04/29/2026
There’s a lot of buzz right now around a genetic study suggesting that what your blood sugar does after you eat may be a stronger signal for future brain health than fasting glucose.
That’s directionally important. I have educated for years that it is the postmeal blood sugar that is the earlier signal of glucose dysregulation versus fasting glucose.
In fact it is insulin resistance that is behind glucose dysregulation in the first place, and we can measure fasting insulin, an even earlier marker, before post meal spikes become manifest (I discussed this in a video I posted yesterday if you want to scroll down).
Nevertheless, work using approaches like Mendelian randomization adds weight to the idea that repeated post-meal glucose spikes may play a causal role in long-term metabolic risks, including neurodegeneration.
But interpretation matters.
Carbohydrates sources are not a monolith. The metabolic response to food depends on structure, fiber, protein pairing, and overall pattern.
Conflating refined, rapidly absorbed sources with intact, fiber-rich foods risks conclusions that don’t align with outcome data consistently showing benefit from foods like whole fruit, legumes and whole grains, for instance.
Equally important, glucose exposure is not just about what you eat. It’s also about what you do or don’t do after you eat. Even brief post-meal movement can meaningfully blunt glucose excursions.
For those who track their numbers, a practical, conservative guide is to keep most 1-hour post-meal values around or below ~140 mg/dL, recognizing this is not a hard cutoff. Risk signals tend to become more consistent as values move into the mid-150s and above (as seen in Oral Glucose Tolerance Test data), but the bigger issue is the pattern of repeated spikes over time.
And just as important, this isn’t a call for extremism. Health is built on patterns, not perfection. Dose and frequency matter. There’s room to enjoy life, including less-than-ideal foods, within a rational, balanced approach.
The takeaway is not “avoid carbohydrates.”
It’s to reduce refined, rapidly absorbed sources, keep high-fiber whole foods in the mix, move after meals, and avoid the trap of all-or-nothing thinking.
Study summary: https://www.sciencedaily.com/releases/2026/01/260115022756.htm