One that doesn't include "quickly". In order to maintain any weight loss, you'll need to maintain healthy habits for life. Research has documented that all too often, dieters will reach their desired weight, stop dieting, and return to their old weight (or even heavier) as they again indulge in an unhealthy lifestyle that made them what they were. Your best chance of success is to gradually adopt a sustainable, healthy lifestyle, which you can and will be able to maintain for the rest of your life.
Slowly but surely:
Begin by cutting out junkfood- cookies, chips, candy, soda, cakes, pie, donuts, dressing, butter, gravy and the like. Replace this with fruits, vegetables and 100% whole grains. Don't restrict your portions of fruits, vegetables or whole grains- always eat these if you are hungry.
Eliminate any product listing trans-fats or hydrogenated oils on its label ("partially-hydrogenated soybean oil")
Eliminate fried foods.
Derive your protein from lean sources, such as soy, grilled/roasted turkey, grilled/roasted chicken, skim milk or fish.
Eliminate white flour. Replace with whole grains. Any product listing "enriched wheat flour", "wheat", "wheat flour" on its ingredients should be substituted with one containing entirely whole grains. Replace white flour bagels, waffles, pancakes or bread with their 100% whole grain counterparts. Manufacturers can be tricky and might tout a product as "whole grain" even though it contains a large amount of enriched wheat flour- read the ingredients to be sure!
Eliminate "adulterated" foods. Foods containing unnecessarily added sugars, fats or salt should be replaced with their wholer constituents. Instead of canned peaches in syrup, choose canned peaches in water, or frozen peaches (no syrup).
Many seemingly healthy breakfast cereals (such as Special K) contain less fiber and almost as much sugar as Fruity Pebbles! Choose high fiber, whole grain cereals with minimal added sugars.
Eliminate dairy fat, which is largely saturated. Choose fat free versions of cheese, cream cheese,yogurt and sour cream instead. Eliminate cream.
In the end, you'll be left with a diet high in fruits, vegetables, whole grains and lean protein, low in saturated fat and cholesterol, high in omega-3 fatty acids, monounsaturated fats, and fiber.
As for exercise, follow the American Heart Association's recommendation of at least 60 minutes of cardiovascular exercise a day for those looking to lose weight. You'll probably need to work up to this- start with just 15 minutes or so of jogging on the treadmill or biking. Gradually increase the duration of your workout until you reach your goal.