● Food Intelligence · Fruit

Nectarine Glycemic Index and Calculate Your Own Glucose Response

Across 2,493 single-item nectarine logs from 1,003 Signos members, the average glucose peak was +33.9 mg/dL — the modest stone-fruit signature, sitting between peach (+29.3) and apricot (+34.6). Layer a nectarine over yogurt or oatmeal and the matched-pair mean drops to +32.3 mg/dL; stack it into a 110g+ carb meal and the average climbs to +42.4 mg/dL.

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

● Powered by Signos cohort dataHigh confidence · n=2,493
The swap calculator below draws on 2,493 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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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
47
of 100
Signos Glucose Score
High Spike Risk
75% of members fall between +29 and +41 mg/dL
Predicted Curve · 3-hr window
1401001201401601800m30m60m90m120m150m180m+35
Peak
+35
mg/dL
Time in Range
100%
3hr window
Above 140
0m
danger zone
Swaps
0
applied
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● Key Findings · Do nectarines spike blood sugar?

Modestly — about half the time, with an average peak of +33.9 mg/dL across 2,493 single-item nectarine logs. In our cohort of 2,493 single-item nectarine logs from 1,003 unique members, the mean glucose peak was +33.9 mg/dL — placing nectarines mid-tier among stone fruits, a hair above peach (+29.3) and just below apricot (+34.6). The median was +31 mg/dL, and 25.9% of responses fell in the low-spike tier (≤20 mg/dL). Three levers drive the variance: total meal carb load (the dominant factor — a ≥60g carb meal amplifies the response by 28.4%), meal-level sugar content (≥20g adds 19.3% across 689 matched logs), and starting baseline glucose (members starting ≥110 mg/dL saw 15.7% lower peaks across 655 logs, p<0.001 — a counterregulatory pattern). The IQR spans 25 mg/dL (p25: +20, p75: +45), confirming wide individual variability.

  • ▸Carb load is the biggest lever: meals with ≥60g carbs spiked 28.4% higher than the low-carb baseline (p<0.001, n=316 vs. n=1,690).
  • ▸Going from a light (0–40g carb) to a very heavy (110g+) meal widens the average peak from +31.4 to +42.4 mg/dL — a 35% escalation.
  • ▸Nectarines on yogurt or oatmeal averaged +32.3 mg/dL across 328 matched logs — −2 mg/dL below alone (medium confidence).
  • ▸High starting baseline (≥110 mg/dL) was associated with 15.7% lower nectarine peaks across 655 logs (p<0.001) — a counterregulatory pattern.
● Signos Rules

Three citable insights from this recipe's data

Rule 1
"The Carb-Load Penalty"
+35% peak
Across 316 meals where total carbs hit 60g or more, glucose peaks ran 28.4% higher than the low-carb baseline (p<0.001). The full graded escalation runs further: very heavy meals (110g+ carbs, n=45) averaged +42.4 mg/dL vs. +31.4 mg/dL at the light end — a 35% swing. Even for a low-GI fruit like nectarine, stacking a second carb source — granola, oatmeal, toast — at the same sitting is the single largest modifier measured.
Rule 2
"The Yogurt-Layer Discount"
−2 mg/dL peak
Layering nectarines on yogurt or oatmeal averaged +32.3 mg/dL across 328 matched logs — 2 mg/dL below the +34.3 mg/dL nectarine-alone baseline (medium confidence). The protein and fat in Greek yogurt — and the soluble fiber in oatmeal — buffer the fruit's natural sugars marginally. The savory equivalent (grilled with chicken) tracked essentially neutral at +34.1 mg/dL across 306 logs, neither helping nor hurting.
Rule 3
"The High-Baseline Counter-Rule"
−15.7% peak
When members started a nectarine meal with baseline glucose ≥110 mg/dL, the peak ran 15.7% lower than the normal-baseline group across 655 matched logs (p<0.001, CI: [−7.5, −3.9] mg/dL). This is a counterregulatory response — the body suppresses additional glucose rise when already elevated. It's a useful pattern to know, but not a target to chase: chronically elevated baselines are the underlying concern.
● Curious about your own?

Curious how your body responds to nectarines specifically?

Across 2,493 single-item nectarine logs, the average glucose peak was +33.9 mg/dL — but the IQR spans 25 mg/dL, from +20 mg/dL at the 25th percentile to +45 mg/dL at the 75th. That's a wide range for a low-GI stone fruit. Your response depends on what else is on the plate, what time you eat, and your own baseline glucose. A CGM makes that variability visible in real time.

Learn how Signos works
Why this meal spikes

This meal stacks 3 independent spike drivers — together they account for +34 mg/dL.

