I think it is important to note though that you should do what works best for you at the start. It’s more important that you start working out, than that you set that extra barrier of effort you need to surpass simply because 'it is considered more effective’. It's all about building habits at first. In my particular case, after failing 5 weeks to get up early to do my trainer-advised-before-breakfast run, I simply switched to evening runs, and have since been burning fat every evening for the past two months.
Do whatever gets you moving, may that be before or after breakfast 🙂