddthinking Jul 7 '12 at 14:33
  • My younger sister (only 11) has been doing the program and has lost some weight because of it. It's a point system whereby finding the amount of "points" everything you eat is, you can ensure that you don't eat too much. Unfortunately, it doesn't do anything to teach you what's good or bad to eat, just what is more "points". Because of this, she sometimes skips a meal to have a fatty snack (chocolate or ice cream) and doesn't understand that just because she has "points" left to use, that it's OK. TL;DR: It's better to just exercise and read some nutrition books that do weight watchers. – mowwwalker Jul 7 '12 at 19:59
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    No way it's better to exercise! You need to run 30-60m every day to compensate the calorie reduction of a programme like Weight Watcher. Good luck with that! – Sklivvz Jul 7 '12 at 20:27
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TL;DR: It works well for some people, but not everyone.

The question is tricky because:

  • Weight-Watchers is not a single, homogenised regime, but has changed over time.
  • There are likely to be subclasses of patients with different initial conditions. (Is "patients" the right word? Possibly not, but I am going to stick with it, as I am treating it as a medical intervention, even if I am not intending to imply an illness.)
  • Different patients are going to stick with the program for different lengths, and for different reasons. How do you judge the long-term effects? By the few that stick to the program or all the people who started, including the attrition?
  • "Permanently" is difficult to confirm with a finitely-resourced study. "Short-term" isn't a clear range either (Is 6 months short-term? 1 year? 5 years?)

Let's look at some research anyway:

Four Weeks, Effectiveness

985 patients were randomly assigned to either Weight Watchers or self-help.

After 4 weeks:

Weight Watchers participants showed greater improvements than Self-Help participants on all measures; weight losses averaged 1.87 and 0.77 kg, respectively. The superior outcomes shown by Weight Watchers participants on measures of vitality and eating behavior were still evident when extent of weight loss was controlled. Weight losses across different sites, incomes, and levels of obesity were similar.

Twelve Weeks, Attrition

These studies show a majority of patients drop out, but those who do are more likely to have started out thinking they couldn't control their weight.

Fred R. Volkmar, MD; Albert J. Stunkard, MD; Joseph Woolston, MD; Robert A. Bailey, High Attrition Rates in Commercial Weight Reduction Programs Arch Intern Med. 1981;141(4):426-428. doi:10.1001/archinte.1981.00340040022010

In a study of 108 women enrolled in a commercial weight reduction program, we found very high attrition rates; 50% of the members dropped out in six weeks and 70% in 12 weeks. Similar attrition rates have been reported in five other programs in three different countries. Very high attrition rates diminish the effectiveness of commercial weight reduction programs, and they suggest caution in the interpretation of data based on weight losses of persons who remain in these programs.

They had a much smaller drop-out rate: after 12 weeks, 101 of 414 patients.

dropouts were significantly more likely than stayers to report low self-efficacy at the beginning of their memberships. Dropouts were also significantly less likely to feel successful in weight control and behavior change, even though their rates of weight loss did not differ significantly from those of the stayers

Six Months, Effectiveness

They had 423 patients, who were either given 2x20 minute sessions with a nutritionist and some printed materials, or Weight Watchers membership.

After 26 weeks, subjects in the commercial program, as compared with those in the self-help program, had greater decreases in body weight [mean (± SD) −4.8 ± 5.6 vs −1.4 ± 4.7 kg] and body mass index (−1.7 ± 1.9 vs −0.5 ± 1.6 kg/m2, both P <0.001) in intention-to-treat analyses.

A structured commercial weight-loss program is more likely to be effective for managing moderately overweight patients than brief counseling and self-help.

One Year, Effectiveness and Attrition

This study assigned 40 people randomly to Weight Watchers (and 120 to other programs), and at the end of one year found the average loss was 3.0 kg (standard deviation: 4.9 kg), with 65% of the participants completing the program. (They made a "reasonable but imprecise" assumption that people who discontinued the study remained at the same weight.)

