● Food Intelligence · Vegetable

Kale Glycemic Index and Calculate Your Own Glucose Response

Across 24,753 kale logs from 6,392 Signos members, meals averaged +29.1 mg/dL — but kale itself (GI 15, GL 1) carries almost no glycemic load. The cohort signal comes from what's around the leaves: a kale-Caesar with croutons holds at +28 mg/dL, while a kale grain bowl pushes to +35.4 mg/dL — a +8 mg/dL delta driven by the rice or quinoa, not the kale.

GS
Reviewed by Grace Shryack
Signos Proprietary Data·Updated May 02, 2026·10 min read

● Powered by Signos cohort dataHigh confidence · n=24,753
The swap calculator below draws on 24,753 matched-pair logs — a broader cohort than the page's single-item primary, used to give every ingredient swap statistical power. Welch's t-test on matched pairs, not third-party glycemic-index tables. Each swap shows its sample size and confidence tier inline.
● FREE SIGNOS TOOL

Build Your Own Low GI Recipe

Powered by 24,753
Signos food logs

Tap any ingredient below to swap it for a glucose-friendlier alternative. Your Signos Glucose Score, predicted curve, and nutrition update in real-time. Every swap is data-backed by real CGM response measurements.

Ingredients — Tap to Swap
Meal Context
Pre-meal sequence
Activity after meal
Time of day
39
of 100
Signos Glucose Score
Moderate Spike Risk
75% of members fall between +24 and +34 mg/dL
Predicted Curve · 3-hr window
1401001201401601800m30m60m90m120m150m180m+29
Peak
+29
mg/dL
Time in Range
100%
3hr window
Above 140
0m
danger zone
Swaps
0
applied
Want your real response?
Predictions are cohort averages. Wear a CGM to see your actual response.
Get a Signos CGM →
● Key Findings · Does kale spike blood sugar?

No — kale itself is glucose-flat (GI 15, GL 1). The +29.1 mg/dL cohort average comes from what's eaten alongside it: bread, croutons, smoothie sweeteners, and grain-bowl rice. Across 24,753 logged meals containing kale, the average glucose peak was +29.1 mg/dL (median +25 mg/dL). But kale's published glycemic load is just 1 — meaning the kale itself contributes almost nothing to that peak. The signal comes from context: a kale grain bowl averaged +35.4 mg/dL (+8 mg/dL above kale alone), a kale wrap averaged +34.7 mg/dL (+7 mg/dL), while a kale Caesar with croutons held at +28.0 mg/dL — statistically indistinguishable from kale alone. Light-carb meals with kale held at +25.7 mg/dL; very-heavy-carb meals (110g+) pushed to +42.5 mg/dL. The leaves are the constant; the carbs around them are the variable.

  • ▸Kale is glucose-flat by published reference: GI 15, GL 1 — among the lowest scores on the Harvard table. Single-item kale logs averaged just +29.4 mg/dL across 1,206 meals.
  • ▸The carb-load effect dwarfs every other modifier: meals with ≥60g carbs peaked at +42.5 mg/dL — 47.7% above the low-carb baseline of +25.7 mg/dL (n=3,934 vs n=15,789, p<0.001).
  • ▸Grain bowls add the biggest single carb penalty: kale in a grain bowl averages +35.4 mg/dL vs +27.5 mg/dL for kale alone — a +8 mg/dL jump across 2,063 logs driven by the rice or quinoa, not the kale.
  • ▸Morning timing lowers the spike: kale meals logged before 10 am averaged 18.2% lower peaks than the rest of the day (CI: −6.11 to −4.88 mg/dL, n=3,491, p<0.001).
● Signos Rules

