1. One was not eating breakfast, this works well when I'm in the office. Then you have fasting built into your daily routine. This has many metabolic benefits.
2. Switching to a low carb diet (keto). I never thought I'd quit eating bread, but reducing carbonhydrates (esp. sugar) and eating more eggs & meat had the biggest effect on my weight. More so than doing sports. This is just a rough guideline, I don't follow this very strictly.
3. Sports + Fasting: Sometimes on the weekends I go on a hike or do some sports and only eat when I get home in the afternoon (e.g. steak). This forces my body to take the energy from the fat reserves.