If you have 4 stone to lose it seems a daunting process. but if you stop thinking about the end goal and break it down to 2 pounds at a time, or half a stone at a time, it makes it easier.
Don't go on a diet. If you go on a diet at some point you go off them. You have to change your habits forever, lose the bad ones, establish the good ones. I used to be an all or nothing person. Go on a diet, slip up and then say, what the hell I've blown it, and eat more. Take the long term view. Don't put a time limit on loss, for a holiday for instance. Eat healthily in the main, with the occasional treat. If you have overdone it one day, pull it back on the next, until eventually the good days overtake the bad.
If you change your eating habits over a long period of time your taste buds change. I have not eaten chocolate for 3 years. I have not denied myself it, I no longer have a sweet tooth, although I like an ice cream or cream tea every now and then. It then becomes easier to maintain a stable weight.
There are no good or bad foods, it's your attitude to them. All food is fuel for the body, but some of it is better than others. Choose the better fuel most of the time, and don't overfill the tank.
Exercise. If you hate gyms, walk for 20 minutes, build it up. Put music on, dance like a crazy woman for 20 minutes. You sweat but it feels good. Check out free videos on You Tube. Jessica Smith and Lucy Wyndham-Read put out a lot of free content if you want to exercise at home.
Losing weight is ultimately a mind game. You are given one body, it's your most precious thing, treat it well and do your best for it and it will do it's best for you. All I know is that consistently eating well and moving more most of the time has reaped dividends for me. Niggly little ailments have cleared up, I feel more positive about life, I now have options I didn't have before because losing weight has opened up opportunities for me. I am not afraid to make a stand or be heard, or get noticed. Before I kept my eyes to the floor metaphorically and now I am eyes wide opened and fully engaged.
A bit of an essay, but a PP did ask.