I've seen the argument being made that some people's bodies are highly resistant to attempts at weight loss.
Something along the lines of that if they try to go on a diet the body will fight the attempt to use stored fat so hard that they'll end up with low blood sugar and faint.
I don't recall the exact argument being made but I think that's the overall gist -- not that it's possible to somehow violate thermodynamics, but that for some people it may be near impossible in practice while remaining healthy/functional for weird internal biochemistry reasons.
Something along the lines of that if they try to go on a diet the body will fight the attempt to use stored fat so hard that they'll end up with low blood sugar and faint.
I don't recall the exact argument being made but I think that's the overall gist -- not that it's possible to somehow violate thermodynamics, but that for some people it may be near impossible in practice while remaining healthy/functional for weird internal biochemistry reasons.