● Food Intelligence · Vegetable
Across 113,910 tomato logs from 17,597 Signos members — the largest single-vegetable cohort in the atlas — the average glucose peak was +31.6 mg/dL. But that headline number hides the real story: raw tomato on a salad averaged +31.0 mg/dL, while tomato sauce on a sandwich pushed peaks to +44.6 mg/dL and pizza to +42.2 mg/dL. The tomato isn't the spike — the bread underneath is.
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Barely on its own — tomato has a published GI of 33, and tomato on a salad averaged just +31.0 mg/dL across 29,244 logs. The cohort's +31.6 mg/dL headline is dominated by sauce-on-carbs meals. Across 113,910 tomato logs from 17,597 Signos members, the average glucose peak was +31.6 mg/dL — but that number is mostly noise from the bread and pasta sitting underneath. Raw tomato on a salad ran at +31.0 mg/dL, essentially flat against the +29.6 mg/dL alone-baseline. Where the spike actually lives: tomato on a sandwich, toast, or bruschetta averaged +44.6 mg/dL (+15 mg/dL over baseline, n=4,899); tomato sauce on pizza averaged +42.2 mg/dL (+13 mg/dL, n=1,742); tomato soup with crackers averaged +42.5 mg/dL (+13 mg/dL, n=2,175). The carb-load modifier confirms the pattern: ≥60g carbs lifted peaks 58% above the low-carb baseline. Tomato is a low-glycemic vehicle for whatever starch it accompanies.
Some members spike +27 mg/dL. Others spike +46.2. The only way to know how you'll spike is to measure with a Signos CGM.
Tomato is a low-glycemic food (published GI 33, GL 9) — a medium fresh tomato delivers roughly 4–5g of carbs, mostly fructose and glucose, plus 1.5g of fiber. Across 113,910 cohort logs the average peak was +31.6 mg/dL, but that number is dominated by meals where tomato accompanied a high-carb base. The single biggest lever measured was total meal carb load: meals with ≥60g of carbs ran 58% higher than the low-carb baseline (p<0.001), and the carb-bucket analysis shows a near-linear escalation from +27.0 mg/dL in light (0–40g carb) meals to +46.2 mg/dL in very-heavy (110g+) meals — a 71% jump. Two opposing levers worked in tomato's favor: morning-timed meals trimmed the response by 16% (n=11,494, p<0.001), and high-baseline-glucose logs ran 10% lower (a regression-to-the-mean effect). Fat and protein pairings showed essentially no independent effect (both <1% with high p-values), unusual for the atlas — most of the variance in tomato-meal spikes is upstream, in the carbohydrate base itself, not in what was eaten alongside.
This page draws on 113,910 tomato logs from 17,597 unique Signos members — the largest single-vegetable cohort in the atlas — 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 +28 mg/dL is a few mg/dL lower than the mean of +31.6 mg/dL, which is typical for this type of data. The food was identified in member logs using a regex that matched 'tomato' or 'tomatoes' as a primary ingredient, excluding tomato juice, paste, concentrate, powder, bisque, sun-dried preparations, and bloody mary cocktails. Any carb-pair pairing slot requires at least 100 matched meals before it appears in the recipe builder.