Wherever I go, people always want to talk with me about the blog. Lately, I’ve heard a lot of this: “I went to your website and saw a lot of interesting stories, but I didn’t know which ones to read first. Where should I start? What is the first thing you would want me to understand?”

There are two things I want everyone to understand: First, there’s a big difference between real food and manufactured calories. And second, manufactured calories cause all kinds of serious medical problems, like diabetes and obesity.

So today I want to take you on a field trip. We’re going to step out the back door, and into a field of wheat. Pick a single grain, and take a good look at that grain. What do you see? Each and every grain contains 1) a bran fiber coat; 2) an endosperm, composed primarily of starch; and 3) the wheat germ, where the nutritious oils are. If you strip away the bran coat and wheat germ, as we humans figured out in the past two hundred years or so, all that’s left is a pellet of white starch. This is also known as white flour.

Now, if you could look at that pellet of white starch under a microscope, you would see a long, simple chain of sugar molecules. Our bodies are able to break the links between those sugar molecules so efficiently that when you eat white flour, your blood sugar rises as fast as — if not faster — than when you eat sugar straight from a sugar bowl. How do I know this? I learned it from my diabetic patients who check their blood sugars after they eat. White flour and sugar both spike blood sugar.

You may have heard white flour and sugar referred to as “refined” carbohydrates. According to the dictionary, to refine is to remove coarse impurities. The term “refined” was selected to intimate that whole grain flour was coarse, or unrefined. With rare exceptions, like honey and maple syrup, refined carbohydrates are not found in nature. In nature, carbohydrates are almost always found attached to fiber. Consider dates and beets, for example. Both of these are used by industry as raw material for the manufacture of sugar. But in their original state, they are so rich in fiber and phytonutrients that they are considered superfoods.

When you eat, your gut breaks down food into sugar, which is then absorbed into your bloodstream. When foods are easily broken down (like white flour and sugar), absorption is quick and blood sugars rise rapidly. When food is broken down slowly (like produce, nuts, whole grains, beans, eggs, meats), it is absorbed slowly so that blood sugars remain more or less stable.

After food crosses the walls of your gut to enter the bloodstream, the body releases insulin to catch the incoming sugar and escort it to the cells of your body. The insulin is manufactured by your pancreas.

Here comes the most important part of this explanation: The more quickly you absorb sugar, the more insulin you need to escort it to its destination. The more slowly you absorb the sugar, the less insulin you need. This works like a valet service. Imagine you were invited to a huge party, and the invitation said to arrive at 7 pm. So at exactly 7 pm, 1000 cars show up at the party center, in which case there will need to be a great many valet staff to park those cars.

But let’s consider another scenario, one in which you receive an invitation to an open house from 3 to 9 p.m. At the end of the day, the party center will still park 1000 cars. But they won’t need nearly as many valet staff.

The sugar is the cars, and the insulin is the valet staff. If all the sugar shows up all at once, you’re going to need a lot of insulin. But if the sugar gets absorbed bit by bit, you won’t need nearly as much insulin. The more insulin you use, the higher your levels go. The higher your insulin levels, the more fat you store in your belly. Insulin is a fat-storage hormone.

Which nutrients do we absorb slowly? Fiber, protein, fat. Think whole grains, dates, beets, avocados, peanuts, eggs, beans, fruits, vegetables. Which ones do we absorb quickly? Stripped carbs such as cake, sugar, breakfast cereals, doughnuts, bagels, cookies. Is it starting to make sense?