Oatmeal vs corn flakes

Key differences

• Oatmeal provides more protein per calorie: 3.6 g per 100 kcal, versus 1.5 g for corn flakes.
• Oatmeal has fewer calories: 71 kcal per 100 g, versus 384 for corn flakes, so the same calories come with more grams of food.
• Corn flakes have more fiber: 2.7 g per 100 g, versus 1.7 g for oatmeal.

Comparison per 100 g

Per typical serving

With typical servings, 200 g (7 oz) of oatmeal has about 142 kcal and 5.1 g of protein, and 30 g (1 oz) of corn flakes about 115 kcal and 1.8 g.

The typical serving is a common amount used for the math, not a recommendation. Ounces are rounded US equivalents; the values come from the database entries cited in the sources.

Which is more filling?

By our estimate, oatmeal is more filling per calorie than corn flakes: 5 versus 1 out of 5.

Both were measured in people in the Holt satiety index (1995), where white bread scores 100: oatmeal scored 209 and corn flakes 118. In that study oatmeal was more filling for the same calories.

• 5/5Oatmeal: Very low energy density; moderate fiber per calorie; high water content.
• 1/5Corn flakes: High energy density.

The 1 to 5 score is our own estimate: it starts at 1 point, adds points for low energy density, for protein and fiber per 100 kcal, and for the water in solid foods, and subtracts points for drinks with calories. It is useful for comparing foods with each other; it is not a measurement in people. Holt satiety index: Holt SH, Miller JC, Petocz P, Farmakalidis E. A satiety index of common foods. Eur J Clin Nutr. 1995;49(9):675-90.

When to choose each one

Oatmeal

• If you want more protein per calorie: 3.6 g per 100 kcal.
• If you want to eat more grams for the same calories: 71 kcal per 100 g.
• If you want more protein in a typical serving: 5.1 g in 200 g (7 oz).
• If you have nausea or fill up quickly: it carries our “Easy to digest” tag.

Corn flakes

• If you want to add fiber: 2.7 g per 100 g.
• If you prefer a lighter typical serving: about 115 kcal in 30 g (1 oz).

On a GLP-1 medication

Oatmeal. “Easy to digest”: a soft or low-fat food that many people tolerate well when they feel nauseous or get full quickly. “Low energy density”: plenty of volume for few calories; make sure it does not push protein foods off your plate.

Corn flakes. “High energy density”: a lot of energy in a small volume; when your appetite is very low, a small serving can help you meet your needs.

These are general guidelines, not medical advice: everyone tolerates foods differently.

Full food pages

• Oatmeal: every nutrient, frequently asked questions, and similar foods.
• Corn flakes: every nutrient, frequently asked questions, and similar foods.

Other comparisons

• Oatmeal vs quinoa
• Rolled oats vs corn flakes

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