● Food Intelligence · Root Vegetable

Yam Glycemic Index and Calculate Your Own Glucose Response

Across 51 logs of yam eaten alone from 40 Signos members, the preliminary average glucose peak was +53.2 mg/dL — a directional read from a small cohort (cohortConfidence: low). In the broader 801-meal dataset, beef pairing tracked −9 mg/dL and morning timing ran nearly 20% lower than the rest-of-day baseline.

GS
Reviewed by Grace Shryack
Signos Proprietary Data·Updated May 2, 2026·10 min read

● Powered by Signos cohort dataLow confidence · n=51
The swap calculator below draws on 801 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
58
of 100
Signos Glucose Score
High Spike Risk
75% of members fall between +35 and +51 mg/dL
Predicted Curve · 3-hr window
1401001201401601800m30m60m90m120m150m180m+43
Peak
+43
mg/dL
Time in Range
100%
3hr window
Above 140
0m
danger zone
Swaps
0
applied
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● Key Findings · Does yam spike blood sugar?

Yes — preliminary data across 51 logs of yam eaten alone shows a mean glucose peak of +53.2 mg/dL, with 82.4% of responses exceeding +30 mg/dL. Cohort is small (n=51); treat as directional. Across 51 logs of yam eaten alone from 40 unique Signos members, the mean peak was +53.2 mg/dL — a high-spike read, but one that carries low confidence given the small sample. The IQR spans 32.5 mg/dL (p25: +37.5, p75: +70.0), signaling wide individual variation. In our broader 801-meal cohort, three levers shift the response: protein pairing (beef averaged −9 mg/dL across 102 logs), morning timing (−19.9% vs. rest-of-day baseline, n=89), and high carb load (+13% when meals hit ≥60g carbs, n=271). These are observational findings, not causal.

  • ▸Preliminary single-item data (n=51): 82.4% of logs exceeded +30 mg/dL and 76.5% landed in the high-spike tier — the highest concentration of any distribution bucket. Low-confidence; directional only.
  • ▸Beef pairing is the strongest modifier in the builder: treatment mean 35.8 vs. 44.8 mg/dL baseline (−9 mg/dL) across 102 matched logs — medium confidence.
  • ▸Morning timing (before 10am) tracked 19.9% lower than the rest-of-day baseline in the broader cohort (n=89 vs. n=642, p<0.001, CI: [−13.68, −3.52] mg/dL).
  • ▸High-carb meals (≥60g total carbs) spiked 13% higher than low-carb builds — a CI of [+1.6, +9.0] mg/dL across 271 matched meals (p<0.01).
● Signos Rules

Three citable insights from this recipe's data

Rule 1
"The Beef-Pairing Discount"
−9 mg/dL peak
Pairing yam with beef or stew meat dropped the average peak from 44.8 to 35.8 mg/dL — a −9 mg/dL reduction across 102 matched logs (medium confidence). It's the largest single modifier in the yam builder. Chicken (n=171) delivers a similarly reliable −7 mg/dL. Both proteins slow gastric emptying, spreading carb absorption over a longer window. Eggs (n=104) offer a smaller −4 mg/dL benefit; fish (n=70) shows minimal effect at −1 mg/dL.
Rule 2
"The Morning Edge"
−20% peak
Yam logs before 10am averaged 19.9% lower than the rest-of-day baseline in our broader 801-meal cohort (n=89 condition vs. n=642 baseline, p<0.001, CI: [−13.68, −3.52] mg/dL). Breakfast meal-time tracked +37.2 mg/dL versus +48.5 mg/dL for snack timing — a 30% gap from the same food. Morning insulin sensitivity is likely the mechanism, though the observational design cannot confirm causation.
Rule 3
"The Carb-Load Penalty"
+13% peak
Meals carrying ≥60g of total carbs spiked 13% higher than low-carb builds across 271 matched logs (p<0.01, CI: [+1.6, +9.0] mg/dL). Yam itself averages ~41g carbs per single-item log — add a side of rice, bread, or a starchy sauce and the combined carb load reliably pushes the response into the high-spike tier. The snack-time average (+48.5 mg/dL, n=63) likely reflects smaller, less-buffered meals that hit a higher carb density per calorie.
● Curious about your own?

Curious how your body responds to yam specifically?

Across 51 single-item yam logs from 40 Signos members, the preliminary mean peak hit +53.2 mg/dL — but the IQR spans 32.5 mg/dL (p25: +37.5, p75: +70.0). That's a wide individual range even in a small cohort. Your response depends on preparation, protein pairings, meal timing, and your own metabolic baseline. 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 +42 mg/dL.

