I did the math myself a couple years ago using numbers for my life (measured e-bike range on throttle only, full charge Wh consumption measured while charging, my local power grid CO2 production per kWh, etc) and manufacturer estimates of production carbon emissions. Personally I have to work hard to maintain weight and consciously eat more when I lose it, so for me calorie consumption is actually zero sum.

That math showed my ebike on my grid was an order of magnitude more emissions-efficient per mile than an acoustic bike powered by an avg omnivore diet, and still something like 3x more than the avg vegan diet.

Once the increased manufacturing emissions for an ebike were taken into account it just changed the break even point: mine was something like 1k miles for omnivore (after which ebike is better than acoustic), 3k miles for vegan.

But really all of that math only compares ebike directly with acoustic, not miles traveled across all modes. I put far more miles on my ebike than I did on my acoustic, and many of those miles would have been in a car. As soon as you consider that factor, there’s no question of the emissions benefits of e-bikes.