That's why cold turkey isn't good. When you go too hard too fast, it's hard to maintain that momentum. So you end up gaining back what you lost.
What I did was I started counting calories. There's plenty of free apps like MyFitnessPal, that do a decent enough job. Enter your age, height, weight, and how often you exercise and based on your weight loss goals, it will tell you how many calories you need per day to lose weight.
In my case, I wanted to lose 2 pounds per week (which is a lot), so it recommended that I stay below 1800 calories per day. Since I was eating 3 meals a day, that left me with 600 calories per meal. I didn't make drastic changes like completely changing what I ate. Instead I just ate less of what I liked, in order to meet those numbers. So for lunch, I might go to taco bell and get only a Mexican Pizza, which is 540 calories.
You should still add healthier foods over time, but the long term goal should be sustainability. Things that you can continue doing, even after you meet your goals.