I was 251lb last year (I'm using pounds so that most readers can relate, whether American twats or not haha).
I wore a 44" waist trouser size, xl or xxl tops and jackets, couldn't walk for 15 minutes brisk without sweating and frankly "big man", a common term of endearing reference by Glaswegians, could not be more accurate a word.
I researched and researched for at least 3-4 years and knew eventually all there is to know about the human metabolism, nutrition, exercise science etc.
Research is my way of procrastinating, and I overkilled it. I bought a treadmill, exercise bike, Olympic dumbells and barbells, state of the art running shoes and other gadgetry. Didn't use them once, they did however function as excellent tools for dust collection - if I ever gained an interest in that sort of thing.
One day after work, my boss was leaving at the same time as me. I walked with her towards my bus stop, as we were talking I just said I'll walk to the next one 5 minutes away. Then I skipped that one too. I said goodbye to my boss, and decided to go on the subway round the corner. Then for some reason I decided to just walk home - a 2 mile walk. I was so exhausted by it I needed to nap.
I did the same next day after waiting at the bus stop.
Then the next day, and did it everyday just because I felt like it. My contract ended 3 weeks later. I had spare time now. I still felt like walking however and I did. At first 2-3 miles, one day I went a random way, got lost, then found my way back home. Did 5 miles. Then a few weeks later, got lost again after a distraction of pleasant neoclassical housing on a street in the west end, then found my way home. I ended up doing 10 miles (I plot my route on google maps). Then I decided to do 10 mile walks. Then 12 miles, one day I did it twice just for fun, 24 miles.
I walked around 12 miles everyday, would normally have no appetite during and after them, having a huge breakfast next morning.
In 5-6 months I went from 251lb to my current weight of 181lb, 34" trousers and medium sized clothes.
I'm at a similar stage, last few pounds to go. The key is metabolism, I go for 16 hours with no food, but the walks mean an extended high metabolism for 6 hours (I take a few coffee/tea/hot chocolate breaks) and then lasts (after burn) throughout my sleep.
You MUST be accurate with calories, and you should take advantage of the afterburn, studies show around 35% of weight loss can occur whilst sleeping. On my break days I eat like a maniac, usually 4000 calories.
The irony is, after all my research and elaborate planning - I ended up starting unintentionally, doing a simple exercise when I felt like it and eating anything on some days. But my research allowed me to accurately estimate my energy cycle, and allowed me to predict my progress to the pound. My scales record weight at the 0.1 of a pound, I could measure progress daily.
Oh a tip - cinammon. Used it for months a lot, later discovered it has a powerful metabolic boost.