The Hidden Link Between Food Form and Blood Sugar

This Week’s Research Highlight

Sometimes, nutrition labels don’t tell the full story.

Take almonds, for instance. They are supposed to deliver about 170 calories per serving. But as it turns out, that number really depends on how you eat them.

In one study, researchers gave participants equal portions of almonds — same weight, same ingredients, same macronutrients. The only difference was their physical form: whole, chopped, roasted, or ground into almond butter.

Almond butter yielded nearly 100% of the predicted calories. Whole almonds, on the other hand, came up about 25% short of what would be expected.

You see, food processing doesn’t merely change texture or shelf life. It can alter how much energy we extract, how nutrients are absorbed, and how our bodies respond.

This insight is reshaping how scientists think about nutrition, causing them to examine not just the chemical composition of the foods we eat, but how they are built.

A new study takes this principle deeper — all the way into the digestive tract — to show how subtle differences in the physical structure of a single food can reprogram digestion, metabolism, and appetite from the inside out.

The Experimental Design

To isolate the effects of food structure on digestion and metabolism, researchers designed an experiment that was both remarkably precise and unusually invasive. Everything else was held constant — calories, macros, fiber, even flavoring — while just one thing changed: the microstructure of the food.

Each meal was made from chickpeas, cooked into a porridge and lightly sweetened with fruit jelly. But internally, they were worlds apart.

• In the Broken version, chickpeas were puréed before cooking, rupturing nearly every cell.
• In the Intact-S version, chickpeas were cooked first, then gently processed to separate the cells without breaking them — resulting in a slurry of isolated but intact cells.
• The Intact-C version skipped that second step, preserving clusters of intact cells, closer to the original tissue structure.

However, the researchers didn’t stop there. Here is where we get to the invasive part of the study.

To find out what happened after the food was eaten, they went straight to the source — by threading flexible catheters through each participant’s nose, down the throat, and into the stomach and small intestine.

It’s the kind of protocol that tends to weed out the faint of heart. And yet, ten healthy adults signed up for this. The participants lived in a clinical research unit for four days, ate all three versions of the meal in randomized order, and allowed researchers to sample their digestive contents every 15 to 30 minutes.

In this way, the researchers could track, moment by moment, how the structure of a meal shaped its breakdown in the stomach, its chemical fingerprint in the small intestine, as well as the hormonal responses it elicited in the blood.

Same Calories, Different Glucose

Each meal delivered 30 grams of starch and the same amount of fiber. On paper, they should have produced identical blood sugar responses.

But the body didn’t see it that way.

After the broken meal — where every chickpea cell was ruptured — blood glucose surged. The separated-cell meal blunted that spike somewhat. But it was the clustered intact version that kept glucose levels lowest.

And the difference wasn’t subtle.

Compared to the clustered intact meal, the broken meal produced a 190% higher glucose peak, and a 148% larger total blood sugar exposure over the following hours (measured by incremental area under the curve, or iAUC).

Insulin followed suit: the broken meal triggered a 74% greater insulin response, and it stayed elevated longer. After the clustered intact meal, insulin returned to baseline over an hour earlier, a sign that the body needed less effort to regulate blood sugar.

Blood glucose response to meals with different structures.

(a) Blood glucose levels over time. The broken meal caused a sharper and higher spike than either intact version.

(c) Total glucose exposure (iAUC). Participants absorbed significantly more glucose from the broken meal compared to the clustered intact version, despite identical starch content.

Insulin response to meals with different structures.

(d) Blood insulin levels over time. After the broken meal, insulin rose higher and stayed elevated longer.

(f) Total insulin exposure (iAUC). Insulin levels were greatest for the broken meal, and lowest for the clustered intact meal.

Gut Hormones: Slower Digestion, Stronger Signals

Blood sugar wasn’t the only thing that changed. The structure of the meal rewired how the gut talked back.

When food moves through the digestive tract, specialized cells in the gut wall monitor the chemical composition of what’s passing by, and release hormones in response. Two of the most important are GLP-1 and PYY.

