My brother was 170 lbs when he graduated high school.
He started taking medicine for anxiety in college and he gained 108 lbs on it. He was at 278 lbs when he decided to come off of the medicine.
In 5 months he dropped 60-70 lbs. He maintained his weight at about 210 lbs for about 6 years. He downloaded the MyFitnessPal app and kept track of everything he ate. In 6 months he lost another 45 lbs.
He weighs 165 lbs now, less than what he weighed in high school, and he's 14 years older. He did not exercise, he just ate sensible. He had cereal for breakfast, a snack 2-3 hours later, subway or something light for lunch, another snack 2-3 hours later, a descent dinner followed by another snack.
I've never seen him happier.