Fifteen Months After Hitting Goal Weight, Keeping the Weight Off

Stuart RB, Guire K. Some correlates of the maintenance of weight lost through behavior modification. Int J Obes. 1978;2(2):225-35.

This study was done on patients who lost their weight in the mid 1970s. Techniques have probably changed since then.

They followed up with 721 members of Weight Watchers classes, after they had reached their goal weight (at which point some stuck to the program and some didn't.)

They had all lost of a lot of weight before hitting their target weight:

The group averaged 73.2 kg (162.1 lb) before losing 19.0 percent of their body weight to reach goal weights averaging 59.6 kg (131.2 lb) in an average of 31 weeks.

Note: This is only looking at the people who achieved their dieting goal. Those who dropped out early are not included.

Most were within 5% of their initial goal weight:

Fifteen months after reaching goal, 24.6 percent were below goal, 28.9 were within 5 percent of their goal, 17.5 percent were from 6--10 percent above their goal and 28.9 percent were 11 percent or more above goal. Those who maintained their goal weight, as opposed to those who regained, tended to have several things in common: they attended classes after reaching goal weight in the same locations and with the same lecturers that assissted their weight loss; they had lower initial weights: they conceived of themselves as 'overweight' when they were approximately three pounds above goal; they had improved self-concepts; they made more lifestyle changes supporting weight maintenance; and they continued, after goal, use of many of the techniques used to reach goal weight.

So, longer-term, Weight Watchers remained effective for most of them, especially those who stuck to the program.

Five Years After Hitting Goal Weight, Keeping the Weight Off

Like the previous study, this one only looked at people who had achieved their target weight, ignoring any who had dropped out early. There were 699 in the sample, and an additional 217 used to oversample to calibrate.

The percentage of Weight Watchers lifetime members who maintained at least 5% of their weight loss 1, 2 and 5 years after successful completion of the programme was 79.8, 71.0, and 50.0, respectively. The percentage of participants who remained below their goal weight 1, 2 and 5 years after completion of the programme was 26.5, 20.5, and 16.2, respectively.

So, the bottom line, is 16% of people maintained their weight after 5 years, and 50% managed to keep at least a bit of the weight off. This suggests that 50% were NOT able to keep their weight off for 5 years.

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    "subject" might be a better term than "patient"... but it's not really worth editing to change that. :) – Flimzy Jul 7 '12 at 17:42
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Let me add some anecdotal evidence (of myself) plus some thoughts on why it works.

Over the course of the last 6 months, I have lost 12kg (down to 81 from 93) using only the points program (no support meetings), and it hasn't been all that hard, so I expect that I'll be able to keep the weight.

As for the reasons:

  • It provides very simple rules - this reduces the potential for getting sloppy about following them.
  • It's convenient, especially if you use the mobile app - no need to plan out every meal in advance
  • It is flexible - you can eat whatever you want as long as you stick to the budget (so you won't drop out because you can't live without chocolate cake), and there is a system of weekly "extra points" that allows for the occasional huge dinner without making you feel that you failed and "now it doesn't matter" (a common problem with other diets).
  • It subtly encourages exercise (by letting you earn points) and eating lots of fruit and vegetables (by making most of those have no points - which makes eating them convenient, since you don't have to factor them into your budget).
  • It encourages slow, consistent weight loss rather than quick, impressive results (which typically require diet changes that are not sustainable). Of course this also means that you'll pay them money for longer, since it's based on a monthly fee.

All in all, I think the key to success in losing weight is to acknowledge that it's not just about calorie input and output or even in general about what you eat. People are not machines, and to be successful in changing habits and defeating unhealthy impulses you have to take psychology into account. Anything that reduces the amount of willpower it takes to stick to a diet will improve the chances of long term success. And Weight Watches seems to do that pretty well.

Some of the information contained in this post requires additional references. Please edit to add citations to reliable sources that support the assertions made here. Unsourced material may be disputed or deleted.

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