Paleo/primal success and failure

Since February 2006, I successfully lost 45 pounds or more three times. Except for the first time, I lost the weight using paleo/primal eating habits. The second time, I used intermittent fasting (IF) twice a week, for 18-36 hours, depending upon how long I could hold out. I exercised towards the end of the fast to maximize fat burning. My workouts were about 20 minutes of interval strength training. The third time, I lost the weight mostly by diet, without a serious exercise program.
The first time, I lost 50 pounds via diet and exercise (mostly walking). Between 1994 and 1999, I had done a lot of weight lifting and swimming. I was under 200 lbs. at the time, and added quite a bit of muscle, so weight loss was not much of a concern to me at the time. The whole diet yo-yo has frustrated me, but I keep trying to reset and try to achieve lasting success.
The reasons for failure: fast food, ice cream, and lack of exercise. The mindset that I'll eventually get around to losing my weight again, just not today, is a denial of reality which can only go on for so long. As Ayn Rand said, "You can avoid reality, but you cannot avoid the consequences of avoiding reality."
Now, the consequence is that I'm facing type 2 diabetes, so the stakes have been significantly raised. I've seen quite a number of success stories of people using a paleo/primal diet and exercise approach, who were able to reverse diabetes and return to normal levels. I prefer to do that than to depend on medication in the long term.

Updated the first couple of paragraphs to more clearly describe previous successes.