Food Intelligence · Sweetener

Sugar Glycemic Index and Calculate Your Own Glucose Response

Across 5,252 single-item sugar logs from 2,602 Signos members, the average glucose peak was +27.6 mg/dL — the textbook GI-65 sweetener that every other sweetener gets benchmarked against. The vehicle does most of the work: a teaspoon stirred into coffee averages +37 mg/dL in matched-pair logs (n=8,136), in tea climbs to +41 (n=1,740), and on fruit barely budges from baseline (+31 mg/dL, n=4,650).

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Reviewed by Grace Shryack
Signos Proprietary Data·Updated May 20, 2026·10 min read

● Powered by Signos cohort dataHigh confidence · n=5,252
The swap calculator below draws on 43,229 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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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
41
of 100
Signos Glucose Score
Moderate Spike Risk
75% of members fall between +25 and +35 mg/dL
Predicted Curve · 3-hr window
1401001201401601800m30m60m90m120m150m180m+30
Peak
+30
mg/dL
Time in Range
100%
3hr window
Above 140
0m
danger zone
Swaps
0
applied
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● Key Findings · Does sugar spike blood sugar?

Yes — for the majority of members, with an average peak of +27.6 mg/dL across 5,252 single-item sugar logs from 2,602 Signos members. Across 5,252 logged meals where sugar was the focus, the mean glucose peak was +27.6 mg/dL and the median +23 mg/dL — moderate territory, and notably lower than the +35.5 mg/dL average we measured for honey on its own page. In the broader 43,229-log cohort that includes sugar paired with other foods, the mean climbs to +31.6 mg/dL because the surrounding meal compounds the response. Three levers drive most of the variance: vehicle (sugar in tea averages +41 mg/dL vs +31 on fruit), total meal carb load (very-heavy meals push the average to +49 mg/dL, a 74% escalation), and protein pairing (≥15g protein drops the peak by ~13%). The IQR spans 28 mg/dL (p25: +12, p75: +40) — the food itself is half the story, your meal context is the other half.

  • Across 5,252 single-item sugar logs from 2,602 members, the cohort mean was +27.6 mg/dL with a median of +23 mg/dL — 36.8% of logs cleared the +30 mg/dL threshold.
  • Vehicle is the dominant lever: sugar in tea averages +40.9 mg/dL across 1,740 matched logs, while sugar on fruit anchors at just +30.9 mg/dL (n=4,650) — a 32% gap from the same teaspoon.
  • Total meal carb load drives the spike harder than the sugar itself: very-heavy meals (110g+ carbs) averaged +48.8 mg/dL versus +28.1 in light-carb meals — a 74% escalation across 4 carb buckets.
  • Pairing with ≥15g protein dropped the peak by ~13% across 21,521 logged meals (CI: −4.9 to −4.1 mg/dL, p<0.001) — the largest pairing-buffer effect measured for sugar.
● Signos Rules

Three citable insights from this recipe's data

Rule 1
"The Vehicle Rule"
+12 mg/dL in tea vs plain
Sugar in tea averages +40.9 mg/dL across 1,740 matched logs versus a +29.0 plain-sugar baseline — a +12 mg/dL delta from the vehicle alone. Sugar in coffee tracks similarly (+36.9, n=8,136). Sugar on fruit lands lowest at +30.9 mg/dL across 4,650 logs (only +2 above plain) because fiber and water blunt the curve. The teaspoon hasn't changed — only what carries it.
Rule 2
"The Carb-Load Penalty"
+74% peak escalation
When sugar appears in meals carrying 110g+ of total carbs, the glucose response jumps to +48.8 mg/dL — a 74% escalation versus the light-carb baseline (+28.1 mg/dL, n=31,737). High-carb meals (≥60g total) ran ~59% above the low-carb cohort across 5,128 matched logs (CI: +15.83 to +17.08 mg/dL, p<0.001). The sugar isn't the headline driver; the surrounding carb load is.
Rule 3
"The Protein-Buffer Discount"
−13% peak
Pairing sugar with ≥15g of protein dropped the average peak by ~13% across 21,521 matched logs (CI: −4.9 to −4.1 mg/dL, p<0.001) — the largest pairing modifier measured for sugar. Dietary protein slows gastric emptying, blunting the rate of sucrose entry. The lever is real, but smaller than the +12 mg/dL bump you get from choosing tea over plain sugar — vehicle still wins.
● Curious about your own?

Curious how your body responds to sugar specifically?

Across 5,252 single-item sugar logs from 2,602 members, the IQR spans 28 mg/dL — from +12 mg/dL at the 25th percentile to +40 at the 75th. That's a wide range for a single teaspoon. Your response depends on the vehicle (coffee, tea, fruit, baked good), the surrounding meal carbs, and your baseline glucose at the time of eating. A CGM makes that variability visible in real time.

