Fasting. I started gently at first, 12 hours fasting, 12 hours eating window for a week (12:12) to ease into it. Then I went up to 13:11 for a week, then 14:10 for a week, and now I'm on 15:9 which is where I'll probably stay. I use the Fastic app to help me track it.
As others have said about fasting, the hunger passes quickly, after the first few days. It has reset my relationship with food and I have realised I was eating food first thing in the morning and grazing all evening up until bedtime as a habit rather than actually needing the food or even feeling hungry.
I genuinely don't feel deprived at all. I eat and drink whatever in my current window of 9 hours. E.g. I had an Indian the other night when the family had one, I had a glass of wine last night because my OH had one - I'm not having to say 'no' to things or cut out food groups etc.
The weight loss has been gradual, I'm probably losing 2 or 3 lbs a month, but I think that's because it's a sensible and easy to maintain way of life, rather than a restrictive crash diet.
It has honestly been game changing for me.