Driver 1
Dense starch (~41g carbs per single-item log)
+53 mg/dL
Yam is a starchy tuber. Across 51 single-item logs the mean glucose peak ran +53.2 mg/dL — driven primarily by the high carb density with limited fiber or fat to slow absorption.
Driver 2
High total meal carb load (≥60g)
+5.5 mg/dL
Meals with ≥60g total carbs spiked 13% above the low-carb baseline (n=271 vs. n=296, p<0.01, CI: [+1.6, +9.0] mg/dL). Stacking yam with other starchy sides amplifies the response measurably.
Driver 3
Absence of protein or fat buffer
+8.5 mg/dL
The high-protein modifier (≥15g total protein) cut the broader cohort response by 12% (p<0.05, CI: [−9.87, −1.28] mg/dL). Eating yam without protein or fat removes the gastric-emptying brake.
● Which bucket are you in?

Some members spike +37.2 mg/dL. Others spike +53.2. 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 yam is the gap between the published GI and the cohort signal. GI 54 puts yam in the moderate tier — lower than sweet potato's GI 70 — yet across 51 single-item yam logs, the preliminary mean peak hit +53.2 mg/dL. The cohort is small enough that this gap could narrow with more data. What's clearer is the protein-pairing signal: beef (n=102) and chicken (n=171) both delivered 7–9 mg/dL reductions in matched logs — more leverage than fat pairings showed.
— Signos Data Science Team

Why this happens, physiologically

Across 51 logs of yam eaten alone from 40 Signos members, the preliminary mean glucose peak was +53.2 mg/dL — a high-spike reading, though the small cohort size (cohortConfidence: low) means this figure should be read directionally. The IQR spans 32.5 mg/dL (p25: +37.5, p75: +70.0), confirming substantial individual variation. In the broader 801-meal cohort, protein pairings were the dominant lever: high-protein meals (≥15g) cut the response by 12% (CI: [−9.87, −1.28] mg/dL, p<0.05), and the morning meal-time window ran 19.9% below the rest-of-day baseline (n=89, p<0.001). High-carb meal contexts pushed in the opposite direction, +13% above the low-carb baseline. All effects are observational from matched-pair Welch's t-tests.

● Three mechanisms drive yam's glucose range

Protein pairing, meal timing, and total carb load together explain the wide preliminary cohort spread from +37 to +70 mg/dL

  1. Mechanism 1
    −12%
    Protein buffer
    High-protein pairings (≥15g) cut the broader cohort response by 12% (p<0.05, CI: [−9.87, −1.28] mg/dL). Beef (−9 mg/dL, n=102) and chicken (−7 mg/dL, n=171) both showed medium-confidence effects — the clearest levers in this dataset.
  2. Mechanism 2
    −20%
    Morning timing
    Before-10am logs ran 19.9% lower than the rest-of-day baseline (n=89, p<0.001, CI: [−13.68, −3.52] mg/dL). Breakfast timing averaged +37.2 mg/dL — 11 mg/dL below the snack-time average of +48.5 mg/dL.
  3. Mechanism 3
    +13%
    Carb-load penalty
    Meals with ≥60g total carbs spiked 13% above the low-carb baseline (n=271, p<0.01). Yam itself averages ~41g carbs per log — stacking a second starchy side crosses the threshold quickly.
● Fit Check
Yam's preliminary single-item data reads high — but protein pairings and morning timing are real levers in the broader dataset, and the GI 54 anchor is still moderate by published standards.
✓ This is for you if
  • ▸You pair yam with beef or chicken. Beef (n=102) tracked a treatment mean of 35.8 vs. 44.8 mg/dL baseline (−9 mg/dL); chicken (n=171) delivered −7 mg/dL — both medium confidence.
  • ▸You eat yam at breakfast or before 10am. Morning logs ran 19.9% lower than the rest-of-day baseline (n=89, p<0.001), and breakfast meal-time averaged +37.2 mg/dL across 110 logs.
  • ▸You keep total meal carbs under 40g. Light-carb builds (0–40g) averaged +40.9 mg/dL across 296 logs — versus +50.6 mg/dL at the very-heavy end (110g+ carbs, n=59).
  • ▸You opt for boiled or steamed yam. That's the most-supported preparation in the cohort (n=795 broader) at the +42 mg/dL anchor.
✗ Not for you if
  • ▸You eat yam alone as a snack. Snack-time logs averaged +48.5 mg/dL across 63 meals — the highest meal-time window in the dataset.
  • ▸You skip protein entirely. The no-protein baseline is 44.8 mg/dL; adding beef drops that to 35.8 mg/dL — a 20% reduction from the same serving.
  • ▸You build a high-carb meal around yam. Meals with ≥60g total carbs spiked 13% above the low-carb baseline (CI: [+1.6, +9.0] mg/dL, n=271).
  • ▸You assume the GI 54 label means low-spike. The preliminary single-item data (n=51) shows a mean of +53.2 mg/dL — treat yam as the starchy tuber it is, not a low-GI free pass.
● How it fits your day

