Your resting heart rate often goes up when fighting infection, so using more energy constantly to exist, in the same way that a 20st person uses more energy to exist than a 10st person.
But there's an offset that if you're ill, you'll cut superflouous energy use. If I have a cold, I'd have the energy for a walk rather than a run. Plus if you're isolating with Covid you're stuck in the house cutting a lot of incidental exercise.
So overall, most people would be more sedentary and lose less energy than usual.