Skip the supplements and fads. Do it the life-lasting way - increased exercise and increase your intake of filtered water.
Brisk walking for 5 hours a week doesn't cost anything. Over the course of a month it will make a difference, and it is something you can do anywhere and do all your life.
Watch the medications if you take any. Many prescription medications, especially antidepressants and similar, can cause weight gain.
30 years of fighting weight - 15 of those years not doing so wisely - the last 15 successful with the exercise route.