● Food Intelligence · Nuts & Seeds

Peanut Butter Glycemic Index and Calculate Your Own Glucose Response

Across 111,648 peanut butter logs from 15,672 members, the average glucose peak was +28.7 mg/dL — but eaten off a spoon the cohort holds at +27.1 mg/dL, while a PB&J pushes the average to +39.2 mg/dL and a meal with 110g+ of carbs reaches +44.2 mg/dL, a 70% escalation driven almost entirely by the bread, bagel, or pancake underneath.

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

● Powered by Signos cohort dataHigh confidence · n=111,648
The swap calculator below draws on 111,648 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
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
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● Key Findings · Does peanut butter spike blood sugar?

Mildly on its own — averaging +28.7 mg/dL across 111,648 logs, with 39.1% of meals falling under 20 mg/dL. The bread, bagel, or crackers underneath are what actually spike. Across 111,648 logged meals from 15,672 members, peanut butter averaged +28.7 mg/dL (median +25). Eaten off a spoon, the matched baseline holds at +27.1 mg/dL — but adding it to a PB&J sandwich pushes the peak to +39.2 mg/dL (+12 mg/dL, n=6,959), crackers to +36.9 mg/dL (+10 mg/dL), and a bagel to +35.9 mg/dL (+9 mg/dL). Carb-heavy meals (110g+) with peanut butter average +44.2 mg/dL — 70% above the light-carb baseline of +26 mg/dL. The peanut butter itself is glucose-mild (GI=14, GL=1); the bread is doing the work.

  • ▸PB&J is the headline pairing: peanut butter on a sandwich averaged +39.2 mg/dL across 6,959 matched logs — a +12 mg/dL jump over the off-a-spoon baseline of +27.1 mg/dL.
  • ▸Crackers add the second-largest penalty: peanut butter on crackers averaged +36.9 mg/dL (+10 mg/dL above baseline) across 3,357 logs — slightly worse than a bagel.
  • ▸Bagels and English muffins push peanut butter into the moderate-spike tier: +35.9 mg/dL on average, +9 mg/dL above baseline (n=1,777, high confidence).
  • ▸Celery is the only pairing that lowers the peak: ants-on-a-log averaged +24.6 mg/dL — −3 mg/dL below the spoon baseline across 2,577 matched logs.
● Signos Rules

Three citable insights from this recipe's data

Rule 1
"The Sandwich-Bread Amplifier"
+12 mg/dL vs. off a spoon
A PB&J sandwich pushes peanut butter from +27.1 mg/dL (off a spoon, n=74,301) up to +39.2 mg/dL across 6,959 matched logs — the largest single carb-pairing penalty we measured. The peanut butter contributes near-zero fast-digest carbs; the sandwich bread plus jelly is the entire delta. Toast adds a smaller +6 mg/dL, but a bagel or English muffin adds +9 mg/dL and crackers add +10 mg/dL — all driven by the refined-grain vehicle, not the nut butter.
Rule 2
"The Natural-vs-Flavored Fork"
−2.9 mg/dL natural vs. smooth default
Natural / no-added-sugar peanut butter averaged +24.9 mg/dL (n=2,708) — the lowest of any form measured and 2.9 mg/dL below the smooth/creamy default of +27.8 mg/dL. Powdered PB2-style (+25.6 mg/dL, n=4,295) and flavored honey/chocolate variants (+25.5 mg/dL, n=17,607) landed similarly low, likely because members reaching for those products tended to log them in lower-carb contexts (smoothies, oatmeal). Crunchy was indistinguishable from smooth at +28.2 mg/dL.
Rule 3
"The Celery Buffer"
−3 mg/dL vs. off a spoon
Ants-on-a-log — peanut butter on celery — was the only pairing in the cohort that produced a negative delta. The treatment mean was +24.6 mg/dL across 2,577 logs versus the +27.1 mg/dL spoon baseline, a −3 mg/dL drop with high confidence. Celery contributes essentially zero net carbs and adds water and fiber; the result is a meal that's slightly milder than the peanut butter alone — the one lunchbox staple that doesn't move the curve up.
● Curious about your own?

Curious how your body responds to peanut butter specifically?