Calorie band and pairings (member-measured)

Per serving
202–545 kcal
Single-item yam logs average 202 kcal with 41g carbs; multi-item meals containing yam average 545 kcal with 58g carbs across the broader 801-meal cohort.
● Pair before
  • ▸Add a protein like beef or chicken before eating: beef (n=102) dropped the average to 35.8 mg/dL vs. 44.8 mg/dL baseline (−9 mg/dL, medium confidence).
  • ▸Time yam for breakfast: morning logs ran 19.9% lower than the rest-of-day baseline (n=89, p<0.001) — the single cheapest timing lever available.
● Pair after
  • ▸A 15–20 min walk after eating helps clear circulating glucose — relevant given 82.4% of single-item yam logs exceeded +30 mg/dL in preliminary data.
  • ▸Avoid stacking a second starchy side: meals with ≥60g total carbs averaged 13% higher peaks than light-carb builds (n=271, p<0.01).
● Avoid pairing
  • ▸Snack-time yam without protein: snack logs averaged +48.5 mg/dL (n=63) — 11 mg/dL above breakfast timing and without the morning insulin-sensitivity advantage.
  • ▸High-carb builds (110g+ total carbs): these averaged +50.6 mg/dL across 59 logged meals — the highest carb-bucket average in the dataset.
● 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: Yam is a starchy root in the moderate-GI tier — here is how it compares to adjacent foods and what the broader CGM data says.

Frequently Asked Questions

Methodology

This page draws on Signos production CGM data logged between March 2025 and April 2026, covering 801 meals containing yam across 403 unique members (broader cohort). The page-primary cohort is the single-item subset: 51 logs of yam eaten alone from 40 unique members, with a mean peak of +53.2 mg/dL, a median of +54.0 mg/dL, and an IQR of 32.5 mg/dL (p25: +37.5, p75: +70.0). Because the single-item cohort falls below 100 logs, this page is flagged cohortConfidence: 'low' — all single-item figures should be read as preliminary and directional. Statistical comparisons between modifier groups use Welch's t-test on matched pairs; effects are cited with p-values and 95% confidence intervals where available. Cohort filtering restricts to meals with a measured glucose rise between 0 and 100 mg/dL (ppgr_case='regular'). Yam logs were identified via regex matching on the canonical food name 'yam' and its plurals, excluding composite preparations (yam cake, yam chips). A minimum of 30 matched meals is required for any modifier to appear in the recipe builder (reduced from the standard 100 threshold given the smaller overall yam cohort); many form-preparation slots (roasted, mashed) fall below even this threshold and are flagged confidence: 'fail'.

Limitations

  • Single-item cohort is n=51 — below the 100-meal minimum for medium confidence. All single-item figures are preliminary and directional; do not treat the +53.2 mg/dL mean as an established benchmark.
  • In US grocery stores, 'yam' labels often refer to orange-fleshed sweet potato varieties, not true yam (Dioscorea spp.). The cohort likely mixes both, which may inflate variance and affect comparisons to GI 54.
  • Self-reported portion sizes introduce noise — a 'yam' log may range widely in weight and carb content across different members.
  • Preparation sub-cohorts (roasted n=5, mashed n=1) are far too small for any reliable estimate; roasted yam's apparent −14 mg/dL gap is illustrative, not citable.
  • Cohort skews health-motivated; Signos members actively monitoring glucose tend to be more metabolically aware than the general population, so average responses may be lower than a representative sample would show.
  • All findings are observational from matched-pair analysis, not controlled trials — confounders such as activity levels, sleep quality, and concurrent medications are not controlled.
● Get your own data

See your own yam response

Across 51 logs of yam eaten alone from 40 Signos members, the preliminary average peak was +53.2 mg/dL — but the IQR spans 32.5 mg/dL. Protein pairings like beef shift the outcome by 9 mg/dL in matched logs; morning timing shifts it by nearly 20%. Only a CGM tells you exactly where you land and which lever works for your biology.

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