>Any suggestions from former fat people on what they did that made a difference?

I have lost 70 lbs - and I am still fat, but continue to work on it.
320 lbs down to 250lbs at 6'3"
Have kept it off for about 3 years now.

The thing that made the difference for me was Diabetes - you really don't want to go there.
The recipe for diabetes: fat, sedentary, and unlucky.

Do you really want to just keep relying on your luck?

Anyhow, what worked for me was FEAR.
I changed my diet overnight and added some daily exercise.
I try to ride my bike 3.5 miles to work.
I find walking a few miles is actually really good too.

The hardest part for me is controlling my appetite.
Being fat.. is part way down the road to diabetes, and it has a vicious circle where being fat messes with your appetite and satiety regulation. The worse it gets, the more it gets worse.

Appetite control is key.
Find out what time of day you get hungry and take steps One Hour before that.

For me, sugar free Metamucil fills my belly without calories, and it really helps.
Then a small satisfying snack to put an end to the munchies.
I use a bit of cheese or a tin of kippered herring.
The fat content really helps kill the hunger.

Read Gary Taubes "Good Calories, Bad Calories" for another take on the bad science behind the low-fat bandwagon.

It is well known that farmers use grain to fatten cattle, and corn to fatten hogs.
That is - they fatten them up using a low-fat/high-carb diet.
Draw your own conclusions.