Not hungry some days/ starving other days

I find that some days I am starving and other days I hardly have an appetite.

I eat very healthy. Mostly fruits, veggies, lean meats, nuts..etc. I eat no junk food. I also drink tons of water throughout the day. I also exercise 5-6 times a week.

Have any of oyu experienced this? How can regualte my appetite?

Me too for sure.

The best way I have found to regulate my appetite is to, ironically, eat at regular times regardless of my appetite.  I used to have this happen to me, that I would just get caught up in things and not feel hungry (because I wasn't listening in closely enough to my body).  Then I would start eating dinner, for example, and realize "man!  I didn't know I was this hungry!" 

Being disciplined about eating at regular intervals was the best way to even out my appetite.  You have to be conscious of times, however, and plan your meals to carry you for about 3/4 hours.  I did this by dividing up my calorie intake for the day into even "portions" - say 5 or 6 small meals.  Then, I just stuck to the schedule (with some flexibility, of course). 

After a while, I found out that my appetite had regulated to the point that I found myself feeling hungry at right around the time of my next small meal.  At first I did have to make myself eat according to the schedule regardless of my appetite, but this eventually crated a cycle where my body actually needed regular eating.  Since this kept my energy levels even throughout the day, I found I was able to get more done and was even more efficient in my workouts.  

For me, it was all a matter of creating an "artificial" schedule at first and making it repetitive enough that my body got used to it and and actually craved the routine - to the point where it became "natural" for my body to eat this way.   Now I just listen to my body for its own hunger cues... which tend to coincide with my original artificial schedule!

Hope that made sense :)

Good luck!