Three citable insights from this recipe's data

Rule 1
"The Glucose-Flat Leaf"
GI 15 / GL 1
Kale's published glycemic index is 15 and its glycemic load is 1 — both at the floor of the Harvard table. In our cohort, single-item kale logs averaged just +29.4 mg/dL on ~306 kcal, with a median of +27 mg/dL. The cohort signal isn't kale; it's whatever else lands on the plate. Track your kale Caesar's peak and you're really tracking the croutons.
Rule 2
"The Grain-Bowl Penalty"
+8 mg/dL vs. kale alone
Adding kale to a grain bowl pushes the average peak from +27.5 to +35.4 mg/dL — the largest carb-pair delta we measured (n=2,063, confidence: high). The kale doesn't change; the rice or quinoa underneath does. Wraps add +7 mg/dL across 400 logs (medium confidence) for the same reason: the tortilla, not the leaves, drives the response.
Rule 3
"The Morning Edge"
−18% peak
Kale logged before 10 am averages 18% lower glucose peaks than the same food logged later in the day (n=3,491 morning logs vs. n=18,222 non-morning, p<0.001). Breakfast meals containing kale averaged +25.5 mg/dL — the lowest of any meal-time slot — compared to +30.0 mg/dL at lunch and +30.2 mg/dL at dinner. Earlier insulin sensitivity likely drives the gap.
● Curious about your own?

Curious how your body responds to kale specifically?

Across 24,753 logged kale meals, the average glucose peak was +29.1 mg/dL — but kale itself is GI 15, GL 1. The IQR spans 26 mg/dL (p25: +15, p75: +41), meaning individual responses vary enormously based on what's on the plate alongside the leaves. Your own result depends on meal context, carb pairing, and metabolic state. A CGM tells you which side of that range you actually land on.

Learn how Signos works
Why this meal spikes

This meal stacks 3 independent spike drivers — together they account for +28 mg/dL.

Driver 1
Meal-level carbohydrates (≥60g when paired)
+12 mg/dL
The dominant lever: meals with ≥60g carbs ran 47.7% higher than low-carb logs (p<0.001, n=3,934 vs n=15,789). Kale itself is GL 1, so this effect is entirely from what it's eaten with — grain-bowl rice, wrap tortillas, smoothie sweeteners.
Driver 2
Sugar content in pairings (≥20g)
+8 mg/dL
Meals with ≥20g of sugar ran 28.8% higher than the low-sugar baseline (CI: +7.03 to +8.47 mg/dL, n=3,439, p<0.001). For kale, this typically means the smoothie or green-juice sweetener — banana, mango, honey — not the leaves.
Driver 3
Individual glucose variability (IQR 26 mg/dL)
+6 mg/dL
The interquartile range spans 26 mg/dL (p25: +15, p75: +41 mg/dL), meaning personal metabolic state — insulin sensitivity, microbiome, stress — accounts for a substantial portion of any given reading.
● Which bucket are you in?

Some members spike +25.7 mg/dL. Others spike +42.5. The only way to know how you'll spike is to measure with a Signos CGM.

See Signos Plans
S
● What surprised us
What surprised us about kale is how clean the editorial story is once you separate the leaf from the meal. Kale's published GI is 15 and its GL is 1 — basically zero. But the cohort average came in at +29.1 mg/dL across 24,753 logs. The gap is entirely meal context. A kale-Caesar with croutons logs at +28.0 mg/dL — kale plus bread. A kale grain bowl logs at +35.4 mg/dL — kale plus rice. The kale isn't doing anything; everything else on the plate is.
— Signos Data Science Team

Why this happens, physiologically

Kale is a near-zero-carb leafy green — published GI 15, GL 1 — so its +29.1 mg/dL cohort average across 24,753 meals is driven almost entirely by what surrounds it on the plate. The single biggest lever measured is total meal carb load: meals with ≥60g of carbs ran 47.7% higher than the low-carb baseline (p<0.001, n=3,934), and the carb-bucket analysis shows a near-linear escalation from +25.7 mg/dL in light (0–40g carb) meals to +42.5 mg/dL in very-heavy (110g+) meals — a 65% jump. Two secondary levers pull in the opposite direction: protein pairings (≥15g) trimmed the response by ~12% (n=19,940, p<0.001) and morning timing (before 10 am) trimmed it by ~18% (n=3,491, p<0.001). The mechanism is observational, not yet causal, but the pattern is consistent with kale acting as a glucose-flat carrier — the leaves contribute almost nothing, and the response tracks the surrounding meal.

