The Ten Best Diet Foods in Existence.

What you eat and what you eat will have a big effect on how quickly you take off pounds, and more importantly, how long you keep those pounds off. There are certain foods that you really should be eating on a regular basis, for lots of good, healthy reasons. They come from all food categories, but every one of them has one thing in common: they pack a lot of nutritional punch into their calories. Here's a list of five diet foods that will help you stay healthy and lose weight.

1. Whole grain breads

If you've been paying attention, you know that evil carbs are the current diet buster. If you just stay away from all carbs, some of the diets proclaim, you'll lose weight no matter what else you eat. That's not only wrong, it's downright dangerous for both your health and your diet. There's a reason that the Bible refers to bread as 'the staff of life'.

Instead of cutting out carbs, you should be aiming to reduce them to a healthy portion of your diet - which most doctors agree is about 50-60% of your caloric intake. That means that if you're on a 1500 calorie a day diet, you should be striving to get about 900 calories a day from grains, fruits and vegetables. Whole grain breads pack a lot of nutritional value. Replace your two slices of white toast with 1/2 a cup of oatmeal or whole grain cereal, and for about the same number of calories, you'll be getting three times the vitamins, amino acids and roughage that your body needs to function. You'll feel full far longer, too - because you've given your body something to work on that will take a while to digest.

2. Fish

Eat at least three servings of fish per week, say many major medical associations. Fish is low in fat, as high in protein as red meat, and provides something that most other proteins don't - omega 3 fatty acids. Omega 3 is one of the main building blocks in your cells. If your body doesn't get enough Omega 3, it will try to build cells from other fatty acids. The problem is that those cells are not as flexible, and not quite the right shape. Among the cells that aren't quite right are the ones in your brain that help control impulses and tell your body what it needs. By providing enough Omega 3 for your body to use, you'll be healing the damage done through years of poor diet. And since fish, as a general rule, has fewer calories than most meats, you'll be saving calories, too. Just remember that you're REPLACING portions of meat with fish, not adding them to what you already eat.

3. Spinach

At 13 calories and 2 grams of carbohydrate in 2 cups of chopped raw spinach, this is one of the lowest cost sources of nutrition you can give your body. Every serving gives you folic acid, manganese, beta-carotene, protein, lutein (a potent anti-oxidant), magnesium, vitamin C and vitamin K. You can eat it raw in salads, steamed as a side dish, or sautéed in a tiny bit of oil for a different taste, and still get all the nutritional benefits.

4. Olive Oil

Your body does need a little fat to process vitamins and use them properly. Olive oil is a mono-unsaturated fat that is the primary source of fat in the so-called Mediterranean diet. It contains antioxidants, flavonoids, beta-carotene and vitamin E, among other things. One tablespoon has a whopping 125 calories, but drizzled on a 13 calorie spinach salad with a little lemon juice and some garlic, you still have a meal with less than 150 calories - and a whole lot of healthy fuel for your body.

5. Pink Grapefruit

With only 40 calories in half a grapefruit, you're getting 45 mg of vitamin C, lycopene, pectin, beta-carotene and potassium. It's versatile and tasty. Eat it as is for breakfast, or toss it into a salad with spinach for an extra punch to perk up the nutritional quality of your diet.

Most importantly, don't base your diet around any single ONE ingredient. The best way to lose weight is to eat a healthy variety of foods to make sure that you get all the essential nutrients that you need each day.