I've been doing simplefit for about 5 months now, and track some statistics. According to these statistics, on average I increase my strength by 10% each week.This is true even after 5 months - although I have recently switched to doing the exercises with a 10kg weight west. So you will not see dramatic results, it is more a continous improvement.
Food is very important: you can either lose weight, or gain muscles. I think it is best to lose weight first (if you want), best with a ketogenic diet (low carb, high fat). If you want to gain muscles you have to eat some carbs, preferably after the exercise and only if you were really training hard.
Some very good sites to get information about nutrition / losing weight:http://www.reddit.com/r/ketohttp://www.reddit.com/r/paleohttp://www.reddit.com/r/leangains
Also, I have a collection of videos about Low Carb High Fat: http://j.mp/lchf