I think long term, people who keep it off are those who've made exercise a hobby (be it sport, walking, gym or whatever).
Long term those that keep it off remain accountable and responsible for their calorie intake. More often than not they also tend to be active.
Peoples negligence when it comes to the energy content of foods is astounding and in my opinion the reason so many of the nation are overweight.
We eat what we want, rather than what we need. Whilst eating what we want can be encouraged, afterall food is to be enjoyed, if you do not exercise control and moderation then you are your own downfall.
The 80/20 rule for whole vs processed foods is a good way to satisfy cravings & desires without negatively affecting your health and ensuring you still have a nutrient dense diet. Equally ensuring a minimum of 10g fiber per 1,000 calories consumed forces fruit & vegetables in to your diet.
More often than not it's perceived as 'bad' to eat a few hundred calories of foods you enjoy every day but having a blow out which far exceeds that at the weekend as a reward for being good is considered fine... If you restrict foods from your diet that you want or enjoy when they are placed in front of you the majority of people do not possess the will power to not go off the rails and gorge. You can undo an entire weeks calorie deficit in one weekend blowout.
Edit: Another note. It takes 10 days for your daily average intake to reach the level of actual daily intake when reducing or increasing calories. For example, reducing from 2,500 calories to 2,000 calories, your 10 day moving average will not reach your current intake level until day 10 (thereabouts).
I would also recommend as suggested considering a 7 day moving average for your weight trend. This will smooth out any fluctuations in weight caused by meal timings, foreign foods and bowel movements/water retention
and avoid making unnecessary premature adjustments to intake.