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Tomato Season: The Low-GL Workhorse of the August Garden
By the GlycemicWise Data Editorial Team · Published 2026-08-07 · Last reviewed 2026-08-07 · Seasonal · 6-8 min read · Dietary reference only
August is peak tomato time. Fresh tomatoes are among the lowest-GL foods in the produce aisle — while ketchup, canned sauce, and juice tell a different story.
August Tomato
August is tomato season across most of the US — the month when garden and farm tomatoes actually taste like tomatoes. For anyone watching glucose, the timing is ideal: a raw red tomato carries about GL 1 per serving, with roughly 4g of carbs and a gram of fiber per medium fruit, plus lycopene and potassium.
On the food pages, tomatoes sit at the very bottom of the GL scale alongside the other non-starchy vegetables — they are one of the few foods you can treat as nearly free for glucose purposes.
Processed Tomato Trap
The fresh-versus-processed split is the real lesson of tomato season. Ketchup adds significant sugar per serving and climbs into Moderate GL. Sweetened canned tomato sauce and tomato juice behave similarly. Even 'healthy' packaged tomato products frequently carry added sugar — which is why reading the label matters more than the tomato itself.
Unsweetened crushed tomatoes or tomato paste used in cooking stay low-GL; the added sugar is what moves the number.
GlycemicWise data perspective
A quick check of our database: Tomatoes red ripe year round average comes in at GL 2 per 100g (Low GL). Across the 814 Vegetables and Vegetable Products foods GlycemicWise covers, 81% fall in the low-GL range.
Ways to Use the Bounty
Peak tomato is the moment for gazpacho (GL 1 per bowl), caprese with olive oil (GL 1–2, fat quality bonus), or simply sliced tomatoes with a little salt on a grilled-chicken plate. Tomatoes also replace high-GL condiments across the summer menu — fresh salsa on a burger instead of ketchup, tomato slices in the lunchbox — which is how a single low-GL food quietly improves the whole season's glucose picture.
Dietary reference — not medical advice. Information provided for educational purposes.