Sugar is NOT bad for you because it raises your blood sugar.
Sugar is bad for you because it causes dysbiosis in your gut => increases endotoxin => inflammation/metabolic dysfunction.
From the outset, it’s important to point out that “naked sugar” (think table sugar = sucrose and high fructose corn syrup) has different effects in the body than sugar consumed as part of fruits, fruit juice, honey, etc. We’ll get to this eventually…
Blood Sugar ≠ The Problem
Though glycemic variability may indicate underlying metabolic dysfunction, it’s the metabolic dysfunction that’s the issue, not the increase in blood glucose per se.
This is a very important point.
The idea that metabolic dysfunction (aka insulin resistance) arises from raising your blood sugar is also not supported by medical research.
Insulin-induced insulin resistance simply does not happen to any meaningful extent in humans (outside of insulin-producing tumors like an insulinoma or administration of IV insulin), and it certainly is NOT the cause of our current diabetes epidemic.
Evidence from Free-Living Populations
There are many examples of free-living humans who make the majority of their calories from carbohydrates. No free-living population of humans (i.e., not eating ultra-processed foods) shows evidence of insulin resistance.
- Consider the Tukisenta of New Guinea, who eat a diet of 90% carbohydrates and remain lean, fit, and metabolically healthy (PMID: 4718949).
- Or the Mbuti hunter-gatherers of the Congo, who treasure honey and eat it as the majority of their calories in the rainy season but remain metabolically healthy year-round (PMID: 24746602, 5009122).
Thus, there are many examples of humans eating “sugar” and/or raising their blood sugar frequently that do not result in metabolic dysfunction or insulin resistance.
Blood Sugar in Diabetes: Symptom, Not Cause
Though blood sugar is elevated in diabetes, this is a symptom and not a cause. Full stop.
If you disagree with this, please show me evidence that raising your blood sugar independent of metabolic dysfunction/insulin resistance is harmful to humans…
I didn’t think so.
Why “Naked Sugar” is Harmful
Now that we have that out of the way, let’s get to why “naked sugar” (sucrose, HFCS) is harmful.
There is ample evidence that “naked sugar,” aka processed sugar, leads to increased endotoxin—also known as LPS (a component of the gram-negative bacterial cell wall)—in the body.
There is also clear evidence that higher levels of endotoxin in human serum correlate with insulin resistance, metabolic dysfunction, inflammation, and obesity (PMID: 21636801).
Administering endotoxin to humans intravenously also leads to insulin resistance and inflammation of adipose tissue (PMID: 19794059).
The Role of Honey, Fruit, and Fruit Juice
Conversely, giving humans or animals sucrose-containing foods like honey, fruit, or fruit juice does not increase levels of endotoxin, lead to insulin resistance, or inflammation.
In one study, two different types of honey were shown to REVERSE inflammation caused by sucrose and HFCS in rats by affecting the gut microbiome, thus decreasing levels of endotoxin (PMID: 34980392).
This is likely because honey contains many compounds that prevent the dysbiosis induced by “naked sugars.”
Honey Improves Glucose Tolerance
While we’re talking about honey, I must also point to a study in humans showing that administration of honey IMPROVED metrics of glucose tolerance over an 8-week period (PMID: 19817641).
This stands in stark contrast to sugar/HFCS, which are known to worsen these metrics in humans.
The Big Picture
So, there’s pretty clear evidence that:
- “Naked sugars” like sucrose and HFCS cause dysbiosis, leading to increased levels of endotoxin => inflammation, insulin resistance, etc. (probably mostly through TLR4).
- Foods containing sugar like honey, fruit, and fruit juice actually do the opposite—most likely because of the hundreds of compounds they contain that prevent overgrowth of harmful bacteria in the gut, mitigating increases in endotoxin.
There’s also historical data of free-living humans (hunter-gatherer types) who eat LOTS of honey/fruit or carbohydrates in general (certainly “spiking” their blood sugar) and do NOT develop evidence of insulin resistance, obesity, etc.
It’s almost as if eating foods that occur in nature is good for us (how simple and elegant?), while eating foods that have been overly modified/processed leads to disease.
A Note for Diabetics
With this thread, I am NOT saying that diabetics should not be intentional about consuming honey or fruit/fruit juice.
I AM saying that honey, fruit, and fruit juice did NOT make someone diabetic, but “naked sugars” like sucrose and HFCS certainly could.
This is a VERY important distinction, and I think the mechanisms underlying why “naked sugars” cause insulin resistance and honey/fruit do not are fascinating.
- If you have diabetes, you MUST get rid of “naked sugar.”
- If you have diabetes, it’s also reasonable not to overconsume honey/fruit, but some moderate amount of these could actually be helpful at the level of your gut microbiome.
Final Thoughts
If you take nothing else away from this, I hope this thread will serve as a discussion starting point pushing back against the notion that anything that raises your blood sugar is harmful for you. That position is oversimplified and not supported by the literature.
Now go eat an orange or try a teaspoon of honey from a local farm. You’re welcome.