The best tip, but as a Masters athlete the hardest to achieve! Best is don't get fat to start with if you can!
Each time I've put on weight the last couple of years - 2014 Broken collarbone with complications and 2015 6 months no riding with minimal exercise whilst caring for my wife through chemo it's been a real struggle to drop the kg's afterwards.
After the collarbone, it was a good 6 months and finally an 11 day solo bikepacking trip that finally got me back to ideal weight. Now I'm back on the bike commuting, it has stopped the weight from continuing to rise but not enough to drop it more than a kg... Already reducing calories, looking like I'll need to up the km's and back running if I can manage the niggles!