It's sometimes hard not to be amused just seeing the title of things like this post "Pretending that evidence is difficult and complicated".
The first thing that occurs is the way the complex 'obesity' and weight loss is going around serving as an explanation for the results of repeated failure. That tells us nothing other than that approach is mainly futile. To boldly state from that what something may or may not be seems overly descive.
You can only assess the complexity of something if you've studied it rather than what you are convinced will/should/must be true. I never liked the 'complex' argument even when presented by fat activists, it seemed to me yet again to pay extreme regard to what has been a rather mindless approach of late. It behaved as if the study of obesity has been rational therefore we can draw rational conclusions from that.
How can we?
Anything is 'complex' if subject to endless blunder. They say simple when you know how, which can also mean simple when you are taking the right approach, when you are looking at it the right way up.
The idea that the repeated failure of a guess = complexity just gives yet another out clause to on the cynical farceurs who've run around like Keystone cops (place cursor on the +) in the face of facts they're studiously blanking. For their own ends.
Then there's the complaining about things like homeopathy. I was slow on the uptake when it comes to the medical ethics and placebos, due to the way 'advice' on calorie manipulation has flown in the face of that with a shocking disregard.
Apparently professionals are not supposed to engage in treating people on the basis of placebos because the investment of belief in them may require a false presentation of facts, or outright lying. And lying to patients is unethical even if it might benefit them.
It seems logical now, but I'd never have guessed, I thought I was just upset because of a petty sense of injustice.
Even if they have nothing else to offer and feel bad/ ashamed/ powerless about that.
They still shouldn't tell people something works to manipulate the patients behaviour, the authority we invest in them could make us very vulnerable to this form of persuasion.
They should acquaint their patients with the facts, so they are informed and can based their consent on meaningful. Doctors wouldn't want patients to consent to what they wouldn't if they had a more balanced view of the situation, would they?
Therefore telling people to do stuff that is ineffectual at best let alone harmful is unethical.