I do dump. I started at over 700, when I got down to 310 (my goal was 210), I started a program similar to Couch to 5K. I accomplished that and just kept going. Eventually I thought a marathon would be an interesting goal and I targeted the Valley of Fire marathon (outside Las Vegas).
I ran 5 marathons in a year starting about 3 years post-op, during which I was running 70 to 90+ miles a week.
I usually ran in the mornings before work, though there were periods where I did "2 a days". Right when I woke up I mixed up an ice-tea / Gatorade mix that wasn't terrible and drank it down. It woke me up and got me moving but I don't think it made much of a difference during my runs. During the runs I just did water. After runs I also did a regular yogurt for recovery.
I tried the little squeeze packs and found they were ok on normal days (10-13 miles), but they would cause me to dump on longer runs, so abandoned them and anything else. Again, I didn't perceive any difference with the squeeze thing.
My normal plan was 3 meals per day of 3oz protein, 1oz veggies. Because of the running I hit and shot way past a normal BMI. Eventually I was up to 5 meals per day plus a protein drink. The protein drink was instead of a 6th meal as I already felt I was eating all day. It slowed my weight loss. I hated (HATED!) eating so much, what a turn.
Good luck,
Tek