I invite all of you to take a look at this as well as the rest of Mark’s site. There are some very good articles there as well as an active user forum.
I personally lost about 30kg after deciding to take my diet and exercise seriously just over 2 years ago. My beliefs in diet and exercise have evolved over that time and I probably should create a more substantial post about my journey to the 70kg I am sitting at now. Since my list of pending items on my whiteboard is calling me, I will leave this short and let you go read the linked article.
Mark’s advice about primal living probably best match my views on this subject and is definitely a good place to start if you are looking to get started on a healthier lifestyle.