What Is Low-Glycemic Eating?


When you make the wise decision to have some cauliflower instead of a cookie, you’re engaging in low-glycemic eating, the practice of keeping blood sugar spikes low with smarter, longer-burning carbs.

Both newspaper and lighter fluid are flammable, but throw each one onto a campfire, and you’ll get two noticeably different results.

Such is the case with low-glycemic (newspaper) versus high-glycemic (lighter fluid) foods, if we pretend that the fire is your blood glucose level.

The lower a food ranks on the glycemic index (GI), the less rapidly it will spike blood glucose levels after consumption, and vice versa.

What exactly are health-conscious consumers supposed to do with this information?

Let’s start with a breakdown of how different foods are ranked on this list.

The Glycemic Index

Pure sugar is at the top of the index with 100 points, and everything else is scored accordingly.

Researchers have assigned GI values to thousands of commonly consumed foods.

Here are a few examples, courtesy of Oregon State University:

  • Plain bagel – 72
  • Pumpernickel bread – 56
  • Unsweetened orange juice – 50
  • Oatmeal – 55
  • White rice – 89
  • Full-fat milk – 41
  • Banana – 62
  • Watermelon – 72
  • Black beans – 30
  • Peanuts – 7
  • Fettuccine noodles – 32
  • Sweet potato – 70

What Determines a GI Score?

Some carbohydrates are harder for humans to digest than others, which partially accounts for differences in GI score.

Foods containing fructose, for example, trend toward lower GI scores because the body processes this form of sugar less efficiently.

Speaking of processing, the extent to which a particular food is processed outside of the body is considered the most influential factor in determining GI score.

The more fiber, fat, and protein a manufacturer strips from a food product, the more severe the glucose spike will be.

One exception to this is watermelon, which has a high GI score of 72, according to the OSU table.

There’s no need to shun this beloved fruit, however, because watermelon has a very low glycemic load.

Glycemic Load vs Glycemic Index

In the case of watermelon, the high GI score (72 points) and low GL score (a measly 4 points) means that you will quickly arrive at a very small, easily manageable “spike” in blood glucose.

Like glycemic index, glycemic load is also dependent on the digestibility of the sugar, as well as the amount.

It’s very important that anyone recommended or ordered to follow a low-glycemic diet understand both of these concepts, as both speed and amplitude influence the severity of a blood glucose spike.

According to research, low-glycemic eating is important for diabetics, overweight dieters, and those at increased risk for cardiovascular events.

How the Glycemic Index Affects Different Populations

More than anyone else, the diabetic population is heavily concerned with the impact of glycemic index and glycemic load on blood glucose levels.

In fact, it was for diabetics that the index was first created in the early 80s, but unfortunately, the relationship between GI/GL and successful diabetes management is not as clear as it sounds.


A very large meta-analysis from the Harvard School of Public Health that reviewed survey data from more than 200,000 respondents over a 24-year period confirms the positive correlation between glycemic index, glycemic load, and type two diabetes incidence.

Per the study, “Those (participants) in the highest quintile of energy-adjusted GI had a 33% higher risk of T2D than those in the lowest quintile.”

It’s also important to note that participants in the highest quintile of GL had a 10% higher risk, and perhaps most importantly, that the combination of high GI/GL and low “cereal fiber” was correlated with a staggering 50% increase in type 2 diabetes incidence.

Still, the authors of this study noted that these connections between GI, GL, and diabetes incidence are still controversial because other analyses have found much weaker connections or none at all.


Metabolic syndrome, an umbrella term for several traits and conditions that increase risk for heart problems and diabetes, is closely correlated with GI, GL, and fiber intake.

This review from Tufts University in Boston found that metabolic syndrome incidence was decreased among participants in the “highest quintile of cereal fiber intakes” and increased in “individuals in the highest relative to the lowest quintile category of glycemic index.”

In other words, both fiber intake and a low-glycemic diet will decrease risk of metabolic syndrome, which is commonly characterized by increased weight circumference and abdominal fat, increased blood pressure and blood sugar, and more.

This bears great importance not just for diabetes, heart attack, and stroke prevention, but also for keeping the belly fat off.

Cardiovascular Event Risk

It’s not the only commonality linking obesity, diabetes, and heart disease, but high-glycemic eating is definitely among the primary suspects.

Another rather large systematic review by the Peking Union Medical College in Beijing found that both glycemic index and glycemic load increased risk for coronary heart disease and stroke.

Here’s a quick snapshot of the key findings from this study:

  • High GI and GL increased risk of coronary heart disease, especially among women.
  • High GL and average GI was positively correlated with stroke incidence.
  • Overweight subjects felt all of these effects more profoundly.


If we may switch teams for a moment, there are actually a few instances in which a rapid rise in blood sugar may be helpful, like in the case of hypoglycemia.

Hypoglycemia—low blood sugar—is a fairly common occurrence among medicated diabetics, but it can also affect people with liver or kidney disorders, eating disorders, pregnant women, or anyone who simply goes without eating for too long.

Whether you’re a visitor or a semi-permanent resident here, you don’t necessarily get a pass to binge on unhealthy foods.

Think apples, sweet potatoes, and bananas, not chips or bagels. 

For someone who experiences hypoglycemia on a regular basis, it’s always better to address the underlying cause of the issue with a doctor instead of relying on these pick-me-ups, because we’ve just seen what long-term consumption of high-GI/GL foods can do.


Finally, exercise-induced hypoglycemia can really throw a wrench in your progress and recovery.

If you consume enough carbs before a workout and avoid overtraining, it’s reasonably easy to avoid, but without these precautions, you may find yourself feeling dizzy, irritated, and (disproportionately) fatigued after a workout.

As before, it’s better to head off the crash before it can happen, but if you find yourself already in this situation, grab some moderately carb-dense fruit, vegetables, or whole wheat bread.

Key Takeaways

It’s good, it’s bad, it’s linked to diabetes, it’s not linked to diabetes, what’s the deal with low-glycemic eating?

Just like fat, carbs aren’t the enemy—it’s all about approaching them in the right way.

We rarely enjoy the luxury of straightforward answers when it comes to nutritional science, so it takes a little bit of patience and plenty of incisive questioning to arrive at the best possible guess.

When it comes to how the glycemic index and glycemic load affect overall health, these takeaways are the products of that effort:

  • While foods with low GI/GL are likely better for reducing diabetes and heart disease incidence, some high-GI/GL foods can be useful in certain scenarios (hypoglycemia, post-workout, etc.)
  • Low-GI/GL foods are usually healthier, but not always; carbohydrate content is not the only factor affecting nutritional value..
  • It’s okay to cross over the 50-point line once in a while, especially when the food is accompanied by fiber-rich and/or fatty foods.

Just like fat, carbs aren’t the enemy—it’s all about approaching them in the right way.

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