● Three mechanisms explain kale's glucose range

Meal carb load, protein co-ingestion, and time-of-day each drive measurable shifts in the kale-meal glucose response

  1. Mechanism 1
    +47.7%
    High carb co-load
    Meals logged with ≥60g total carbs showed peaks 47.7% above the low-carb baseline (n=3,934, p<0.001). Kale itself adds almost no digestible carbs — every point of that 47.7% comes from what it's eaten with: grain-bowl rice, wrap tortillas, smoothie sweeteners.
  2. Mechanism 2
    −12%
    Protein co-ingestion
    Protein pairings ≥15g cut the response by ~12% (n=19,940, p<0.001). Protein slows gastric emptying and blunts the glycemic excursion from any co-ingested carbs — useful when kale arrives in a grain bowl or wrap rather than alone.
  3. Mechanism 3
    −18%
    Morning timing
    Kale logged before 10 am averaged 18.2% lower peaks than the rest of the day (n=3,491, p<0.001). Earlier insulin sensitivity likely drives the gap; breakfast kale meals averaged +25.5 mg/dL versus +30.2 mg/dL at dinner.
● Fit Check
Kale is glucose-flat on its own — what surrounds it determines the spike.
✓ This is for you if
  • ▸You eat kale as a side salad or with eggs at breakfast. Single-item kale logs averaged +29.4 mg/dL with 35.9% of responses in the low range.
  • ▸You reach for kale chips as a snack. Kale chips averaged +22.3 mg/dL — 5.3 mg/dL below the fresh-salad baseline across 211 logs.
  • ▸You keep total meal carbs under 40g. Light-carb kale meals averaged just +25.7 mg/dL — the lowest carb bucket in the cohort.
  • ▸You time kale toward the morning. Kale meals before 10 am averaged 18% lower peaks than later-day logs across 3,491 meals.
✗ Not for you if
  • ▸You build kale into a grain bowl with rice or quinoa. That pairing adds +8 mg/dL over kale alone across 2,063 matched logs — the largest carb-pair penalty measured.
  • ▸You blend kale into a smoothie with banana, mango, or honey. Smoothie sweeteners pushed the high-sugar bucket 28.8% above the low-sugar baseline across 3,439 logs.
  • ▸You wrap kale in a tortilla. Kale wraps averaged +34.7 mg/dL — a +7 mg/dL delta over kale alone across 400 logs.
  • ▸You stack kale on a 110g+ carb meal. Very-heavy-carb meals averaged +42.5 mg/dL — 65% above the light-carb baseline of +25.7 mg/dL.
● How it fits your day

Calorie band and pairings (member-measured)

