I think it's more complicated.

It could be psychological in that upping a 100 calories or so could make you feel prepared to work out harder.

Or it could be physical. I know eating properly helped me exercise harder after I started to burn out running too far, too often and not eating enough.

Or it could be something else, like a calorie is not a calorie. So eating 200 calories more of fish might speed your weightloss if it replaced 100 calories of candy. I'm pretty sure that would work with me.

It's never candy. My calories have mostly been very good quality veggies, proteins like baked chicken etc. In any case it's resolved so I'll keep trucking along at what it was at.