Health isn't defined by a 6 pack or low body fat. I agree that it should be about long term habits and being healthy. Weight loss is generally correlated to being healthy.
OT uses people who are obese and as soon as they start eating a diet which tracks calories they are obviously going to lose weight. If you actually watch the show the weight loss is now just a factor with them looking at medical factors such as blood pressure, fitness tests and measurements.
I don't believe they are putting them on highly restrictive plans. Actually even this week they talked about changing somebody's calories because her 'normal' activity is much more active than others.
They are teaching long term habits, how to cook, what to eat and addressing some of the mental issues contestants have.
It goes far deeper than many of the '8 week transformations' sold on line.
I don't mind Siobhan advertising that it's amount losing weight slow, eating right and being in a slight calorie deficit. That's fine, but she doesn't practice that, and she doesn't come across as being fit or healthy.
I imagine because she doesn't cook makes it hard to accurately track, a lot of hidden calories in that food (oils, sauces), and then there's the booze. I imagine if she completely abstained for 6 weeks with her level of training she would drop a few kg.
However, if she's happy with her body now, so be it but she needs to be more honest on how many calories she's eating and the fact she's working out a lot of keep the weight off.