Put yourself in Ana's shoes.
She is desperate to find a new coach after several failed attempts.
She finally get someone who is willing o accept Ana's conditions.
This coach convinces her what she has to do to be successful, and Ana accepts.
I presume she does not know enough about fitness and nutrition to know the right question to ask about the process and possible side effects or body image issues.
As you said, she looks healthy so there is nothing to worry about.
As to people saying she has put on weight, I think there is a difference of opinion.
Some posters, including myself ( and ESPN commentators, not that they are authority in this sort things) thinks she has lost weight since Wimbledon.
I don't even want to address posters who stated that she was overweight she she won RG. That is ridiculous
I wouldn't completely agree with you on several grounds.
1. I don't think her current coach, Nigel Sears, convinced her to lose more weight. This trend of losing weight, regardless of whether we should classify it as a problem or not, started last year after Wimbledon 2010 when she tried to get fitter after a disastrous loss to Peer on grass. It is possible that Heinz Gunthardt, who coached her last year, recommended losing weight, but I don't think so, since it started several months after his tenure started.
2. I also don't think that Ana is completely oblivious about issues with regard to her fitness. I posted several pages ago the changes she had in her fitness situation in the past months, and she specifically fired Marija Lojanica, despite their friendly relationship, as they had a dispute over how much muscle she should have. This doesn't imply whether it was right or wrong decision, simply that she has an opinion regarding what level of fitness she should have. Last year, after her first round in Stanford, she also talked to the press about wanting more muscles ('like Serena, or Nadal', she said).
3. I don't think she has lost weight since Wimbledon. Granted I've only watched segments of her matches during the US Open Series, but from what I could see she isn't nearly as thin as she was around Indian Wells, and has a bit more muscle mass as well as a little more fat. Pictures and Youtube videos could be deceptive, of course.
The weirdest thing about Ana to me is that it's been so hard for her to get back to her former groove,
when she has been relatively blessed from injuries.
I just think that if I would be so extremely good at my sport like Ana is, and have all the possibilities of injury-free training,
I would refuse to play under my capacities for so long. I just can't imagine I'd allow it to go on like that.
But this is of course quite easy for me to say, sitting here on my matress with the laptop in my knee.
It's like she can't find the right level of intensity anymore. She's too excited.
Regarding her weight I don't have an opinion at this point...
She hasn't been completely injury-free. She hasn't had an injury as serious as that of, say, Safina, but she has had her fair share of minor injuries and illnesses - the ones I remember since Roland Garros '08 are abductor (missed Eastbourne 08), thumb (missed Olympics, could not hit forehands properly in Montreal), serious viral illness (withdrew midway from YEC 08), knee (missed Madrid 09), thigh (retired from Wimbledon 09), shoulder (changed service motion for Cincinnati and Toronto 09), ankle (retired from Cincinnati 10), abdominal (withdrew from Hopman Cup final, withdrew from Doha 11).
Injuries haven't necessarily crippled her ability to play completely. But Ana is a confidence player, and when she doesn't have full faith in the capability of her body to perform up to scratch, she can't take risks and she can't play her game. This leads to a slippery-slope: she can't get good results without playing and serving well, committing to her forehand and keeping her backhand solid; poor results leads to doubt and low self-confidence, which further undermines her faith in her game. Physical problems end up being psychological ones which are often the most difficult to undo.