Across 111,648 logged meals the average glucose peak was +28.7 mg/dL — but the IQR spans 24 mg/dL (p25: +15, p75: +39), meaning individual responses vary enormously. Your own result depends on the bread underneath, the form you reach for, and your own 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)
+13 mg/dL
The dominant lever: high-carb meals (≥60g) ran 51% above the low-carb baseline (CI +12.83 to +13.63 mg/dL, n=11,429 vs n=81,641, p<0.001). Peanut butter contributes near-zero fast-digest carbs, so this effect is entirely from the bread, bagel, or crackers it's eaten with.
Driver 2
Added sugar in pairings or sweetened forms
+10 mg/dL
High-sugar meals (≥20g) averaged +9.61 to +10.24 mg/dL above the low-sugar baseline (n=18,387 vs n=60,019, p<0.001). PB&J and honey/chocolate-flavored peanut butters drive most of the sugar exposure in this cohort.
Driver 3
Individual glucose variability (IQR 24 mg/dL)
+6 mg/dL
The interquartile range spans 24 mg/dL (p25: +15, p75: +39 mg/dL), meaning personal metabolic state — insulin sensitivity, microbiome, stress — accounts for a substantial share of any individual reading.
● Which bucket are you in?

Some members spike +24.6 mg/dL. Others spike +44.2. 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 peanut butter is how clean the additive math is. Off a spoon, 74,301 logs averaged +27.1 mg/dL. Add a sandwich and you're at +39.2. Add a bagel: +35.9. Add crackers: +36.9. The peanut butter doesn't really move — the bread, bagel, or cracker underneath is the entire spike story. The one exception is celery, which actually pulled the peak down to +24.6 mg/dL — the ants-on-a-log lunchbox finding holds up across 2,577 logs.
— Signos Data Science Team

Why this happens, physiologically

Peanut butter is a low-GI food (GI=14, GL=1) — high in fat (~16g per 2 tbsp) and protein (~7g) with only ~3g of net carbs per serving — so its baseline cohort peak of +28.7 mg/dL across 111,648 logs is driven almost entirely by what surrounds it. The single biggest lever measured is total meal carb load: high-carb meals (≥60g) ran 51% above the low-carb baseline (p<0.001), and the carb-bucket analysis shows a near-linear escalation from +26.0 mg/dL in light (0–40g carb) meals to +44.2 mg/dL in very-heavy (110g+) meals — a 70% jump. Added sugar in the pairing or in flavored peanut butter pushed responses 39% higher (≥20g sugar threshold, p<0.001). Two secondary levers pull in the opposite direction: a fasted/high-baseline state (≥110 mg/dL) reduced the response by ~12% — likely a regression-to-the-mean artifact — and protein co-pairing (≥15g) trimmed peaks by ~5%. The mechanism is observational, not yet causal, but the pattern is consistent with peanut butter's own fat and protein blunting its modest carb load while the bread underneath does the lifting.

● Three mechanisms explain peanut butter's glucose range

Meal carb load, added sugar in the pairing, and fat/protein co-ingestion each drive measurable shifts in peanut butter's glucose response

  1. Mechanism 1
    +51%
    High carb co-load
    Meals logged with ≥60g total carbs showed peaks 51% above the low-carb baseline (n=11,429 vs n=81,641, p<0.001). Peanut butter itself adds almost no fast-digest carbs — every point of that 51% comes from the bread, bagel, jam, or crackers it's eaten with.
  2. Mechanism 2
    +39%
    Added sugar in the pairing
    High-sugar meals (≥20g) averaged 39% higher than low-sugar baselines (n=18,387 vs n=60,019, p<0.001). The PB&J jelly layer and the honey/chocolate flavored peanut butters explain most of this — the sugar is the active driver, not the peanut butter.
  3. Mechanism 3
    −5%
    Protein co-ingestion
    Protein pairings ≥15g cut the response by ~5% (n=62,907, p<0.001). Peanut butter itself contributes ~7g of protein per 2-tbsp serving, and pairings like a glass of milk or a protein shake trim the peak modestly through delayed gastric emptying.
● Fit Check
Peanut butter is a low-GI food (GI=14, GL=1) that works well for glucose control — until the bread, bagel, or jelly on the plate around it doesn't.
✓ This is for you if
  • ▸You eat peanut butter on celery. The ants-on-a-log pairing averaged +24.6 mg/dL — the only pairing that pulled the peak below the off-a-spoon baseline of +27.1 mg/dL across 2,577 logs.
  • ▸You stir peanut butter into oatmeal, yogurt, or a smoothie. That pairing held flat at +27.0 mg/dL across 13,190 matched logs — essentially zero delta vs. eating it alone.
  • ▸You reach for natural / no-added-sugar peanut butter. Natural averaged +24.9 mg/dL — 2.9 mg/dL below the smooth default across 2,708 logs.
  • ▸You spread peanut butter on apple slices. Apple pairing added only +2 mg/dL across 2,225 matched logs — well below the +12 mg/dL sandwich penalty.
✗ Not for you if
  • ▸You make a PB&J sandwich. That pairing added +12 mg/dL over the off-a-spoon baseline across 6,959 matched logs — the single biggest carb-pairing penalty measured for peanut butter.
  • ▸You spread peanut butter on a bagel or English muffin. That combination averaged +35.9 mg/dL — a +9 mg/dL jump above baseline across 1,777 logs.
  • ▸You eat peanut butter on crackers. Crackers added +10 mg/dL above the spoon baseline across 3,357 matched logs.
  • ▸You smear peanut butter on pancakes or waffles. That pairing averaged +33.9 mg/dL — a +7 mg/dL delta over baseline in 601 matched logs.
● How it fits your day

