WooHoo! Welcome back. I know exactly what you mean. After herniating a lumbar disc in July I missed a couple months, gained 4+kg and lost fitness. But, I've been back on the bike for three weeks and things are turning around. The scale has haulted it's upward progress, I've even seen a small loss and the fitness is beginning to return.
Nothing like more bike rides to make you feel better.
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Birth Certificate, Passport, Marriage License Driver's License and Residency Permit all say I'm a Fred. I guess there's no denying it.