When Carbs, Proteins, & Fats Switch Metabolic Roles

Strange Things Happening In The Islets Of Langerhans

It is generally known and widely accepted that carbs have the biggest effect on blood sugar levels (and thus insulin response), fats less so, and protein least of all.

And yet, there was a groundbreaking study published yesterday which found:

❝Glucose is the well-known driver of insulin, but we were surprised to see such high variability, with some individuals showing a strong response to proteins, and others to fats, which had never been characterized before.

Insulin plays a major role in human health, in everything from diabetes, where it is too low*, to obesity, weight gain and even some forms of cancer, where it is too high.

These findings lay the groundwork for personalized nutrition that could transform how we treat and manage a range of conditions.❞

~ Dr. James Johnson

*saying ”too low” here is potentially misleading without clarification; yes, Type 1 Diabetics will have too little [endogenous] insulin (because the pancreas is at war with itself and thus isn’t producing useful quantities of insulin, if any). Type 2, however, is more a case of acquired insulin insensitivity, because of having too much at once too often, thus the body stops listening to it, “boy who cried wolf”-style, and the pancreas also starts to get fatigued from producing so much insulin that’s often getting ignored, and does eventually produce less and less while needing more and more insulin to get the same response, so it can be legitimately said “there’s not enough”, but that’s more of a subjective outcome than an objective cause.

Back to the study itself, though…

What they found, and how they found it

Researchers took pancreatic islets from 140 heterogenous donors (varied in age and sex; ostensibly mostly non-diabetic donors, but they acknowledge type 2 diabetes could potentially have gone undiagnosed in some donors*) and tested cell cultures from each with various carbs, proteins, and fats.

They found the expected results in most of the cases, but around 9% responded more strongly to the fats than the carbs (even more strongly than to glucose specifically), and even more surprisingly 8% responded more strongly to the proteins.

*there were also some known type 2 diabetics amongst the donors; as expected, those had a poor insulin response to glucose, but their insulin response to proteins and fats were largely unaffected.

What this means

While this is, in essence, a pilot study (the researchers called for larger and more varied studies, as well as in vivo human studies), the implications so far are important:

It appears that, for a minority of people, a lot of (generally considered very good) antidiabetic advice may not be working in the way previously understood. They’re going to (for example) put fat on their carbs to reduce the blood sugar spike, which will technically still work, but the insulin response is going to be briefly spiked anyway, because of the fats, which very insulin response is what will lower the blood sugars.

In practical terms, there’s not a lot we can do about this at home just yet—even continuous glucose monitors won’t tell us precisely, because they’re monitoring glucose, not the insulin response. We could probably measure everything and do some math and work out what our insulin response has been like based on the pace of change in blood sugar levels (which won’t decrease without insulin to allow such), but even that is at best grounds for a hypothesis for now.

Hopefully, more publicly-available tests will be developed soon, enabling us all to know our “insulin response type” per the proteome predictors discovered in this study, rather than having to just blindly bet on it being “normal”.

Ironically, this very response may have hidden itself for a while—if taking fats raised insulin response without raising blood sugar levels, then if blood sugar levels are the only thing being measured, all we’ll see is “took fats at dinner; blood sugars returned to normal more quickly than when taking carbs without fats”.

You can read the study in full here:

Proteomic predictors of individualized nutrient-specific insulin secretion in health and disease

Want to know more about blood sugar management?

You might like to catch up on:

• 10 Ways To Balance Your Blood Sugars
• Track Your Blood Sugars For Better Personalized Health
• How To Turn Back The Clock On Insulin Resistance

Take care!