I am 60, have been on ZC for a few years (2006-2008), then did 7 months of "healthy" hi carb eating -m don't ask, very BAD judgement on my part - and have been back on ZC since April last year. Have eaten mainly low carb since the mid seventies, with a few periods of "normal" food in between. Never again.
I am not on my optimum weight yet but getting there, but am fit and healthy - and happy <g>