Cornflakes: GI, GL, Carbs & Blood Sugar Impact
Glycemic index of cornflakes (81), glycemic load, carbs per bowl, and why cornflakes are a high-impact breakfast cereal for people with diabetes.
Do Cornflakes Raise Blood Sugar?
Cornflakes are among the highest common breakfast GIs — a published value around 81 — because the grain is heavily processed into quick-absorbing starch. Even a modest bowl (one cup, about 28 g) has a moderate-to-high GL.
How to Eat It
If you like breakfast cereal, look for wholegrain, higher-fiber options, keep the bowl small, and add protein (milk, yogurt, nuts) — or compare with rolled oats before choosing.
Nutrition Facts (Cornflakes)
| Nutrient | Per 100 g | Per serving |
|---|---|---|
| Calories | 357 kcal | 100 kcal |
| Carbohydrate | 84 g | 23.5 g |
| Fiber | 3.3 g | 0.9 g |
| Sugars | 8 g | 2.2 g |
| Protein | 7.5 g | 2.1 g |
| Fat | 0.4 g | 0.1 g |
Source: USDA FoodData Central (generic food item, per 100 g edible portion). Values may differ from brand-specific products.
Glycemic Index
Published GI: 81 (typical value).
Reported range: 75-92.
Evidence level: Moderate.
Note: Highly processed cereal; among the highest common breakfast GIs.
Sources: International Tables of Glycemic Index and Glycemic Load Values (2008/2021); University of Sydney GI Database (glycemicindex.com). GI values are reported relative to a glucose reference.
Learn more: What is GI? · What is GL? · GI vs GL
Estimated Glycemic Load
GL ≈ 18.3 per 1 cup (28 g).
Calculation: GI (81) × available carbohydrate per serving (22.6 g = 84 g − 3.3 g fiber) ÷ 100. Calculated by DMSafeHaven; formula per standard published GL methodology.
- Portion size
- Milk choice
- Other toppings
GI values can vary with variety, ripeness, preparation and testing conditions. The value above is a typical published figure, not a universal prediction for every individual or every serving.