Both hormones play key roles in regulating appetite, blood sugar, and insulin. GLP-1 helps stimulate insulin release, slows gastric emptying, and promotes satiety. PYY acts as a brake on appetite, telling the brain (and the stomach) that the meal is over. Together, they help calibrate how much we eat and how we metabolize what we’ve eaten.

After the Broken meal, GLP-1 spiked early and faded fast. In contrast, both intact versions produced a more gradual and sustained GLP-1 response, with 63% greater hormone levels in the later postprandial period.

PYY told a similar story. While the broken meal barely moved the needle, the separated intact meal triggered a substantial increase — 214% higher PYY levels compared to the broken condition. The Clustered meal showed a similar (though slightly smaller) effect.

Importantly, appetite ratings tracked with these hormonal patterns. Participants felt fuller and more satisfied after the intact meals, despite having consumed the same calories.

GLP-1 response to meals with different structures

(d) After the broken meal, GLP-1 peaked early and declined quickly.

(f) Total GLP-1 exposure (iAUC) over three hours was significantly higher after the separated-cell meal.

PYY response to meals with different structures

(g) The broken meal barely moved PYY levels. But after the separated-cell meal, PYY rose gradually and stayed elevated — a delayed signal of satiety.

(i) Total PYY exposure (iAUC) was over twice as high with the separated-cell meal compared to the broken one.

Microscopic Changes, Macroscopic Impact

To understand what was going on, researchers looked directly inside the gut. They collected fluid from the stomach and small intestine and examined it under the microscope.

The images tell the story.

Microscope images of stomach (left column) and small intestine (right column) contents.

The Broken meal (b, c) was reduced to digested debris — no intact cells remained.

The Intact-S meal (e, f) preserved single cells, still visibly intact in the gut.

The Intact-C meal (h, i) retained large clusters of sealed cells, resisting breakdown.

After the broken meal, no chickpea cells remained — just a slurry of digested starch and plant debris. But in the intact meals, cellular structure persisted for hours. Whole cells, even visible clusters, were still intact three full hours after ingestion, having survived chewing, acid, and enzymes.

The difference came down to encapsulation.

Plant cells are tiny nutrient capsules, each surrounded by a rigid wall of fiber. Inside are starches, fats, and proteins. Unless those walls are breached, digestive enzymes can’t get in.

In the broken meal, every capsule had already burst — like a tray of open lunchboxes, spilling their contents the moment they hit the gut. In the intact meals, those walls were still sealed, keeping nutrients physically locked away and digestion delayed.

And that structural resilience had metabolic consequences.

The broken meal flooded the stomach with digestible sugars, already broken down and ready for absorption. The intact meals, by contrast, released up to 80% less starch into the stomach early on and left over 40% more undigested starch in the small intestine.

That slowed delivery shifted where nutrients were sensed. Instead of overwhelming the upper gut, the intact meals sent more starch downstream, triggering a stronger, delayed release of GLP-1 and PYY.

Perhaps most revealing, the separated-cell meal had the same protective effect. Just keeping the cell walls sealed was enough to rewrite the metabolic script.

And the implications of that, needless to say, extend far beyond chickpeas.

Why Food Form Matters

This is really a story of how food structure shapes metabolism, and how modern processing dismantles it.

When we blend, mill, mash, or extrude plant-based ingredients, we shatter the microscopic scaffolding that slows digestion and modulates hormonal responses. What would naturally be a slow trickle turns into a flood. Blood sugar spikes. Hunger comes roaring back sooner.

Indeed, this is a fundamental hallmark of ultra-processed foods.

In a landmark inpatient study, people ate over 500 extra calories per day on an ultra-processed diet compared to a minimally processed one — even though the meals were carefully matched for calories, sugar, fat, fiber, and protein. What made the difference? Texture and speed. The ultra-processed meals were softer, easier to chew, and went down significantly faster.

