Glycemic Index vs Glycemic Load vs Insulin Index

How To Actually Use Those Indices

Carbohydrates are essential for our life, and/but often bring about our early demise. It would be a very conveniently simple world if it were simply a matter of “enjoy in moderation”, but the truth is, it’s not that simple.

To take an extreme example, for the sake of clearest illustration: The person who eats an 80% whole fruit diet (and makes up the necessary protein and fats etc in the other 20%) will probably be healthier than the person who eats a “standard American diet”, despite not practising moderation in their fruit-eating activities. The “standard American diet” has many faults, and one of those faults is how it promotes sporadic insulin spikes leading to metabolic disease.

If your breakfast is a glass of orange juice, this is a supremely “moderate” consumption, but an insulin spike is an insulin spike.

Quick sidenote: if you’re wondering why eating immoderate amounts of fruit is unlikely to cause such spikes, but a single glass of orange juice is, check out:

Which Sugars Are Healthier, And Which Are Just The Same?

Glycemic Index

The first tool in our toolbox here is glycemic index, or GI.

GI measures how much a carb-containing food raises blood glucose levels, also called blood sugar levels, but it’s just glucose that’s actually measured, bearing in mind that more complex carbs will generally get broken down to glucose.

Pure glucose has a GI of 100, and other foods are ranked from 0 to 100 based on how they compare.

Sometimes, what we do to foods changes its GI.

• Some is because it changed form, like the above example of whole fruit (low GI) vs fruit juice (high GI).
• Some is because of more “industrial” refinement processes, such as whole grain wheat (medium GI) vs white flour and white flour products (high GI)
• Some is because of other changes, like starches that were allowed to cool before being reheated (or eaten cold).

Broadly speaking, a daily average GI of 45 is considered great.

But that’s not the whole story…

Glycemic Load

Glycemic Load, or GL, takes the GI and says “ok, but how much of it was there?”, because this is often relevant information.

Refined sugar may have a high GI, but half a teaspoon of sugar in your coffee isn’t going to move your blood sugar levels as much as a glass of Coke, say—the latter simply has more sugar in, and just the same zero fiber.

GL is calculated by (grams of carbs / 100) x GI, by the way.

But it still misses some important things, so now let’s look at…

Insulin Index

Insulin Index, which does not get an abbreviation (probably because of the potentially confusing appearance of “II”), measures the rise in insulin levels, regardless of glucose levels.

This is important, because a lot of insulin response is independent of blood glucose:

• Some is because of other sugars, some some is in response to fats, and yes, even proteins.
• Some is a function of metabolic base rate.
• Some is a stress response.
• Some remains a mystery!

Another reason it’s important is that insulin drives weight gain and metabolic disorders far more than glucose.

Note: the indices of foods are calculated based on average non-diabetic response. If for example you have Type 1 Diabetes, then when you take a certain food, your rise in insulin is going to be whatever insulin you then take, because your body’s insulin response is disrupted by being too busy fighting a civil war in your pancreas.

If your diabetes is type 2, or you are prediabetic, then a lot of different things could happen depending on the stage and state of your diabetes, but the insulin index is still a very good thing to be aware of, because you want to resensitize your body to insulin, which means (barring any urgent actions for immediate management of hyper- or hypoglycemia, obviously) you want to eat foods with a low insulin index where possible.

Great! What foods have a low insulin index?

Many factors affect insulin index, but to speak in general terms:

• Whole plant foods are usually top-tier options
• Lean and/or white meats generally have lower insulin index than red and/or fatty ones
• Unprocessed is generally lower than processed
• The more solid a food is, generally the lower its insulin index compared to a less solid version of the same food (e.g. baked potatoes vs mashed potatoes; cheese vs milk, etc)

But do remember the non-food factors too! This means where possible:

• reducing/managing stress
• getting frequent exercise
• getting good sleep
• practising intermittent fasting

See for example (we promise you it’s relevant):

Fix Chronic Fatigue & Regain Your Energy, By Science

…as are (especially recommendable!) the two links we drop at the bottom of that page; do check them out if you can

Take care!