I lost 55 pounds in 4 months. I simply started eating healthier by taking note of what I eat and how much I eat.
An average human being burns around 1800 calories a day by simply being awake and breathing (slightly less if you’re skinny, slightly more if you’re heavy). Once you know that, losing weight is incredibly easy.
In those 4 months I made sure I never ate more than 1400-1600 calories a day, usually slightly less than that. This means that without any additional exercise, I was burning 200-400 calories a day more than I was eating. If you then consider the fact that a pound of fat = 3500 calories, I was losing a pound every week and a half.
In theory, exercise is not a requirement to lose weight. I personally did start running when I started eating healthier, mainly because I wanted to get some stamina. I went from dropping dead after running for half a minute, to running for an hour straight (± 7 miles). It did help me lose weight a lot faster (At one point I was losing 3-4 pounds every week), but it’s not a requirement. Also note that muscles way more than fat and also burn more calories than an average human (if you do powertraining and have some musclemass, you’ll burn more than 1800 a day just by being alive).
Right now I’m on hold due to the winter and the holidays. I intend to stick to the weight I currently have until Spring, and then start running 3 times a week again as well as mind my calorie intake again. I would love to lose another 10-15 pounds in order to be in the “safe zone”.
All in all, don’t let all the dieting and exercise scare you. Losing weight is as easy as gaining it. I still eat fries, hamburgers, meat, pizzas etcetc (one thing I did completely drop, though, was soda).

