Weight Watchers. It worked because I put in the effort. You learn to prioritize. You can have your cheesecake, but you have to eat carrot sticks for the rest of the day.
I don't think I need to diet now, but when I was traveling in Australia I lost 8 kg. I had a backpack, was traveling, surfing, and went to the Outback, where it's really hot. It was so physical.
I tried Weight Watchers and I lost 12 kg, but in a few months I got everything back. Then I tried a new age diet. That changed my attitude to food. I only lost 2-3 kg but my weight has been stable since then.
I went on the Weight Watchers diet with my mum because she wanted moral support. After every weigh-in, we'd feast on Thai. Over the course of a month, I lost about 300 grams, but my mum lost 4 kg.
I did a vegan diet for 2 years, for the health benefits for running. The diet improves your sense of taste. Fast food kills it, but on the diet even vegetables tasted sweet.