Quitting oily and junk food started showing me results in about 2 weaks. The easiest way to quit eating junk food is to keep it out of your house. If fatty, greasy, salty or sugary foods aren't easily accessible, you're much less likely to eat them. Replace them with healthier alternatives, such as fruits, vegetables, air-popped popcorn and low-fat cheese, so you have snacks on hand when hunger does strike. Keep an apple, granola bar or package of almonds with you at all times. You'll have a healthy snack and be less likely to head for the drive-through or convenience store if you get hungry. Research restaurant menus and nutrition information online before eating out. Choose a low-fat entree and low-calorie beverage before you arrive. Making these changes for six to nine weeks can help you eat healthier for a lifetime. If your diet contains too much sugar, you have a higher chance of weight gain and tooth decay, try avoiding it. Too much sodium contributes to an increased risk of kidney disease and high blood pressure, make sure you keep this in mind.