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Why this meal spikes

This meal stacks 3 independent spike drivers — together they account for +29 mg/dL.

Driver 1
Pure sucrose (~12g per tablespoon)
+27 mg/dL
A tablespoon of sugar carries ~12g of pure sucrose — 50/50 glucose and fructose, no fiber, no fat, no protein to slow it. Plain sugar averages +29.0 mg/dL across 24,401 logs; the molecule is doing exactly what GI 65 predicts.
Driver 2
Total meal carb load (≥60g at the same sitting)
+16 mg/dL
When total meal carbs hit ≥60g, peaks rose ~59% above the low-carb baseline (n=5,128, p<0.001, CI: +15.83 to +17.08 mg/dL). Very-heavy meals (110g+ carbs) hit +48.8 mg/dL — a 74% escalation vs light-carb meals.
Driver 3
High-sugar meal context (≥20g sugar at the meal)
+14 mg/dL
In 8,290 meals flagged for high total sugar content (≥20g), peaks ran ~53% above the low-sugar baseline (CI: +13.63 to +14.66 mg/dL, p<0.001) — when sugar stacks with other sugary items, the curve compounds rather than averages.
● Which bucket are you in?

Some members spike +28.1 mg/dL. Others spike +48.8. 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 sugar is how little the spoonful itself matters compared to what carries it. Across 5,252 single-item sugar logs, the mean peak was +27.6 mg/dL — squarely moderate, almost identical to plain Greek yogurt. But in tea the same teaspoon climbs to +41 (n=1,740); on fruit it barely moves from baseline (+31, n=4,650). The teaspoon is constant; the vehicle is the variable. Most 'is sugar bad for you?' questions are really 'is what I put sugar in bad for me?'
Signos Data Science Team

Why this happens, physiologically

Sugar produces a mean peak of +27.6 mg/dL across 5,252 single-item logs from 2,602 members — a moderate response with a wide IQR of 28 mg/dL (p25: +12, p75: +40) that points to context as the dominant driver. Three levers explain most of that range. First, the vehicle: in matched-pair logs, sugar in tea averages +40.9 mg/dL while sugar on fruit lands at +30.9 — a +10 mg/dL gap from the same teaspoon, driven by what the surrounding food does to gastric emptying. Second, total meal carb load: light-carb meals averaged +28.1 mg/dL while very-heavy meals (110g+ carbs) hit +48.8 — a 74% escalation across 4 carb buckets. Third, protein pairings — meals with ≥15g protein ran ~13% lower than the no-protein baseline across 21,521 matched logs. These effects are observational from matched-pair Welch's t-tests, not controlled trials.

● Three mechanisms drive sugar's glucose range

Vehicle, total carb load, and protein pairings together explain the gap between sugar's lowest- and highest-spike contexts in the cohort

  1. Mechanism 1
    +12 mg/dL
    Vehicle escalation
    Vehicle is the single biggest lever. Sugar in tea averaged +40.9 mg/dL (n=1,740); plain sugar anchored at +29.0 (n=24,401). The +12 mg/dL gap traces to how fast the sucrose hits the bloodstream when nothing else slows it.
  2. Mechanism 2
    +74%
    Carb-load escalation
    Total meal carb load is the second-biggest lever. Light-carb meals (0–40g) averaged +28.1 mg/dL while very-heavy meals (110g+, n=771) hit +48.8 — a 74% escalation. The teaspoon of sugar isn't the headline driver; the surrounding load is.
  3. Mechanism 3
    −13%
    Protein-buffer effect
    Meals with ≥15g of protein at the same sitting ran ~13% lower than the no-protein baseline across 21,521 matched logs (CI: −4.9 to −4.1 mg/dL, p<0.001). Dietary protein slows gastric emptying, blunting the rate of sucrose entry.
● Fit Check
Sugar lands in the moderate spike zone for most members — the vehicle and meal context shift that outcome more than the type or form of sugar you choose.
This is for you if
  • You sprinkle sugar on fruit. The on-fruit vehicle averages +30.9 mg/dL across 4,650 logs (option mean 30.9 vs default 29.0) — only +2 above plain sugar.
  • You keep total meal carbs light (0–40g). Light-carb meals averaged just +28.1 mg/dL across 31,737 logs — versus +48.8 mg/dL when total carbs exceed 110g.
  • You pair sugar with ≥15g of protein. Across 21,521 matched logs, protein pairings ran ~13% lower than the no-protein baseline (CI: −4.9 to −4.1 mg/dL, p<0.001).
  • You eat sugar at snack time rather than dinner. Snack-time logs averaged +28.6 mg/dL across 8,681 meals — versus +33.4 at dinner (n=5,897) and +35.4 at night (n=514).
Not for you if
  • You add sugar to tea. The in-tea vehicle averages +40.9 mg/dL across 1,740 logs — a +12 mg/dL delta from the plain-sugar baseline, the highest-spike vehicle measured.
  • You eat sugar as part of a high-carb meal (≥60g total carbs). That load lifts the response by ~59% — a +15.83 to +17.08 mg/dL increase above baseline across 5,128 matched logs (p<0.001).
  • You consume sugar alongside ≥20g of other sugar at the same meal. The high-sugar modifier raises the peak by ~53% — a CI of +13.63 to +14.66 mg/dL across 8,290 matched logs.
  • You eat sugar as a night snack. Night-snack logs averaged +35.4 mg/dL (n=514) — the highest meal-time window, about 7 mg/dL above snack-time.
● How it fits your day

