I've run a couple of hundred miles since March and cycled 678 (ish) since July but put on weight as Twiglets/Doritos are £1 a bag and I ate loads when in lockdown. I'm about 15 stone now which I can feel when running. I'm starting to look like Johan Hegg.
I'm going to try eating less. I don't think it's the smoking and drinking as I've been fine with that for years.