Its relatively easy getting pumped and aggressively dieting or exercising for few weeks/months, and then later slowing down and gaining back all the lost pounds.
A habit that seems to be making a difference for me is consciously chewing food 2x longer than usual. I end up eating less food and have improved bowl movements.
That's why the modern method suggests you to take *small* but permanent steps forward. Cutting a slice of bread per week was easy. Cutting M&Ms was easy. Cutting soda cups to be 60% of what they were before was, well, manageable. Biking for 15 minutes 2x per week was easy. If you feel a step is too big then it's going to require a lot of willpower, so you try to take a smaller one. Over time you accumulate a ton of tiny gains and realize it all adds up to make a big difference.