Cornflakes with milk
Cornflakes score 81 on the GI scale, near the top of the international tables. A real bowl is two cups, about 46 g of carbs before the milk.
- Digestible carbs
- 57 g
- GI
- 73
- Glycemic load
- 42
- In cans of cola
- 1.9
Cornflakes score 81 on a scale where pure glucose is 100, one of the highest numbers for any breakfast in the international tables. Two cups with milk carries about 57 g of available carbs.
Rolled oats with berries and walnuts carries well under half the load, since rolled oats score 55 and the bowl has less starch in it.
What the hill looks like
Here's the meal next to its swap in our teaching model, drawn for a healthy adult from published averages. Your own curve will differ, but the gap between the two is the point.
- Cornflakes with milk peaks near 118 mg/dL (6.6 mmol/L) at 50 minutes and is 101 at two hours.
- Rolled oats with berries and walnuts peaks near 100 mg/dL (5.6 mmol/L) at 50 minutes and is 94 at two hours.
A teaching model built from published averages for a healthy adult, not a prediction for you. People eating the same meal can differ a lot. How the model works
What would flatten it
- Make it smaller. Half the starch is half the load, since the load is carbs times GI.
- Walk for 10 minutes after. In 41 adults with type 2 diabetes, 10-minute walks after each meal made the rise 12% smaller than one daily walk, and 22% smaller after dinner.
- Eat the protein and vegetables first. The same meal with the carbs 10 minutes later lowered the peak by more than 40% in 15 people with prediabetes.
- Swap the drink. Any sweet drink on the side adds its whole load, and water adds none.
Run this meal in the simulator, switch on a walk or carbs last, and watch where the sugar goes.
What the numbers rest on
GI worked out from its parts.
- Cornflakes, 1 cup x 2: 46.4 g digestible carbs from USDA Nutritive Value of Foods, item 457, p. 40: KELLOGG’S, 1 cup (28 g). GI 81, Atkinson 2008 Table 1, Cornflakes.
- Whole milk, 1 cup: 11 g digestible carbs from USDA Nutritive Value of Foods, item 118, p. 20: Whole (3.3% fat), 1 cup (244 g). GI 39, Atkinson 2008 Table 1, Milk, full fat.
This is about blood sugar for people without diabetes. If you take insulin or a sulfonylurea, your targets and meal plan come from your prescriber.
The 100 meals that raise blood sugar most · The 100 that keep it steady
7 sources
- US Department of Agriculture, Agricultural Research Service, Nutritive Value of Foods, Home and Garden Bulletin 72, 2002ars.usda.gov
- Atkinson FS, Foster-Powell K and Brand-Miller JC, International tables of glycemic index and glycemic load values, Diabetes Care, 2008pmc.ncbi.nlm.nih.gov
- University of Sydney, Glycemic Index Research and GI Database, accessed November 15, 2026glycemicindex.com
- Sydney University's Glycemic Index Research Service (Sydney, Australia), unpublished observations, via the University of Sydney GI databaseglycemicindex.com
- Reynolds AN and others, Advice to walk after meals is more effective for lowering postprandial glycaemia in type 2 diabetes than advice that does not specify timing, Diabetologia, 2016pubmed.ncbi.nlm.nih.gov
- Shukla AP and others, The impact of food order on postprandial glycaemic excursions in prediabetes, Diabetes, Obesity and Metabolism, 2019pubmed.ncbi.nlm.nih.gov
- Hutchins KM and others, Continuous glucose monitor overestimates glycemia, American Journal of Clinical Nutrition, 2025pmc.ncbi.nlm.nih.gov
