● Food Intelligence · Vegetable

Broccoli Glycemic Index and Calculate Your Own Glucose Response

Across 78,005 logged broccoli meals, members averaged +29.4 mg/dL — but the cohort number masks a clear split: broccoli alone (or with cheese sauce) holds at +27–28 mg/dL, while rice on the side pushes the same plate to +39.5 mg/dL and very-heavy-carb meals climb to +45.1 mg/dL, a 79% escalation driven almost entirely by the starch beside the florets.

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

● Powered by Signos cohort dataHigh confidence · n=78,005
The swap calculator below draws on 78,005 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.
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Meal Context
Pre-meal sequence
Activity after meal
Time of day
38
of 100
Signos Glucose Score
Moderate Spike Risk
75% of members fall between +23 and +33 mg/dL
Predicted Curve · 3-hr window
1401001201401601800m30m60m90m120m150m180m+28
Peak
+28
mg/dL
Time in Range
100%
3hr window
Above 140
0m
danger zone
Swaps
0
applied
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● Key Findings · Does broccoli spike blood sugar?

Barely on its own — broccoli alone averaged +27 mg/dL across 26,418 logs, but the meal as a whole averaged +29.4 mg/dL because of what was beside it. Across 78,005 logged broccoli meals, the average glucose peak was +29.4 mg/dL (median +25 mg/dL). With a published GI of 15 and GL of 1, broccoli is one of the lowest-glycemic vegetables in the Harvard table. In our cohort, the lever isn't the florets — it's the starch beside them: pairing broccoli with rice pushes the average peak from +27.0 to +39.5 mg/dL (+12 mg/dL across 7,541 logs), and very-heavy-carb meals (110g+) climb to +45.1 mg/dL. Cheese pairings, by contrast, add just +1 mg/dL — broccoli with cheese is essentially flat.

  • ▸The carb-load effect dominates: meals with 110g+ total carbs averaged +45.1 mg/dL — 79% above the light-carb (0–40g) baseline of +25.2 mg/dL (n=1,678 vs n=51,664).
  • ▸Rice is broccoli's biggest pairing penalty: broccoli with rice averaged +39.5 mg/dL vs +27.0 mg/dL alone — a +12 mg/dL jump across 7,541 logs (high confidence).
  • ▸Cheese is essentially neutral: broccoli with cheese or cheese sauce averaged +28.1 mg/dL vs +27.0 mg/dL alone (+1 mg/dL, n=17,310). The classic broccoli-cheddar combo doesn't behave like a high-spike meal.
  • ▸Morning timing lowers the spike: meals before 10 am averaged 25% lower peaks (CI: −7.99 to −7.12 mg/dL, n=5,454 vs n=65,103, p<0.001).
● Signos Rules

Three citable insights from this recipe's data

Rule 1
"The Starch-Side Penalty"
+79% peak
When broccoli appears in a meal with 110g+ of carbs, the glucose peak climbs to +45.1 mg/dL — 79% above the light-carb baseline of +25.2 mg/dL (n=1,678 vs. n=51,664). The cruciferous family pattern is consistent: broccoli, like cauliflower and kale, contributes essentially no fast-digesting carbs of its own. Every point of escalation comes from the rice, pasta, or potato sharing the plate. Rice is the worst single offender at +12 mg/dL over baseline.
Rule 2
"The Cheese Exception"
+1 mg/dL vs. broccoli alone
Broccoli with cheese or cheese sauce averaged +28.1 mg/dL — just +1 mg/dL above the broccoli-alone baseline of +27.0 mg/dL (n=17,310, high confidence). Cheese contributes near-zero net carbs and adds fat that mildly slows gastric emptying. The classic broccoli-cheddar pairing is, in our data, the cleanest carb-companion swap available — provided no rice, pasta, or potato is also on the plate.
Rule 3
"The Morning Edge"
−25% peak
Broccoli logged before 10 am averaged 25% lower glucose peaks than the same food logged later in the day (n=5,454 morning logs vs. n=65,103 non-morning, p<0.001). Breakfast meals containing broccoli averaged +23.5 mg/dL — the lowest of any meal-time slot — compared to +30.6 mg/dL for dinner and +33.7 mg/dL for afternoon snacks. Earlier insulin sensitivity likely drives the gap, though the effect is observational.
● Curious about your own?

Curious how your body responds to broccoli specifically?

Across 78,005 logged broccoli meals, the average glucose peak was +29.4 mg/dL — but the IQR spans 25 mg/dL (p25: +12, p75: +37), meaning individual responses vary enormously. 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 +27 mg/dL.

