The New York Times Magazine had a nice, short article about fat acceptance and Health at Every Size, called Losing the Weight Stigma.
Says writer Robin Marantz Henig:
Several studies suggest that if the aim is getting healthier rather than slimmer, then in the long run the “Health at Every Size” approach works better than dieting. In 2005, Bacon led the only randomized control trial to date that tested this hypothesis physiologically. She randomly assigned half of the 78 subjects, all women, to a “Health at Every Size” group; while they lost no weight, their healthier behavior led to lower blood-pressure and cholesterol levels, which stayed low even two years later. In the weight-loss group, more than 40 percent dropped out before the six-month low-calorie diet ended, and at the two-year follow-up, the average dieter had regained all her lost weight, and the only measurement that dropped was one for self-esteem.
And that first sentence really hits home the difference between HAES and dieting: health vs. weight. True, people diet to improve their health, but the ultimate goal is weight loss. You don't lose weight until your cholesterol levels improve, or your blood pressure goes down. Those are just side effects. You lose weight until you hit "goal."
Health can't be measured in numbers. Health is measured in quality (friends, joy, family, movement, love), not on little charts and certainly not on a scale.
(Note: image from the NYT article)