Am I considered underweight for the NLP?

[SethP]

I'm a 29 year old male, 5ft 10in, and I weigh 170 give or take a pound or two. I thought this might go in the Nutrition section, but I wasn't sure.

I started the NLP in earnest (strictly barbell training and none of the extra stuff) about a month ago and gained roughly 3 pounds since then. I figure that I'm going to gain more mass as I progress. I'm still making gains in the weight I can move on a daily basis, however I think I'm still underweight when taking the NLP into consideration. I'm 29, not 18, and I know that as you age your body process protein less efficiently and you tend to need more of it. I imagine that goes for carbs too. However, I'm still trying to judge how much I should be eating. Should I be shooting for the 3500 calories in the 6-9 months of the NLP (currently taking in 2600 daily)? Am I considered underweight for the NLP? I think I am, but wanted someone more experience to weigh in. I'm fairly certain I'm underweight for this and 2600 calories isn't enough, but I don't want to screw this up anymore than I may have already.

My days vary in terms of activity: I lift 3 days a week (M, W, F) at about 5:00 in the morning before work on 6-7 hours of sleep, not counting the nights where my 2 year old wakes us in the middle of the night. I have a desk job working in IT, 8-5, 5 days a week. I'm mostly sedentary at this job, but as I maintain the infrastructure around a manufacturing shop, there are days where I have to walk a lot, climb a ladder, and sometimes pick up loads of almost 50 lbs. I also practice TaeKwonDo and have been doing this for nearly 21 years. It's not a grappling sport and there's lots of jumping and kicking. I do this 2-4 times a week for roughly an hour. If I'm not working out, I'm instructing and I'm on my feet the entire time. I also have a 2 year old that I'm constantly chasing around at home after work. I also use the weekends to do things like wash the car, mow the lawn, general upkeep and repair around the house.

[Mark Rippetoe]

A Clarification | Mark Rippetoe