Calorie band and pairings (member-measured)

Per serving
102–404 kcal
Single-item sugar logs averaged 102 kcal across the 9,879-meal cohort; mixed meals where sugar was paired with other items ran higher, around 404 kcal.
Pair before
  • Pick the on-fruit or in-lemonade vehicle: on fruit averages +30.9 mg/dL vs +40.9 in tea (n=4,650 vs 1,740) — the largest single move you can make.
  • Add a protein buffer (≥15g): drops the peak ~13% across 21,521 matched logs (CI: −4.9 to −4.1 mg/dL).
Pair after
  • A 20-min walk within 30 min of eating blunts carb-driven peaks — especially relevant given the +49 mg/dL average in the very-heavy carb bucket.
  • Avoid stacking high-carb sides post-sugar: meals with ≥60g total carbs spiked ~59% higher than the low-carb baseline (n=5,128).
Avoid pairing
  • Adding sugar to tea: the in-tea vehicle averaged +40.9 mg/dL vs +29.0 plain — tea drinkers more often skip the milk-fat buffer.
  • Eating sugar at night: night-snack logs averaged +35.4 mg/dL (n=514) — the highest meal-time window, about 7 mg/dL above snack-time.
● 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 sugar compares to other sweeteners and where it shows up in everyday meals

Frequently Asked Questions

Methodology

This page is grounded in 5,252 single-item sugar logs (the primary cohort) plus 43,229 total logged meals containing sugar from approximately 9,070 unique Signos members, captured through the Signos production PPGR cohort. Data was filtered to meals with a measured glucose rise between 0 and 100 mg/dL (ppgr_case='regular') to exclude outliers and sensor artifacts. Statistical comparisons between modifier groups use Welch's t-test on matched pairs; all effects reported at p<0.05 minimum, with the dominant modifiers reaching p<0.001. We report the mean peak glucose rise of +27.6 mg/dL across the right-skewed single-item distribution — the median is a few mg/dL lower at +23 mg/dL, which is typical for this data shape. The single-item IQR spans 28 mg/dL (p25: +12, p75: +40). Sugar logs were identified via a regex cohort match on the canonical food name 'Sugar' with explicit compound-term exclusions: 'brown sugar', 'sugar-free', 'sugar cookie', 'sugar cone', 'sugar snap peas', 'sugar plum', and 'blood sugar' are all dropped because the bare term over-matches into unrelated foods and the medical term. A minimum of 100 matched meals was required for any vehicle or form option to appear in the recipe builder.

Limitations

  • Self-reported portion sizes introduce measurement error — a 'teaspoon of sugar' logged by one member may differ meaningfully in volume from another's.
  • The compound-exclusion regex is a best-effort filter; novel sugar-prefixed compound foods (e.g. new product launches) may slip through and require periodic regex maintenance.
  • Cohort skews health-motivated; Signos members are actively monitoring glucose, so general-population responses — particularly among people with greater insulin resistance — may differ.
  • Smaller form sub-cohorts (powdered, cane, lemonade) are at medium confidence (n=136–254 matched logs); the deltas are directionally consistent but should be interpreted with caution.
  • All findings are observational, not causal — confounders such as concurrent medications, activity levels, and sleep quality are not controlled for in the modifier analysis.
● Get your own data

See your own sugar response

Across 5,252 single-item sugar logs from 2,602 members, the average glucose peak was +27.6 mg/dL — but the IQR spans 28 mg/dL (p25: +12, p75: +40). That's not noise; it's biology. Your vehicle, your carb load at the meal, even the time of day all shift the outcome measurably. Sugar on fruit anchors at +31 mg/dL in our matched-pair data; sugar in tea climbs to +41. Only a CGM tells you which end of that range you live on.

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