It's very very easy:
No, don't cut THAT much out. Look, want to lose three pounds? Stop eating ketchup with your dinner.
Want to drop seventy pounds? Skip that baked potato or Snicker's bar every day.
The difference between fat and thin is an ABSURDLY small amount of food. I mean it. Absurd.
As previously mentioned, a tablespoon of ketchup every day is worth three pounds over the long haul. A baked potato seventy. How on earth is this possible?
Well, while it takes a lot of calories to create a pound of fat (Around 3,500), it takes very very few to maintain it (2-8, depending on gender, activity level, blah blah blah - I'm using 4 because that's my number, as experimental evidence has demonstrated for me).
Weight is built up and lost over long periods of time; it would take three years for me to stabilize on a weight for a given consumption and activity level. It can take you between one year and six. Don't expect to be done overnight. You'll see dramatic results over months, but it -will- be months. Weight loss is a very tiny lifestyle change, smaller than anybody will tell you.
You want to lose weight and keep it off? It's not difficult. It's just not what everybody tells you; it took me losing fifty pounds before I realized the difference between what people tell you weight loss is, and what weight loss really is.
Getting fit, of course, is an entirely different proposition. Being your ideal weight and being able to run a mile without getting out of breath are two completely separate things.