My boyfriend and I have had a strange experience on this fast (day 41 now, going through day 42 - six weeks total). At the beginning of the year we were very strict with our diet, but still eating, for six weeks. He lost about 23 pounds and I lost 12.
For this fast, we started with similar amounts of weight to lose, but he was about 20 pounds heavier and 4 inches taller than me. As it stands now, I've lost 30.2 pounds and he's lost about 32 - can't remember exactly for him, somewhere in there. In fact, for the first 30 days, I was ahead of him in the weight loss by a pound or two. We're both pretty baffled that it came in so much closer, when he always loses much much faster than me.
Differences we've though of are that I probably drank more juice than him, especially compared to my caloric needs. This might have slowed down his metabolism more than mine? Also, I ride my bike for transportation, 3-10 miles per day, which might increase my release of weight.