Driver 1
Meal-level carbohydrates (~60g+ when paired)
+16 mg/dL
The dominant lever: meals with ≥60g carbs ran 63% higher than low-carb logs (p<0.001, n=11,754 vs. n=51,664). Broccoli itself is nearly carb-free; this effect is entirely from what it's eaten with.
Driver 2
Caloric load and meal composition (avg 320 kcal alone vs 510 kcal paired)
+5 mg/dL
Single-item broccoli logs averaged +31.6 mg/dL on 320 kcal; multi-item meals averaged +29.3 mg/dL on 510 kcal. Bigger plates deliver more digestible carbs alongside the florets.
Driver 3
Individual glucose variability (IQR 25 mg/dL)
+6 mg/dL
The interquartile range spans 25 mg/dL (p25: +12, p75: +37 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 +25.2 mg/dL. Others spike +45.1. The only way to know how you'll spike is to measure with a Signos CGM.

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● What surprised us
What surprised us about broccoli is how cleanly the cruciferous-family pattern shows up in the data. Across 78,005 logs, broccoli alone averaged +27 mg/dL — essentially flat. Pair it with cheese and you're still at +28 mg/dL. But add rice and the same plate jumps to +39.5 mg/dL. The vegetable doesn't move the needle; the starch beside it does almost all the work. The cohort number of +29.4 mg/dL is really a weighted average of "broccoli alone" and "broccoli on top of rice."
— Signos Data Science Team

Why this happens, physiologically

Broccoli is a near-zero-carb cruciferous vegetable — a 1-cup serving contains roughly 6g of total carbs, most of which is fiber — so its modest cohort peak of +29.4 mg/dL across 78,005 logs is driven almost entirely by what's on the plate alongside it. The single biggest lever is total meal carb load: meals with ≥60g of carbs ran 63% higher than the low-carb baseline (p<0.001), and the carb-bucket analysis shows a near-linear escalation from +25.2 mg/dL in light (0–40g) meals all the way to +45.1 mg/dL in very-heavy (110g+) meals — a 79% jump. Cooking method (steamed vs. roasted vs. raw) shifts the response by less than 1.5 mg/dL across all forms. The mechanism is observational, not causal, but the pattern is consistent across the cruciferous family — broccoli, cauliflower, kale, and brussels sprouts all behave the same way: glucose-flat alone, amplifiers of whatever starch they're eaten with.

● Three mechanisms explain broccoli's glucose range

Meal carb load, fiber-driven gastric slowing, and time-of-day each drive measurable shifts in broccoli's glucose response

  1. Mechanism 1
    +63%
    High carb co-load
    Meals logged with ≥60g total carbs showed peaks 63% above the low-carb baseline (n=11,754, p<0.001). Broccoli itself adds almost no fast-digesting carbs — every point of that 63% comes from rice, pasta, or potato on the plate.
  2. Mechanism 2
    +15%
    Fiber-driven response
    High-fiber meals (≥5g fiber) showed peaks 14.7% higher across n=49,714 logs (CI: +3.22 to +4.58 mg/dL). The directional sign reflects that fiber-heavy meals in our cohort tend to be larger, not that fiber raises glucose — the larger meal context dominates.
  3. Mechanism 3
    −25%
    Morning timing
    Broccoli meals logged before 10 am ran 25% below the rest-of-day average (n=5,454, p<0.001). Earlier insulin sensitivity is the most likely driver, though the effect is observational, not causal.
● Fit Check
Broccoli is one of the lowest-glycemic vegetables on the Harvard table — its peak depends almost entirely on the starch beside it.
✓ This is for you if
  • ▸You eat broccoli alone or as the bulk of the plate. Logs of broccoli alone average +27 mg/dL, with 38.5% of responses in the low range.
  • ▸You pair broccoli with cheese instead of starch. Broccoli with cheese sauce averaged +28.1 mg/dL — just +1 mg/dL over broccoli alone in 17,310 matched logs.
  • ▸You keep total meal carbs under 40g. Light-carb broccoli meals averaged just +25.2 mg/dL across 51,664 logs — the lowest carb bucket in the cohort.
  • ▸You eat broccoli at breakfast or before 10 am. Morning broccoli meals averaged +23.5 mg/dL — 25% lower than the rest-of-day average.
✗ Not for you if
  • ▸You pile broccoli on top of a big bowl of rice. Broccoli with rice averaged +39.5 mg/dL across 7,541 logs — a +12 mg/dL jump over broccoli alone.
  • ▸You build broccoli into a high-carb meal (110g+ carbs). Very-heavy-carb meals with broccoli average +45.1 mg/dL — 79% above the light-carb baseline.
  • ▸You order broccoli stir-fry with a rice or noodle base. That combination averaged +38.2 mg/dL across 839 logs — +11 mg/dL over broccoli alone.
  • ▸You expect broccoli to neutralize a starchy plate. It won't — adding broccoli to rice or pasta doesn't lower the spike from the starch.
● How it fits your day