Calorie band and pairings (member-measured)

Per serving
190–650 kcal
Ranges from a 2-tbsp scoop alone (~190 kcal) to a PB&J sandwich (~450 kcal) to a bagel or pancake build (~650 kcal); single-item logs averaged 220 kcal.
● Pair before
  • ▸Pair peanut butter with celery or apple slices: celery dropped the peak by −3 mg/dL and apple added only +2 mg/dL — the two lowest-impact pairings in the cohort.
  • ▸Choose natural / no-added-sugar peanut butter when possible: it averaged +24.9 mg/dL vs. +27.8 mg/dL for the smooth default (n=2,708, high confidence).
● Pair after
  • ▸Time a 15–20 min walk after a PB&J or peanut butter on a bagel — those builds averaged +35.9 to +39.2 mg/dL, the highest pairing spikes in the cohort.
  • ▸If you build peanut butter into breakfast, the morning timing slot averaged +28.1 mg/dL — about 4% lower than the rest of the day across 33,214 morning logs.
● Avoid pairing
  • ▸Avoid PB&J sandwiches if glucose control is the goal: that pairing added +12 mg/dL over the off-a-spoon baseline (treatment mean +39.2 mg/dL, n=6,959).
  • ▸Avoid stacking peanut butter on a bagel or crackers — bagels added +9 mg/dL and crackers added +10 mg/dL above baseline in matched-pair 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 peanut butter's glucose response compares to other nuts, spreads, and pairing partners
Almonds Glycemic Index & Glucose Score
Almonds are the closest tree-nut comparator to peanut butter — both are low-GI fat-and-protein dominant foods that move with the carb on the plate.
Banana Glycemic Index & Glucose Score
Banana averaged +38.8 mg/dL across 8,097 logs — and pairing it with peanut butter added only +4 mg/dL over the spoon baseline, suggesting the fat-and-protein envelope blunts the banana spike.
Cream Cheese Glycemic Index & Glucose Score
Cream cheese is the other high-fat spread members lean on — see how it stacks up against peanut butter when spread on the same bagel or toast.
Bagel Glycemic Index & Glucose Score
The bagel is the actual driver of the peanut-butter-on-bagel spike: see the bagel's own +35.9 mg/dL pairing average broken down across 1,777 matched logs.
Track Your Peanut Butter Response with Signos →
See how your glucose reacts to peanut butter on celery, in a smoothie, or in a PB&J — CGM data, personalized to you.

Frequently Asked Questions

Methodology

This page draws on 111,648 peanut butter logs from 15,672 unique Signos members, 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 spike of +25 mg/dL is a few mg/dL lower than the mean of +28.7 mg/dL, which is typical for this type of data. The food was identified in member logs using a regex that matched "peanut butter" and PB&J variants as a primary ingredient, excluding compound desserts (Reese's, peanut butter cups, peanut butter cookies, buckeyes). 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 "2 tbsp" of peanut butter may vary significantly in actual weight, 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 spikes may differ.
  • The pancake / waffle carb-pair sub-cohort is moderately sized (n=601) — its +7 mg/dL delta is high-confidence but the sample is the smallest of the carb-pair slots.
  • The flavored / sweetened form group (n=17,607) likely mixes honey, chocolate, and maple-flavored peanut butters into a single bucket — finer-grained splits would require additional regex labeling.
  • Modifier analyses reflect meal-level correlations, not controlled feeding trials — causality cannot be established from observational CGM data alone.
  • The high-baseline-glucose modifier (≥110 mg/dL, −12% effect) is partly a regression-to-the-mean artifact: members starting high have less room to spike. Treat the directional finding as descriptive rather than mechanistic.
● Get your own data

See your own peanut butter response

Across 111,648 logged meals from 15,672 members, peanut butter averaged +28.7 mg/dL — but the IQR spans 24 mg/dL, meaning your personal response could land well above or below that. What you spread it on matters too: a sandwich adds +12 mg/dL, a bagel adds +9, while celery actually drops the peak by −3. A CGM shows you exactly where you land and which builds work best for your biology.

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