I don't know if the diet itself will do it but if you are consuming less calories than your body needs then it can do some damage.

I was doing a 1200 calorie diet (300 less than what is recommended... don't do that...) and I was prepared to go with it for 3 months on top of regular workouts. I finished the first month easily. I felt better than I'd ever felt in a long time. However during the second month I started eating a lot less than that 1200 calories and that's when things went bad.

My body became weaker and I was unable to complete the workouts. Motivation went straight out the window approximately 2 days after I stopped eating the 1200 calories. Soon after I was simply unable to do much of anything. I basically shut down. It DOES NOT feel good to shut down after a month of intense work. Days became weeks and weeks became months. I haven't recovered from that since. This started in November...

So first I would suggest that you make sure that you are getting the correct calorie intake for your body. I have no idea how I survived that long on 1200 calories but it was a bad idea anyway. Secondly make sure that you can commit to your diet. If at anytime you find yourself unable to do this then the only option is to just eat whatever you have. I felt guilty and just didn't eat. Don't do that. Lastly make sure you're getting as much sleep as night as you can.

If you are unable to do all the nerdy calculations then you can join http://www.bodybuilding.com/. They have all the stuff you need to keep track of EVERYTHING you will ever need to keep track of. The only things you should keep track of are weight, body fat percentage and waistline but you can do more if you want. You can get your body fat percentage here:http://www.bmi-calculator.net/body-fat-calculator/ If you don't have measuring tape then you can grab a belt and a ruler and do it that way.