My apologies if I've offended with my choice of words, which I confess were typed 'off the cuff'.
On reflection, I should not dismiss ADHD in some simplistic language.
However, after some research I know that there is no simple clinical test for ADHD and therefore I think it's not completely unfair to suggest that in some cases there may be a tendency to attach the convenient label of ADHD to a collection of symptoms that may in fact be indicating a different root cause.
As to ritalin, I cite this information on methylphenidate side effects which includes appetite suppression.
I think there are undoubtedly other contributory factors to the problem apart from food so please don't imagine that I'm saying that diet is it, full stop.
Pace and pressure of 21st century life, constant stimulation from multiple sources engineered to heighten sensation (TV, computer games are obvious new factors in the landscape for the current generation) as well as genetic disposition seem to me likely to be involved.
There's also an interesting argument to be made that what are being regarded as diseases to be cured are actually an evolutionary reaction to the levels of stimulation in the environment that haven't been present until the last 20 or 30 years - and that this evolutionary reaction (if that's what it is) may turn out to be an advantage in the longer term.
Certainly I've read discussions online involving people who have been diagnosed with ADHD and regard what we might call 'normal' levels of stimulation as tediously boring, going on to say that they can't concentrate unless there are dozens of things all happening at once.
I can't find the exact conversation I've referred to above, but here's one along the same lines - however this is more anecdotal "I know someone..." rather than "I am...", which is far less satisfactory as evidence.
Thanks for replying, and pulling me up on my poor choice of words. I hope my reply gives useful clarification.