No reason to be nervous. Remember, it IS going to be tough, but it will be worth it. The first week helps you really break any food addictions. So getting through that first week is crucial. You won’t be truly hungry because you’re plenty nourished: protein, good fat, fiber, and just enough carbs to make your workouts effective. But you may experience cravings, which is false hunger. This is natural, normal and it needs to happen to really rewire your taste buds and nip the food addictions. So keep that in mind: you will always be nourished and full.
But think of it as rehab: it will be tough for a while, but it will be life-changing. In fact, the most common question I get with people on their 4th week is, “can I do another week?” They didn’t think this way during week #1 however! It just gets easier as you go.
Take the measurements and pics for sure, and stay off the scale except for a once per week weigh-in following the weighing instructions.
If you have any questions for me, be sure to post them in the Ask Chris forum, where I’ll be sure to see them: http://tnation.t-nation.com/free_online_forum/diet_performance_nutrition_bodybuilding_velocity?pageNo=1