Driver 1
Natural sugars (~11g carbs per medium fresh nectarine)
+18 mg/dL
A fresh nectarine carries roughly 11g of carbs, primarily fructose and glucose. This is the dominant driver of the +33.9 mg/dL single-item cohort mean — modest by fruit standards, consistent with a GI of 43.
Driver 2
Total meal carb load (≥60g at the meal level)
+9 mg/dL
Meals with ≥60g total carbs spiked 28.4% above the low-carb baseline (p<0.001, n=316 vs. n=1,690). Very heavy meals (110g+, n=45) pushed the average to +42.4 mg/dL — a 35% escalation vs. light-carb builds (+31.4 mg/dL).
Driver 3
High-sugar meal context (≥20g sugar at the meal level)
+6 mg/dL
In 689 meals flagged for high sugar content, peaks ran 19.3% higher than the low-sugar baseline (p<0.001, CI: [+3.38, +8.45] mg/dL). Pairing nectarines with sweet additions — yogurt with honey, granola — compounds the already-present fructose load.
● Which bucket are you in?

Some members spike +31.4 mg/dL. Others spike +42.4. The only way to know how you'll spike is to measure with a Signos CGM.

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● What's worth knowing
What's worth knowing about nectarines is how closely they shadow peaches in our cohort. Same GI (43 vs. 42), nearly identical mean (+33.9 vs. +29.3 mg/dL), and the same levers — carb load and meal context — explain most of the variance. The +4 mg/dL gap likely reflects portion or sugar-density variation rather than a true varietal difference. The cohort's lower-spike preparations are the same on both fruits: yogurt layering, savory grilling, snack-time eating. Across 715 snack-time nectarine logs, the average peak was +30.9 mg/dL — the lowest meal-time window in the dataset.
— Signos Data Science Team

Why this happens, physiologically

Nectarines produce a mean peak of +33.9 mg/dL across 2,493 single-item logs — moderate stone-fruit territory, consistent with a GI of 43 and a ~11g carb load per medium fruit. The IQR spans 25 mg/dL (p25: +20, p75: +45) and 50.3% of single-item logs exceeded +30 mg/dL. Two levers dominate the upper end of that range. First, total meal carb load: meals in the very heavy bucket (110g+ carbs) spiked +42.4 mg/dL on average — a 35% escalation vs. light-carb meals (+31.4 mg/dL). Second, meal-level sugar content: high-sugar logs (≥20g, n=689) ran 19.3% higher than the low-sugar baseline (p<0.001). Fat and protein pairings offered essentially no measurable buffering (p=0.63 and p=0.53 respectively) — nectarine's already-low carb dose leaves little spike to blunt. These findings are observational from matched-pair Welch's t-tests, not controlled trials.

● Three mechanisms drive nectarine's glucose range

Carb load, sugar content, and baseline glucose together explain the 35% escalation seen in the cohort

  1. Mechanism 1
    +35%
    Carb-load escalation
    Total meal carb load is the single biggest lever. Light-carb meals (0–40g) averaged +31.4 mg/dL; very heavy meals (110g+ carbs, n=45) averaged +42.4 mg/dL — a 35% escalation. The cohort's full graded response runs cleanly from light → medium → heavy → very heavy.
  2. Mechanism 2
    +19%
    High sugar effect
    Meals with ≥20g sugar ran 19.3% above the low-sugar baseline in 689 matched logs (CI: [+3.38, +8.45] mg/dL, p<0.001). Nectarine's natural fructose is amplified when the surrounding meal adds more fast-absorbing sugars.
  3. Mechanism 3
    −16%
    High baseline counter-effect
    When starting baseline glucose was ≥110 mg/dL, peaks ran 15.7% lower across 655 matched logs (p<0.001). This counterregulatory pattern reflects suppressed additional rise when glucose is already elevated — observational, not advice to chase.
● Fit Check
Nectarines are among the more forgiving fruits in the cohort data — peach-adjacent but a hair higher, with meal context the decisive variable.
✓ This is for you if
  • ▸You eat nectarines as a standalone snack. Snack-context logs averaged +30.9 mg/dL (n=715) — the lowest meal-time window in the cohort.
  • ▸You keep total meal carbs under 40g. Light-carb builds averaged just +31.4 mg/dL (n=1,690) vs. +42.4 mg/dL at the very heavy end — a 35% swing.
  • ▸You layer nectarines on Greek yogurt or oatmeal at breakfast. That combination averaged +32.3 mg/dL across 328 matched logs — −2 mg/dL below alone.
  • ▸You grill them in a savory salad with protein. Grilled-with-chicken logs averaged +34.1 mg/dL across 306 matched logs — essentially neutral vs. alone, no spike penalty added.
✗ Not for you if
  • ▸You regularly eat nectarines as part of a 60g+ carb meal. The high-carb modifier pushed peaks 28.4% higher than the low-carb baseline in 316 matched logs (p<0.001).
  • ▸You eat nectarines at lunch with carbs. Lunch logs averaged +37.1 mg/dL (n=611) vs. +30.9 mg/dL at snack time (n=715) — a consistent 6 mg/dL timing difference.
  • ▸You eat nectarines alongside a high-sugar meal (≥20g sugar). The high-sugar modifier raised peaks by 19.3% — a +3.4 to +8.5 mg/dL CI above baseline in 689 matched logs.
  • ▸You expect fat or protein pairings to dramatically lower the peak. Fat ≥15g and protein ≥15g both registered no significant effect (p=0.63 and p=0.53) — nectarine's modest carb load leaves limited spike to blunt.
● How it fits your day

