Having Chocolate Milk instead of Coca-Cola.
Ordering a Hamburger without the Cheese and Bacon.
Having Red Wine instead of Beer.
Packing a healthy lunch instead of eating out for lunch (most fast food places that cater to the 9-5 crowd don't serve healthy food as its often deep fried).
Having juice instead of a high-sugar energy drink.
Ideally what you want is to pick foods higher in fibre / protein / nutrients / minerals and lower in sugar.
While it is true that to lose weight, a dieter will want to eat less than he or she is burning through exercise and daily activities, it's important to make quality food choices so you are getting more of the good stuff and less of the bad stuff. On the most basic level, a calorie is a calorie regardless of the source, and that yes, you could eat 1000 calories a day in pizza, fill up on water, and lose drastic amounts of weight - getting all your fibre / protein / nutrients / minerals from pizza isn't really a healthy way to do it.
Weight loss is about more than just keeping the calorie count lowered. Eating healthy is a lifestyle change that will take work, by figuring out how to make every calorie burn efficiently in your body.
Take the pizza as an example. It has refined sugar in the white flour crust, saturated fat in the greasy cheese, and any meaty topping is sure to be high in sodium and fat. These foods are not helping your body for a long term slow releasing energy burn, digestive help, or assisting with lowering blood pressure and preventing illness and disease.
A slice of plain cheese pizza from a walk-in shop is roughly 600 calories. 600 calories is a lot when you are making every calorie count. And if you are only eating 2 slices per day (and that is your entire diet) then you will end feeling very hungry.
Instead of having the slice you could have:
-A bowl of mixed bean salad (1 cup) 200 cal
-With a side of 1% cottage cheese (1/2 cup) with 1 Tbsp of ground flax seed 200 cal
-Steamed vegetables (1/2 cup) 50 cal
-5 Brazil nuts 100 cal
-A small apple 50 cal
That way you would be getting a larger amount of food, not feel hungry all the time, and still have a lowered amount of calories. Eating foods with lots of fibre, nutrients and so forth help you to feel full without starving yourself.
Note that the amount of food mentioned above could actually be two meals! It contains much leaner proteins, complex carbohydrates, fruits, vegetables, dairy and healthy fats. Your body will be able to use this much more effectively than a slice of pizza ever could!
It just goes to show that while calories should be reduced to lose weight, healthy choices are still very much a part of making healthier choices.
Of course sometimes you still want to treat yourself, and that is where things like chocolate milk come in. Yes, its a treat, but its high in calcium and protein.