I use a fitbit (activity tracker) and a free program called myfitnesspal (MFP), which uses data from the tracker to calculate how much you should eat to match your activity level, and meet your self-selected weight goals.
I've decided I want to lose 500g per week until I hit 83kg as this seems to be my healthiest weight, acknowledging that fitness and health is a much more holistic thing than just plain weight. And 500g per week is very achievable and doesn't require much of a lifestyle change.
I started in the week before Christmas at a bit over 93 kg. I am currently hovering at about 90kg. My main change is to snack less to stay under kilojoule limits advised by MFP. I've also been building a maimai (duck blind, for duck season) on a friend's farm near here. This involved several days of working in the hot, hot sun and carrying timber and other materials through paddocks. I have days when I don't care and just eat and drink what I like. This includes ALL of the Christmas and new year special family days. On the paddock days, I couldn't eat enough to make up the shortfall in kilojoules advised by the program and tracker.
I've still lost 3kg in a bit over a month.
It appears to work. Knowledge is powerful. Knowing what you eat and what you burn has a huge impact.
