I've tried many fad diets and supplements over the years, eating one meal a day, vitamins, low carb, intermittent fasting, etc.
The one thing that had the biggest impact, the only thing to have an immediate, significant impact was beginning to only drink water--no soda pop (even diet) no juice, no milk (except with the occasional Oreo). I drink at least two liters of water a day and feel so much better.