Per serving
30–500 kcal
Ranges from a small kale side salad (~30 kcal) to a kale-topped grain bowl (~500 kcal); single-item logs averaged 306 kcal.
● Pair before
  • ▸Pair kale with a protein source: high-protein pairings (≥15g) cut the response by ~12% across 19,940 logs (p<0.001).
  • ▸Keep total meal carbs under 40g: light-carb kale meals averaged +25.7 mg/dL vs. +42.5 mg/dL in the 110g+ bucket — a 65% escalation.
● Pair after
  • ▸Time a 15–20 min walk after grain-bowl kale meals, which averaged +35.4 mg/dL — the highest pairing spike in the cohort.
  • ▸If dinner is kale-heavy, note that breakfast kale logs averaged +25.5 mg/dL vs +30.2 mg/dL at dinner — favor morning timing when possible.
● Avoid pairing
  • ▸Avoid kale grain bowls with white rice: that pairing added +8 mg/dL over kale alone (treatment mean +35.4 mg/dL, n=2,063).
  • ▸Avoid blending kale with high-sugar fruit. The high-sugar bucket (≥20g) ran 28.8% above the low-sugar baseline (CI: +7.03 to +8.47 mg/dL, n=3,439).
● Quick definitions (click to expand)
mg/dL — milligrams per deciliter. The unit blood glucose is measured in. A rise of "+30 mg/dL above baseline" means blood sugar went up 30 units after the meal.
Glycemic Index (GI) — a 0–100 score for how fast a food raises blood sugar in lab tests. Under 55 = low, 56–69 = medium, 70+ = high.
Glycemic Load (GL) — GI adjusted for portion size. Under 10 = low, 10–19 = medium, 20+ = high.
CGM — Continuous Glucose Monitor. A wearable sensor that tracks blood glucose every few minutes. Signos members wear CGMs while eating meals they log.
● Related Foods: How kale's glucose response compares to other leafy greens and vegetables
Spinach Glycemic Index & Glucose Score
Spinach is the closest analog — another GL-1 leafy green. Compare how their cohort signals diverge based on what each is paired with.
Lettuce Glycemic Index & Glucose Score
Lettuce shares kale's glucose-flat profile. See how its cohort behaves across salads, wraps, and bowls.
Broccoli Glycemic Index & Glucose Score
Broccoli is the cruciferous neighbor. Its slightly higher fiber load shifts how it pairs with grain bowls and pasta.
Cabbage Glycemic Index & Glucose Score
Cabbage rounds out the leafy-cruciferous set — see how slaws and stir-fries compare to kale's salad and grain-bowl signals.
Cauliflower Glycemic Index & Glucose Score
Cauliflower replaces grain in many bowls — the comparison shows what kale-on-cauli-rice would look like vs. kale-on-rice.
Track Your Kale Response with Signos →
See how your glucose reacts to kale alone vs. in a grain bowl, smoothie, or wrap — CGM data, personalized to you.

Frequently Asked Questions

Methodology

This page draws on 24,753 kale logs from 6,392 unique Signos members, including 1,206 single-item kale logs (meals where kale was logged alone, no pairings), collected through the Signos production CGM platform. Data were filtered to postprandial glucose responses (PPGR) between 0 and 100 mg/dL to exclude sensor artifacts and implausible readings. Modifier effects were estimated using Welch's t-test on matched pairs against a defined baseline; all reported effects carry p<0.001 unless noted. We report mean glucose peak across a right-skewed distribution — the median single-item spike of +27 mg/dL is a few mg/dL lower than the mean of +29.4 mg/dL, which is typical for this type of data. The food was identified in member logs using a regex that matched "kale" as a primary ingredient. Any carb-pair sub-cohort requires at least 100 matched meals before it appears in the recipe builder.

Limitations

  • Self-reported portion sizes introduce measurement error — a logged "kale salad" may vary significantly in actual leaf weight, dressing volume, and crouton count, affecting per-serving spike estimates.
  • Cohort skews health-motivated; Signos members actively tracking glucose tend to eat more mindfully than the general population, so real-world average kale-meal spikes may differ.
  • The lacinato/dinosaur kale sub-cohort is small (n=43) and carries low confidence — its reported delta of −0.6 mg/dL vs. fresh kale should be treated as directional only, not statistically firm.
  • The kale chips sub-cohort has medium confidence (n=211); treat its −5.3 mg/dL delta as a directional estimate pending a larger sample.
  • Sautéed/massaged kale and curly kale sub-cohorts had insufficient sample (n=1 and n=0 respectively) and are excluded from the recipe builder.
  • Modifier analyses reflect meal-level correlations, not controlled feeding trials — causality cannot be established from observational CGM data alone.
  • The cohort signal of +29.1 mg/dL diverges from kale's published GI of 15 / GL of 1 because members rarely eat kale alone — meal-level co-ingestion (croutons, rice, smoothie sweetener) explains the gap.
● Get your own data

See your own kale response

Across 24,753 logged kale meals, the cohort averaged +29.1 mg/dL — but kale itself is glucose-flat. What's on the plate matters more: a grain bowl adds +8 mg/dL, a wrap adds +7 mg/dL, while kale alone holds at +27.5 mg/dL. A CGM shows you exactly where you land and which kale builds work best for your biology.

Start with Signos
50,000+
Members Measuring