According to the latest research, the only way to lose weight and keep it off is to do it slowly by permanently changing your eating habits.
In other words, don’t crash-diet.
Otherwise, you’ll only put it all back on again—probably with interest—and likely slow your metabolism and deplete your hunger-stopping hormones for years to come.
If that happens, you’ll find it impossible to lose weight again just by cutting calories. Then, the only way for you to keep the fat at bay will be to live a life of always being hungry.