This article was excerpted from Digestion Connection by Elizabeth Lipski, Ph.D., and provided by our partners at Rodale News.

Food is our most intimate contact with our external environment. What we eat, digest, absorb, and assimilate becomes us. However, we tend to overeat more often than not. And to make matters worse, we also eat nearly half of our meals at restaurants or as takeout meals. If you're like the average American, more than half of your calories come from highly processed, poor-quality, nutrient-poor foods—instead of organic, whole foods. It's like fixing your home with the shoddiest materials possible. Here are some eye-opening facts about the average American's diet you need to know.

1. Flour and cereal products comprise 23 percent of our calories every day, nearly all of which (89 percent) are refined. That means that they've lost most of their vitamins, minerals, essential fatty acids, and antioxidants. Refining of grains can affect blood-sugar levels and lead to inflammation throughout the body.

2. We eat 17 percent of our calories from refined table sugar and high-fructose corn syrup. The current estimate is about 496 calories a day and more than 22 teaspoons. Of course, it takes B vitamins, magnesium, chromium, zinc, and other nutrients to metabolize and use these sugars, but there aren't any of these nutrients present in refined sugars, so your body has to steal them from somewhere else.

3. Twenty-four percent of our calories come from fats and oils, most of which have been highly processed and stripped of antioxidants, vitamins, and minerals. These are "junky fats" that have been denatured, oxidized, and structurally damaged. They're found in nearly all of our packaged and processed foods and in most of the vegetable oils that we buy.

4. We eat only five percent of calories from fruits and vegetables. Fewer than one person in four eats at least five servings of fruits and vegetables a day (about two and a half), even though they protect us against heart disease, cancer, diabetes, and most other illnesses.

5. The average American also eats a dearth of nuts each year—only 15 ounces. Most of the ones they do eat are on or in pastries. Nuts have been shown to support heart and brain health and generally be terrific for us. (Nuts are also linked to a lower risk of pancreatic cancer and act as a natural weapon to protect your health in these five other ways.)

More from Rodale News:
The 8 Best Foods for Your Gut
Control Your Cravings With This Gut Trick
The Natural Ingredient That's Wrecking Your Gut