That’s why “macro-matched” products — bars, pastas, protein snacks —have been shown to behave differently in the body, even when the label reads like a wellness manifesto. A bowl of steel-cut oats doesn’t hit like oat flour pancakes. Chickpea puffs vanish by the handful. Almond butter is basically pre-chewed.

None of this means processed foods are off-limits. But it does mean structure matters — and you won’t ever see that on a nutrition label.

Some general rules of thumb:

• Favor foods that preserve their cellular integrity: whole beans, intact grains, whole fruit.
• Watch the texture. If it chews like baby food, it probably digests like it too.
• Be skeptical of snacks made from “whole food” ingredients that show up as crisps, cookies, or bars.

Summary: In a randomized crossover trial, ten healthy adults consumed three nutritionally identical chickpea-based meals that varied only in cellular structure: (1) a puréed meal with fully ruptured cells ("Broken"), (2) a meal composed of separated but intact single cells ("Intact-S"), and (3) a meal containing clusters of intact cells ("Intact-C"). Participants lived in a metabolic research facility and underwent repeated blood sampling as well as direct gastric and duodenal aspirates via nasoenteric tubes. Despite identical macronutrient and fiber content, the meals produced markedly different physiological responses. The Broken meal elicited significantly higher postprandial blood glucose and insulin levels — 190% and 74% greater, respectively — compared to the Intact-C meal. Hormonal responses also diverged: the Intact-S meal led to a 63% greater GLP-1 response and 214% higher PYY release compared to the Broken meal. Microscopy and metabolite analyses confirmed that intact cell structures slowed starch digestion and shifted nutrient sensing to the distal small intestine. The findings demonstrate that cellular architecture alone, independent of nutrient composition, can meaningfully alter postprandial glycemic and hormonal responses.

Random Trivia & Weird News

🛻 A GPS-tracked seagull was caught hitchhiking on a garbage truck — twice.

Why fly inland when there’s an 18-wheeler heading your way?

Western gulls from the Farallon Islands often forage in San Francisco. But one clever bird rode in the back of a truck 80 miles to a compost site near Modesto.

After a snack, she flew back to the coast.

It’s the first documented case of a gull using human transportation to find food…and maybe not the last. As climate change depletes ocean prey, seabirds are adapting in ways that are remarkably resourceful (and a little ridiculous).

Not your average commute: This gull hitched a ride in a garbage truck from San Francisco to Modesto (blue), then flew back the next day (red). Avian logistics at their finest.

Podcasts We Loved This Week

• Siim Land: Longevity supplements — NR, NMN, astaxanthin, AKG, glycine, GlyNAC, & ergothioneine. Via Reason & Wellbeing.

• Paul Tough: What Americans get wrong about ADHD. Via Plain English with Derek Thompson.

Products We Like

SOMOS Mexican Black Beans

Unlike canned beans that break down into mush, these beans hold their shape — meaning slower digestion, better satiety, and a milder blood sugar curve.

Bonus: they’re also convenient (90 seconds in the microwave) and pack 15g fiber, 20g protein, and 1390mg potassium per pouch.

I always keep a stash in the pantry for those days when I want real food but can’t be trusted with a knife.

humanOS Catalog Feature of the Week

The Mediterranean Diet Course

The Mediterranean Diet is more than a heart-healthy pattern. It’s a microbiome-supporting, inflammation-lowering, cell-rejuvenating way of eating.

In this course, you’ll learn how this dietary pattern:

• Feeds beneficial gut microbes and promotes anti-inflammatory metabolites
• Boosts memory and helps defend against cognitive decline
• Improves stress resilience and exercise performance — in as little as 4 days
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Plus, we unpack the real science behind olive oil, fiber, polyphenols, as well as a little-known molecule called spermidine — and show you how to Mediterranean-ize any style of cooking.

To Access:

1. Log in to humanOS.
2. See Mini-Courses in navigation on the left-hand side
3. Click Mediterranean Diet

Wishing you the best,