A few lifestyle tools you may, or may not, find useful.
1) Record your favourite TV shows and only allow yourself to watch them while exercising. That doesn't mean hours of press-ups, it might just mean walking on the spot, leg lifts while seated, or even simple isometric exercises. It's about associating exercise rather than food with reward as much as bumping up your exercise and fitness.
2) There are lots of entertaining podcasts out there. Load up your phone, get yourself a decent coat (at this time of year) and get out and walk. It doesn't have to be fast, just get out there and walk. If you struggle to find anywhere nice to walk locally consider getting a bus or train to the nearest park. Getting out among the green stuff really does help.
3) Start eating a lot more fruit and veg. Don't worry about how much (unless you're eating a lot of bananas, which are stuffed with calories). They won't stop you wanting the exciting stuff you crave, but they will leave less room for the junk and start making you healthier from the inside. My secret weapon while cutting back is to make a soup with all sorts of frozen veg, then thicken the water with a packet soup. Filling and tasty.
4) Accept that food will always be a potential problem. It is the easiest, cheapest, and most instantly gratifying way of cheering ourselves up. And I say that as a relatively skinny bloke (by modern standards) who regularly loses weight to keep on top of my bad eating habits. I am no exercise freak or gym bunny! Our bodies are simply not designed to deal with modern food availability and marketing, and unless you have a deeply rewarding and fulfilling life on all levels, it's very easy to let food cheer us up.... albeit briefly and mistakenly.
5) Be careful about taking advice from the internet.
Good luck. It'll be hard, but you can do this. You just have to want it enough... which is the hardest part.