You probably already know that diabetes and obesity in the United States have reached epidemic proportions, but you may be surprised to learn that many, if not most, cases of diabetes are preventable. How? The best strategy for preventing diabetes and obesity is to learn how to conserve your body’s insulin supply.

Think of your insulin as an escort service that catches the glucose (sugar) arriving from your gut, and then escorts it to the cells, opening doors to transfer that sugar into your cells. The more rapidly food is absorbed into your bloodstream, the more insulin you need to catch it. If and when that happens, a healthy pancreas says “that’s OK, I’ll make more!”

Simply releasing more insulin is not as reasonable a compromise as you might think. Even though you can’t live without it, elevated insulin levels create their own set of problems. For example, insulin is a fat-storage hormone: the more insulin you release, the more fat you store, especially in your abdomen. To make matters worse, the more fat you store in your abdomen, the less efficiently your insulin works. Then it takes more insulin to get the same job done. This vicious cycle is called “insulin resistance.”

High levels of insulin cause other serious problems. Having high insulin levels makes you hungry because insulin coats the receptors in the satiety centers in your brain. That makes it hard to tell if you are full. So if you’ve had the experience of cruising the cabinets after dinner, looking for something else to eat, that may be why. Sustained, elevated insulin levels cause numerous other significant problems, like high blood pressure and polycystic ovarian syndrome, which interferes with fertility in many young women. So it makes very good sense to conserve your insulin.

When you eat a food that is broken down quickly and absorbed rapidly, your pancreas releases a large bolus of insulin to catch it. But if you eat a meal that is more slowly absorbed, the insulin is released one drop at a time, so very little gets wasted. It takes just a thimbleful of insulin to catch sugar that is arriving bit by bit. How does that work? Like a valet service.

Imagine that your insulin is a valet service, and the sugar (absorbed from the food you eat) is the cars. If 1000 cars arrive all to a big party all at once, say at 7 pm, the boss is going to need to hire a lot of staff to park all those cars. But what if they have an open house instead, with the arrival times of those same 1000 cars spread over a few hours, say from 3 to 9 pm? Fewer valet staff will be required to get the job done.

In both cases, 1000 cars will be parked. But if they arrive slowly, it won’t take nearly as many valet staff to do the job. It’s the same with your insulin and sugar. If you choose foods that are broken down and absorbed slowly, it won’t require nearly as much insulin to transfer the sugar into the cells.

Another thing about insulin is that you set up a vicious cycle when you waste a large amount first thing when you wake up in the morning. So if you need to release a ton of extra insulin because you chose a breakfast loaded with stripped carbohydrates, your sugars and insulin levels will seesaw all day long. If you eat toast and jelly, or breakfast cereal, your pancreas will release a massive amount of insulin to manage that sugar spike. The insulin will overshoot the mark and cause your blood sugars to plummet. That won’t feel very good, so you’ll go find something to bump your sugars, which will raise your insulin levels again. And so on. Eat two hard-boiled eggs, with or without pesto, and that won’t happen.

If your pancreas continues to be called upon to meet an excessive demand for insulin, year in and year out, the day may come when your pancreas has difficulty keeping up. If this happens to you, then your blood sugar levels, which rise normally (and temporarily) after eating, will slowly begin to rise higher, and then take longer to return to normal. That’s because if there isn’t enough insulin available to escort incoming sugar to hungry cells, then the sugar has to float around in your bloodstream, waiting until more insulin shows up.

To add insult to injury, high blood sugars themselves negatively affect your pancreas and decrease its ability to make insulin. So once your pancreas begins to struggle to keep up with demand, you enter a negative feedback loop of worsening blood sugar control from which there is no exit unless you start conserving insulin, whether with diet, exercise, or medication. Or you can just start now.

Remember that you’re not alone — this problem belongs to all of us, and it’s been getting worse for decades. In fact, the standard American diet (sAd) requires so much insulin that it is overwhelming the insulin-producing capacity of millions of people. Who are they? Everyone with pre-diabetes and Type 2 diabetes, even those who don’t know they have it.

What can you do about this? You can be kind to your pancreas and your insulin supply by learning which kinds of foods are absorbed rapidly and which are not. You can learn how to tell the difference between real food and manufactured calories.