Calorie band and pairings (member-measured)

Per serving
55–510 kcal
Ranges from a 1-cup steamed side (~55 kcal) to a full broccoli-and-rice plate (~510 kcal); single-item logs averaged 320 kcal.
● Pair before
  • ▸Pair broccoli with cheese or eggs instead of starch: cheese pairing kept the peak at +28.1 mg/dL vs. +39.5 mg/dL with rice (n=17,310 vs. n=7,541).
  • ▸Keep total meal carbs under 40g: light-carb broccoli meals averaged +25.2 mg/dL vs. +45.1 mg/dL in the 110g+ carb bucket — a 79% escalation.
● Pair after
  • ▸Time a 15–20 min walk after high-carb broccoli meals (e.g. broccoli over rice or stir-fry with noodles), which averaged +38–40 mg/dL.
  • ▸If dinner is broccoli-and-rice heavy, note that dinner broccoli logs averaged +30.6 mg/dL vs. breakfast at +23.5 mg/dL — favor morning timing when possible.
● Avoid pairing
  • ▸Avoid stir-fry on a rice or noodle base: that pairing added +11 mg/dL over broccoli alone (treatment mean +38.2 mg/dL, n=839).
  • ▸Avoid stacking broccoli on a baked potato or mashed potato — potato pairings added +10 mg/dL above the broccoli-alone baseline in 6,157 matched logs.
● 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 broccoli compares to other cruciferous and low-GI vegetables
Cauliflower Glycemic Index & Glucose Score
Cauliflower follows the same cruciferous-family pattern — glucose-flat alone, amplifier of whatever starch it's beside.
Kale Glycemic Index & Glucose Score
Kale shares broccoli's near-zero glycemic load — the leafy-green version of the same starch-companion story.
Spinach Glycemic Index & Glucose Score
Spinach is another low-GI vegetable where the carb companion drives the spike, not the leaves.
Brussels Sprouts Glycemic Index & Glucose Score
Brussels sprouts round out the cruciferous family with the same pattern: low GI on their own, amplifier when roasted with a starchy side.
Carrots Glycemic Index & Glucose Score
Carrots — a non-cruciferous low-GI vegetable — give a useful contrast: a slightly higher published GI but similar cohort behavior.
Track Your Broccoli Response with Signos →
See how your glucose reacts to broccoli alone vs. on rice or in a stir-fry — CGM data, personalized to you.

Frequently Asked Questions

Methodology

This page draws on 78,005 logged broccoli meals from 14,584 unique Signos members, collected through the Signos production CGM platform, plus a single-item sub-cohort of 1,417 logs (3,722 in the recipe-builder analysis). 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 spike of +25 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 "broccoli" as a primary ingredient, excluding broccoli rabe, broccolini, Chinese broccoli (gai lan), and broccoli-cheddar soup. Any carb-pair pairing slot requires at least 100 matched meals before it appears in the recipe builder.

Limitations

  • Self-reported portion sizes introduce measurement error — a logged "1 cup" of broccoli may vary significantly in actual weight, affecting per-serving estimates.
  • Cohort skews health-motivated; Signos members actively tracking glucose tend to eat more mindfully than the general population, so real-world average spikes may differ.
  • The roasted broccoli sub-cohort (n=485, single-item) carries medium confidence; treat its delta vs. steamed (+0.1 mg/dL) as directional only.
  • The stir-fried broccoli form did not meet the minimum-cohort threshold and was suppressed from the recipe builder. Members who log stir-fried broccoli tend to also log a rice or noodle base, which is captured separately under the carb-pair slot.
  • Modifier analyses reflect meal-level correlations, not controlled feeding trials — causality cannot be established from observational CGM data alone.
  • Cohort logs likely under-report sides — a meal logged as "broccoli" alone sometimes included unlogged rice or starch — which is why the broccoli-alone mean of +27 mg/dL still sits above the published GL=1 expectation.
● Get your own data

See your own broccoli response

Across 78,005 logged broccoli meals, the average glucose peak was +29.4 mg/dL — but the IQR spans 25 mg/dL, meaning your personal response could land well above or below that. What you pair with broccoli matters too: rice adds +12 mg/dL, while cheese adds just +1 mg/dL. A CGM shows you exactly where you land and which builds work best for your biology.

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