Well those particulates and gases are still produced in the production and transport of food. If you eat more food then more will have to be grown and transported.
The extra movement that increases the resting metabolic rate would cost about 500 kcal combined with the load. Estimating for an hour of cycling daily.
This means about one extra meal to match which would actually cut into waste if it is done smart. Or perhaps you do not even have to adjust anything. (obesity is a thing)
Some of that food could be a carbon sink, depending on how it's grown, how it's transported and where it ends up. With the later it might even get a second life generating electricity.
It's not much, and it's comfortably within what most people are eating already.