You are on the right track, but on the non-fasting days, mind your calories and eat brown & green things, i.e. whole foods, vegetables, not refined stuff.
BTW there's a well reviewed short 5:2 book for 99 cents on Amazon.
https://www.amazon.com/Massive-Success-Intermittent-Fasting-Simple-ebook/dp/B01L12JMTU/ref=sr_1_8?ie=UTF8&qid=1473508945&sr=8-8&keywords=5+2