Calorie band and pairings (member-measured)

Per serving
64–1,065 kcal
Single-item nectarine logs average 64 kcal (15g carbs); light-carb meals containing nectarines average 222 kcal; very heavy carb builds average 1,065 kcal. Pairings and meal context drive most of the spread.
● Pair before
  • ▸Keep total meal carbs under 40g: light-carb builds average +31.4 mg/dL vs. +42.4 mg/dL for very-heavy (110g+) — a 35% swing.
  • ▸Layer with Greek yogurt or oatmeal at breakfast: that combo averaged +32.3 mg/dL across 328 matched logs — 2 mg/dL below the alone baseline.
● Pair after
  • ▸A 10–15 min walk after eating helps clear circulating glucose, especially relevant if the nectarine was part of a 60g+ carb meal.
  • ▸Avoid stacking nectarines into a high-sugar dessert build: meals with ≥20g sugar averaged 19.3% higher peaks across 689 matched logs (p<0.001).
● Avoid pairing
  • ▸High-carb meal contexts (≥60g total carbs): these logs averaged a 28.4% higher peak — +6.4 to +11.4 mg/dL above the low-carb baseline in 316 matched meals.
  • ▸Eating nectarines at lunch with a heavy main: lunch logs averaged +37.1 mg/dL (n=611) — the highest meal-time window, ~6 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 nectarines compare to other stone fruits and low-GI snacks — and what the CGM data shows about each.

Frequently Asked Questions

Methodology

This page draws on Signos production CGM data logged between March 2025 and April 2026, covering a single-item cohort of 2,493 logs where nectarine was eaten alone, from 1,003 unique members. The page-primary numbers — cited in the dek, key findings, voice note, and CTAs — come from this single-item cohort, with a mean peak of +33.9 mg/dL, a median of +31 mg/dL, and an IQR of p25 +20 to p75 +45 mg/dL. The swap calculator draws on a modifier-table cohort (n=2,493) for matched-pair pairing deltas. Statistical comparisons use Welch's t-test on matched pairs; reported effects carry p<0.001 unless noted otherwise (high-sugar p<0.001, p=5.9e-6; high-fiber p=0.003). Cohort filtering restricts to ppgr_case='regular' meals with glucose rise 0–100 mg/dL. A minimum of 30 matched meals is required for modifier inclusion. GI=43 and GL=6 are sourced from the Harvard 100+ Foods table (serving basis: 140g), both verified=true.

Limitations

  • Self-reported portion sizes introduce noise — a 'medium nectarine' logged by one member may differ meaningfully in weight and sugar content from another's.
  • Cohort skews health-motivated; Signos members are actively monitoring glucose, so average responses may skew lower than a representative population sample.
  • Yogurt / oatmeal layering modifier is medium-confidence (n=328); the −2 mg/dL delta is plausible but carries wider uncertainty than the high-confidence headline.
  • Grilled-with-chicken modifier is medium-confidence (n=306); the essentially-neutral effect (treatment mean +34.1 vs. baseline +34.3) suggests no measurable benefit beyond expectation.
  • Fat-pairing (≥15g) and protein-pairing (≥15g) modifiers did not reach statistical significance (p=0.63 and p=0.53) and are not cited as actionable levers in the editorial content.
  • High-fiber modifier reaches only p=0.003 with n_baseline=210 — directional but the effect-size CI is wide ([+1.5, +6.9] mg/dL).
  • All findings are observational, not causal — confounders including concurrent medications, activity levels, and sleep quality are not controlled for.
● Get your own data

See your own nectarine response

Across 2,493 single-item nectarine logs, the average peak was +33.9 mg/dL — but the IQR spans 25 mg/dL (p25: +20, p75: +45). Carb load is the biggest amplifier: a very heavy meal pushes the average to +42.4 mg/dL, a 35% escalation above light-carb builds. Meal context matters too — layering on yogurt or oatmeal trims the matched-pair mean to +32.3 mg/dL. Only a CGM tells you exactly where your personal response lands.

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