I've heard losing more than 3lbs can be unhealthy. I think I'm doing well and I feel great, but the last thing I want to do is yo-yo back up to my original weight eventually.

Because of my job, I rarely have time to count calories, but I'm definitely eating healthier than before. I try to never go hungry, and I've been exercising 3-4 times per week (HIIT and strength.) I've stopped eating any HFCS, switched to wheat instead of white bread, and virtually eliminated soda. I've been slowly adapting my diet for the past 4 or 5 months, but just recently have I started exercising again.

I used to be 355lbs, dropped down to 270 in college, and had slowly made my way back up to 320 over the course of a couple years. I've gained a significant amount of muscle in the past month, but I've also lost almost 20lbs, which means I've probably lost almost 30lbs of fat.

This would mean I've lost over 6lbs of fat per week. Is this too much with all things considered? Typically for breakfast I'll drink a protein shake with a few egg whites on toast, or a bowl of oatmeal. For lunch, a sandwich, or maybe rice and beans or a light pasta if I'm craving some carbs. For dinner, I just eat something sensible and balanced. I get meals in between in the forum of granola and/or protein bars and shakes.

I'm not looking to live a hardcore bodybuilder lifestyle. Being healthy is my only goal. I could care less whether I have 6 pack or not, I just want to not have a heart attack by age 50 like my father and his father did.

So my question is, for someone of my size, 6'6" with a football player type of frame, is 5-7lbs healthy for my first month or so, or do I need to be doing something different?

I don't think your body can metabolize 5 or 6 pounds of actual fat per week. Some of that might be muscle.

Well I did think about that, but that's why I mentioned I've gained a significant amount of muscle as well (or at least it appears so). It may just be definition from fat loss, but I don't think I've lost really lost any. I've definitely noticed myself adding more weight to all the machines to wear me out.

I'm not saying it's impossible that I've lost muscle, but it surely doesn't feel that way. Maybe I'm just increasing my muscle endurance though?

It's more likely water loss than muscle.

Plus the more you weigh, the more you lose when you go on a weight loss plan. You've seen the biggest loser show right?

So long as you are eating enough, I don't think it's a big deal.

I once read the 70% of the weight loss in the first 3 weeks of a new diet program is usually water. Wish I had a link to show, but I don't. Surely if you google, you will find some answers.

I'm no expert on the matter, but I have lost 97 lbs since July 9 2008.. so a little over 6 months. The majority of that came off in the first 4 months and now I guess my body has adjusted to my new normal of being active and eating healthy it has slowed to a more "normal" 1-2 lb loss a week. I know for me even if it was unhealthy to lose more than 2-3 lbs a week I was unable to stop it. All I did really was start going to the gym & quit living off soda & junk food. I think that has a lot to do w/ it why people who are really obese lose more when they start a diet/exercise program. I went from living off of fast food & soda & no exercise at all. to exercising at least 3 days a week and watching what I eat and drinking water only.so it is definetly possible & even if it is "unhealthy" it's better than carrying around extra weight unless you are doing something drastic like starving yourself to lose the weight which it doesn't sound like you are doing... Good Luck!!!

I haven't read this entire thread, but one statement from the OP led me to feel a need to remind you that it's very possible to get stronger (as in lift more weight on your machines) while adding no muscle. Or even losing it.