Every single food we eat impacts our bodies, well beyond keeping us fueled. Carbohydrates, for example, get digested and broken down into glucose (or blood sugar) and then used as fuel in our cells. Since carbohydrates are the body’s main source of energy, a hormone called insulin comes along to open the door of our cells and let the glucose in to feed them. With more cells being fed, less glucose remains in our blood. That's when everything works well.

Carbs are not all packaged the same, however. Simple carbs like sugar and pasta break down quickly because they come in packages of shorter molecules. This can create a spike in blood glucose, giving you a burst of energy often called a sugar rush or sugar high. You'll find simple carbs in sweet desserts, processed foods, candy, and sodas, but whole plant-based nutritious foods like fruit and vegetables can also naturally contain carbs, but most are made up of healthier carbs called complex carbohydrates.

When You Eat Complete Carbs It Takes Your Body Longer to Unlock the Fuel

Complex carbs are just that, more complex, meaning made up of longer molecules. They are made up of groupings of simple sugars all strung together, which take our digestive system longer to pull apart (think of untying a knot in your shoe versus a bow). Since the digestive process takes longer, complex carbohydrates steadily increase blood sugar incrementally, instead of all at once. This creates a longer and more lasting flow of energy. Most fruits and vegetables fit into the complex carb category, along with foods such as legumes, pasta, and bread.

New research shows that even when you eat carbs as part of a meal, you can prevent blood sugar spikes, just by adding salad greens to your plate.

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What Cause Blood Sugar Spikes And Are They Bad?

Individuals who are pre-diabetic or have diabetes should constantly be checking their blood glucose. They either don’t produce enough insulin or they deal with “insulin resistance.” That is when your body doesn't respond well to insulin, which prevents sugar from entering the cells to be used as fuel. This causes your blood sugar to remain high, also referred to as hyperglycemia.

When you deal with hyperglycemia, over time it can start to damage your blood vessels which then increases your risk of heart disease, stroke, kidney disease, vision problems, and even nerve problems. So what about people that don’t have diabetes or aren’t pre-diabetic? Are blood sugar spikes bad? The fast answer is yes.

High postprandial blood sugar (after a meal) can create oxidative stress, which increases inflammation, damages those blood vessels, and increases the cardiovascular risk even in those that aren’t diabetic. A 2018 study published in PLOS Biology suggested that people who tend to have “normal” blood sugar ranges could still have patterns of blood sugar levels that increase their risk of becoming pre-diabetic or diabetic down the road.

In the study, researchers measured how the participants' blood sugars changed throughout the day instead of using the two common blood sugar tests — fasting blood sugar and HbA1c, which is a measurement of the average blood sugar level over three months. The results found that almost one in four participants had a post-meal blood sugar spike that falls in the diabetic or prediabetic range, even though they would typically be normal on “common” blood sugar tests.

The takeaway from this study was the total carb count wasn’t the culprit in causing those blood sugar spikes, but rather a combination of things. For instance, when given a meal of either cereal and milk (54 grams of carbs), a meal replacement bar (48 grams of carbs), or a peanut butter sandwich (51 grams of carbs), 80 percent of those who consumed cereal and milk had a blood sugar spike that placed them in the prediabetic range.

The cause? Cereal and milk contain a lot more sugar (35 grams compared to 12 grams for the sandwich and 19 grams for the bar) and a lot less fiber (3 grams compared to 12 grams for the sandwich and 6 grams for the bar).

Smiling young woman chopping vegetables on cutting board in yard
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Why Fiber is So Beneficial, and How It Can Keep Blood Sugar Steady

Think of fiber as your body's “roughage,” which fills you up but keeps blood sugar steady. It’s a type of carbohydrate that can’t be digested and helps to regulate how our body uses sugar. You find it in more of those complex carb foods including whole grains, fruits and vegetables, legumes, and nuts.

A recent 2021 study published in a respected journal, the Recent Patents on Food, Nutrition & Agriculture, determined that the fiber content from salad vegetables was beneficial in keeping glucose rates from skyrocketing after meals. The researchers tested red oak leaf lettuce, red coral lettuce, green oak lettuce, butterhead lettuce, and romaine. The results found that the fiber content of these lettuces inhibited specific enzymes that are important in breaking down carbohydrates. When these enzymes are inhibited, the rate and extent of glucose absorption is reduced, which prevents hyperglycemia, so blood sugar stays low.

Although more research needs to be completed on human studies, there is nothing harmful about adding a leafy green salad to your meal to help keep your blood sugar stable. Better yet, turn it into your entire meal with the addition of healthy fats from olive oil, nuts, and seeds and protein from beans, lentils, or tofu.

Bottom Line: Even if you have a big meal, don't skip the salad. It will do you good.

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