The folks at the Health At Every Size® Blog have posted some interesting answers to commonly asked questions about HAES.
One great response about whether fat is unhealthy:
It is true that extremes of weight in a large population of people are associated with more health problems – whether we are talking about the very thin or the very fat. However, the strength of those associations diminishes greatly when we correct for economic resources, physical activity, social support, weight cycling, access to good medical care, exposure to stigma, etc. What this tells us is that these other factors are more important if we care about health, rather than making everyone’s weight conform to some mythical “ideal.”
And in response to what’s wrong with wanting to be thinner?
For most people, wanting to be thinner than they are is like wanting to be taller or wanting to be a dolphin. You can wear high heels or learn how to swim really well, but at the end of the day you are still short and still human.
I tend to agree more with the first quote than the second. Weight is clearly not the same as height, but to be fair, long-term success can certainly be elusive.
Weight Maven is written by Beth Mazur. Beth believes that obesity is more symptom than cause and that the real problem is our Western diet -- especially sugar, refined grains, and industrial oils. Beth writes about nutrition, ancestral health & food policy. And cats! 
I can certainly relate, but the nagging thought is that this is as much a rationalization as a reasoned perspective. After losing 171 pounds over 6 or 7 years, I gained back 70 over another couple of years, but have held the line there without much difficulty for the last year. And I am now starting to lose again but in a less formal and structured way, just sticking to the principles of very low carb, moderate protein, high fat and small portions at dinner.
Breakfast and lunch are standard and no problem. Snacks before and after dinner, I concluded, were ‘habits’ and subject to behaviour change by a process I have called ‘metacognition and impulse control.’ Psychotherapists have another term for it, but I like my homespun variety. Anyway, it’s working for me at the moment as I try to lose another 50 pounds and then stay there. I will be far from skinny (still ‘fat’ even), but very happy. Getting back to my lowest is not the goal. Just to a healthy 225 pounds (5′-11″ male).
I tend to agree with them that weight is a poor proxy for health. I think what makes us fat also makes us sick, and that the changes in health markers seen from losing small amounts of weight are a result of the change towards healthier behaviors.
I think the jury is still out on the dangers (or not) of yo-yo dieting (Prof. Andro had a post on that just yesterday) but I tend to agree with them that weight cycling is problematic and that short-term diet efforts are a great way to weight cycle.
But while I agree that bodies come in a range of sizes, I think that the reality is that the curve is moving to the right and we’re seeing lots of people at weights higher than they would have been in the past. I don’t think you should be at war with your body, but I do think that for some of us at least, our weights are unnaturally high. And if that’s the case, weight loss is not unrealistic or impossible … as long as we find a way that works for a lifetime and doesn’t do more harm than good.
I have read a lot of comments on Fierce Fatties. They have all struggled with obesity and have finally come to the decision that they have to accept themselves as they are. Several have even mentioned that their vital factors are at a normal level. There are a few who write about their physical activity. Some have even stated that they aren’t eating unbelievable amounts of food or 10,000 calories a day. Some have talked about how they were brought up in the same household, eating the same food, as their thin siblings.
Personally, I think that it takes a lot of courage to say “no more.”
There are many people who don’t want to say “no more.” Your statement- weight loss is not unrealistic or impossible … as long as we find a way that works for a lifetime and doesn’t do more harm than good-is so very true but is still elusive for a lot of people.
I tend to agree that weight is not the same as height. If it were, I would not have gain 30 pounds as an adult, after I stopped growing. And try as I might, I cannot bring myself to be okay with being fat. I tried to take the HAES approach, and for a while I was convinced, but the truth is, I don’t like how I look and feel when I’m fat. I have problems with my joints, difficulty tying my shoes, trouble running for the bus, and I don’t like what I see in mirrors. I just don’t want to accept it. And I agree with you that what makes us fat also makes us sick. We need to change ourselves, but we also need to change the world in which addicting junk food is sold on every corner - because that is the biggest part of the problem.
I’m sympathetic with the HAES perspective that we don’t like what we see in the mirrors because we’re culturally conditioned. And that can change.
But … I sometimes think these folks who think fat is benign haven’t gotten past their 20s or 30s. I don’t think you need to be whip-thin, but I think folks are kidding themselves that our joints were meant to carry the kind of now almost normal excess weight for a lifetime. The big problem with obesity down the road may not be mortality, it may be disability.