For most of us, even when blood sugar skyrockets after a big meal, our bodies can bring it back to normal in a few hours with no problem. Only people with untreated diabetes have blood sugar levels that stay quite high most of the time.
Logically, for a long time, doctors thought that only those people needed to be concerned about the effect of food on blood sugar.
Now we know that even in healthy people, high blood sugar after meals can, over time, damage the body, even if it never causes diabetes. In short, it’s no longer just certain people who need to worry about their blood sugar; it’s pretty much everyone. It should concern you even if you’re thin and healthy, and especially if you don’t get much exercise (does that describe you? It describes most people) or you carry extra weight around your middle.
By now you’re wondering, “How can I get off the rollercoaster?” Take heart: It’s not that difficult — and we’ll show you how. Later, we’ll get into much more detail about how our diets contribute to unstable blood sugar (hint: foods like white bread, white rice, potatoes, and sugary drinks are major culprits) and which foods can help solve the problem. But for now, let’s take a deeper look at why you should care.
When you eat a big meal, especially one with a lot of starchy or sugary foods, the food makes its way through your stomach and intestines and then is converted into glucose, the main fuel for your muscles and even your brain. Voilô, instant energy!
But a big starchy meal can give the body more glucose than it needs. In fact, it can raise blood sugar levels twice as much as another, healthier meal would.
Most people’s bodies can bring blood sugar down fairly quickly, within an hour or two of eating. The body does this by releasing insulin, a hormone produced by beta cells in the pancreas. Insulin signals the body to let that blood sugar into cells to use as fuel and to store the rest in the muscles.
But if you eat a huge pile of French fries or a big piece of bread, your body has to deal with a serious flood of blood sugar, so it overreacts, pumping out too much insulin. If you’re overweight, it may pump out even more. All that extra insulin brings blood sugar down — too far. And it hangs around a long time, keeping your blood sugar low for hours. As a result, you can fall into a semi-starved state. Indeed, your blood sugar may be even lower than it was before you ate! Now you’re really dragging. Your energy is low. You may get a headache.
Your body recognizes that your blood sugar is too low, so it reverses course, spewing out hormones that raise blood levels of sugars and fats (the kind that could trigger a heart attack). Your brain also sets in motion signals that tell you that you’re hungry. Even though you ate more calories at lunch than you really needed, your blood sugar is so low that your body thinks it needs more food. Those doughnuts in the conference room sure look attractive right now.