Hi there!
First of all, one of the things about BSD is that it helps your body change its hormonal response to burn fat cells for energy rather than refined carbs. This will mean that even without refined carbs (and you will get plenty of other carbs from all the allowed vegetables) you will find you have lots of energy.
I understand about the bread – mmmmm – but I really recommend giving it up for the 8 weeks as even small amounts of refined carbs make it more difficult to give up the rest.
Why don’t you give it a go and find other things to put your breakfast eggs on – portobello mushrooms? Baby spinach? – and see how your energy levels are still fine, if not better.
Then you can go back to your bread at the end of the time.
I know other experienced BSDers will agree that little compromises can lead to more damaging ones if you’re not careful.
I also exercise and found no issues with energy levels after giving up refined carbs – indeed did my BSD on 20-30g of carbs (the good ones) per day.
Hope that helps! 🙂