I lost 40lbs in 12 months while working. I did a bodyweight routine at home 4x a week for 30 minutes and calculated calories in and out. 4 months in, I eyeballed everything.
I was a pretty experienced athlete in high school/college, so I knew the basics well and knew if I worked at it I'd lose it, so that helped a lot, but I didn't do anything magic.
But the point is, you changed your lifestyle, and stuck with it. I think most who lose weight put it back on because they don't change anything. As if being thinner makes bad food less bad :)
I was a pretty experienced athlete in high school/college, so I knew the basics well and knew if I worked at it I'd lose it, so that helped a lot, but I didn't do anything magic.