Literally just fix your diet. You don't even need to work out in order to be 80kg ish, unless there is something really fucked with your metabolism. I only recently got intondoing actual workouts, since I was tired of being skinny-fat, but even then I considered my shape to be average enough.
1) Drop all fucking sugar you can find. Energy drinks? Out. Sweetened tea? Out. A snack in the evening? Out. Frosted flakes? You better believe it out. If you want to go a step further, drop ketchup and other similar things that are full of sneaky sugar. At the very least stop using Heinz.
This alone should do wonders considering your current state.
2) Cut all fast carbs. Pasta? Out. White bread and buns? Out. Any sort of cereal? Out.
This is where I am at as I am a bit lazy to go through the next steps.
3) Cut the fat intake. First and most obvious is non-home-made meats, eg sausages. Also in general try to cut all prefab foods. Then, if you do home-cook your meat, do it without oil or butter, aka no frying.
4) Most advanced stage, eat good food. This means REAL greens. Peas, spinache, broccoli, try to find something that you find ok tobeat from those. If you are lazy you can opt for chilled vegetable mixes at the store. Try to eat them along your other meals.
All in all just the first two should do wonders for you as I said. Though I'd also advise some light exercise like going out for a walk for an hour.