The problem is, I have yet to see a piece of science that suggests diets work. I'm not even slightly interested in loosing ten pounds for a year, and I think most fat people aren't; the fantasy is thin, or at least average weight, and it must last forever. . . to satisfy the fantasy, anyway.
Not that ten pounds lighter wouldn't be welcome, but I'm not willing to make dieting an obsession for the rest of my life for ten pounds. Honestly, I'm not sure I'd be willing even to be seventy-five pounds lighter, though it's definitely a more attractive possibility.
But the chances of that, not to pun, are incredibly slim. Take this analysis of success rates at weight watchers:
"38,000 people who reached goal weight per year sounds like a lot. But actually it turns out to be a really small number. I found a business article from back then that stated that Weight Watchers had 600,000 attendees in the U.S. in 1993. Divide 38,000 lifetime members per year into 600,000 and my calculator says that each year only about 6% of Weight Watchers members (give or take) reached their goal weight (presumably 94% failed).
Now before you get all impressed with Weight Watcher’s 6% success rate, let’s step back. For one thing, the successful 6% weren’t so fat in the first place. The 2001 study says that most were between a BMI of 25-30 (i.e. “overweight” but not “obese” – to use definitions I find silly). The 2007 abstract says the average starting BMI for that study was 27 – which is well below the average Weight Watchers participant. So in order to achieve goal weight the average lifetime member probably had to lose less than 10 lbs and would have to include a lot of people who had even less to lose. [...]
And what about the number we’re really looking for – how many people actually become “normal” weight long-term using Weight Watchers? It turns out only 3.9% of the golden 6% were still at or below goal weight after 5 years. By my calculations that means 3.9%*6.3% = 0.24% or about two out of a thousand Weight Watchers participants who reached goal weight stayed there for more than five years."
Frustrating, because there's no indication what percentage of weight watchers attendees are there to maintain, or have an initial goal that would reasonably take them more than a year to reach. Still, all the evidence I've ever seen suggests that most dieters move from one diet to the next, and if most fall within that pattern, she should at least be in the right order of magnitude.
Then there are these excerpts from the same blog:
"Even in the studies with the longest follow-up times (of four or five years postdiet), the weight regain trajectories did not typically appear to level off (e.g., Hensrud, Weinsier, Darnell, & Hunter, 1994; Kramer, Jeffery, Forster, & Snell, 1989), suggesting that if participants were followed for even longer, their weight would continue to increase. It is important for policymakers to remember that weight regain does not necessarily end when researchers stop following study participants."
"Here’s something doctors don’t tell their patients: 41% of people who go on diets weigh more a few years after the diet, then they did before they began dieting.1 Since I’m a blogger, not a scientist, I’ll go ahead and make the irresponsible comparison: Dieting is significantly more likely to cause long-term weight gain than weight loss. That’s a Surgeon General’s warning that should appear on every diet program and product on the market."
Again with the frustrating; most people naturally gain some weight as they age, and arguably, Americans just gain weight over time in general, so the follow-up weight gain of dieters is meaningless unless one is comparing it to a control group.
There's so much bad science, and so much financially motivated science, in this field--it can be hard to wade through. Pro-diet sources define "success" at dieting in a way no human being does (like ten pounds for a year), and fat acceptance writers publish things like. . . well, like what I just quoted. It's not at all solid, but it is enough to give me pause about dieting. Supposing that dieting gives me only a 10% chance of reaching my goal weight, and a 20% chance of regaining more (above the curve or normal weight gain) than I've lost within five years, it would still a stupid move on my part.