Perfection isn't sustainable.
This is a truth that many of us have had to learn the hard way, mostly from failing multiple diets again and again.
The real way to take the weight off (but more importantly, lower our body fat) for good is progress, not perfection. If we improve our habits by just a small amount each day, in time it will add up.
Look at it this way. If you haven't ran in ten years and decide to run a marathon, you woudn't start day one by trying to do the full marathon. If you did, it's almost guaranteed you would fail and probably injure yourself. Instead, you would start just by running for 5 minutes. Then 1 mile, increasing to 3, 5, 10, and so on until you've built up enough endurance and strength to complete that full marathon. The same can be said about nutrition.
Take it slow, be better than you were yesterday, and before you know it you'll be seeing awesome results and feeling proud of what you accomplished.