I guess it depends on what you are wanting to accomplish with both OMAD, and exercise. If you just want to get exercise, then it probably doesn’t matter when you do it as long as it works best for you.
On the other hand, if you are looking for weight loss and autophagy, then exercising before your meal is definitely the best option. After you have fasted all night, your body is burning fat for fuel, and you are in autophagy; so when you exercise, you burn more fat and do it faster, as well as getting rid of the old and worn out cells in your body.
Even if this was not part of the equation, I feel much better when I exercise before eating. I have tried exercising after having breakfast, and even before I started OMAD, I didn’t do well at exercising on a full stomach.
When I exercise, the hunger seems to go away, and when I get back home from the fitness center, then i am totally ready to refuel my body with healthy food.