Thanks for the question. I showed only 7 yo-yo cycles in that chart because that was all the hard data I had. I've actually been doing it since 1991, beginning with a drop from 180 to 140 when I decided to run the 1991 USMC marathon -- which I completed in 3 hours 45 minutes, missing the Boston Marathon qualifying time by only 20 minutes. Most of the subsequent yo-yo attempts were driven by a desire to repeat that marathon, losing weight while training -- but never making it to the starting line again due to consecutive training injuries -- and then regaining the weight for the next 6-18 months.
My other motivation in losing weight -- even more important than weight, waist, and BMI -- is my type II diabetes. When off my diet, I take morning readings that slowly rise until they reach 200 or more, which is when my "Danger Will Robinson" alarm wakes me up to get my diet back in gear. As soon as I start restricting my calories and closely monitoring glucose before and after every meal, the numbers drop rapidly to the 80-100 range. So my A1c fluctuates between diabetic 10.5 and non-diabetic 5.5, depending on whether I am dieting.
So perhaps the best answer to why I have kept failing is the old saying, those who fail to remember the past are doomed to repeat it, with the two biggest mistakes being unrealistic training goals and treating myself to fancy dinners and relaxing the constraints when reaching intermediate goals. Duh...
But what is also different this time is that I have changed my focus. When I first learned about BMI I created a "Reverse BMI" scale from 18 to 32, showing side-by-side what my weight would be at each BMI point (e.g., Lowest-Normal 18.5 = 118.1, Average-Normal 21.0 = 134.1, Overweight 25.0 = 159.6, Obese 30.0 = 191.5, etc.). So my short-term goal would be to get below 159.6, and long-term goal would be to get to 134.1. Over the years, my spreadsheet dashboard evolved until it became quite elaborate, now even acknowledging %muscle and the lost muscle mass referenced in my initial post.:
The problem, of course, is that these measures are insensitive to the health risks of the visceral fat that I never tackled directly, thinking that it would be solved if I ever got below "Overweight" on that scale. As it turned out, the linear projection estimate of future waist vs. weight in the green box never fit the reality, since I'd incorrectly assumed I'd be at 9.5% fat with a 32" waist at BMI 21. With better information I've now reset the intercept downwards to BMI 18.5. See the green "goals" box.
The bottom line answer to your question, therefore, is that I've learned from my mistakes. After 15 weeks I'm still (1) walking instead of running, (2) counting grams carb / fat / protein and calories for everything I will eat and drink at the beginning of the day instead of the end of the day, (3) checking my glucose before and after every meal, and (4) tracking weight / waist and fat / muscle percents on a daily basis.
Most of all, I've stopped rewarding any intermediate progress with off-diet food. Even when planning special event dinners, whether a whole lobster dipped in drawn butter, or a porterhouse steak and baked potato, it gets counted gram-for-gram, calorie-for-calorie before I make that reservation, and it is budgeted within the context of my nutrition allowance for that week. On those occasions, I routinely ask for a carry-out container as soon as I am served, and put half the meal aside before taking my first bite.
Thanks again for listening.