Instant Porridge Curbs Lunch Calories in Study

A small US trial found that instant porridge at breakfast led participants to eat 85 fewer calories at lunch than ready-to-eat oat cereal.

Updated on Nov. 3, 2026 in Nutrition

Gouache-painted editorial illustration of a bowl of thick porridge on a simple tabletop with a spoon, rendered in muted earthy tones. — Participants who ate instant porridge at breakfast consumed 85 fewer calories at lunch than those who ate ready-to-eat oat cereal, according to a small US trial. AI Illustration. Upload story photo >

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Do you choose your breakfast partly based on how full it keeps you?

Researchers testing 48 US adults found that participants reported feeling fuller after an instant porridge breakfast and ate 85 fewer calories at lunch four hours later than after an equal-calorie ready-to-eat oat cereal. The study was published in the Journal of the American College of Nutrition.

Why it matters

The findings suggest that the form and composition of breakfast oats may influence appetite and later food intake, not only total calories. Because the trial was small and measured appetite and a single subsequent meal rather than weight change, its implications for long-term weight management remain unclear.

The evidence is a small controlled crossover trial of 48 adults, which found 85 fewer lunch calories after instant porridge than after ready-to-eat oat cereal with equal breakfast calories. It is unresolved whether these short-term appetite effects translate into lasting weight change, and the foods differed in composition so the specific cause is not established.

The players

Journal of the American College of Nutrition

A peer-reviewed academic journal that publishes research on the role of nutrition in health and disease.

PepsiCo

A multinational food and beverage company whose researchers took part in the study.

Aldi

A discount grocery chain that sells the instant porridge sachets used in the comparison, priced at 95p for a pack of 10.

The details

Each participant tried both breakfasts on separate visits at least one week apart, and reported fullness afterward. Researchers pointed to differences in beta-glucan content and the thickness of the prepared breakfasts as possible reasons, though the two foods differed in several ways.

Lunch was served four hours after breakfast on each study visit.
Visits to the two breakfasts were separated by at least one week.

Health Landscape

The trial adds to research on whether the physical form of oat-based breakfasts, such as the thickness of prepared porridge, affects satiety compared with ready-to-eat cereals. It sits within a broader body of nutrition work testing how fiber-rich breakfasts such as oats influence later food intake.

For people choosing a breakfast, the study suggests that a thicker, instant porridge may leave some people feeling fuller than a ready-to-eat cereal with the same calories. Whether this helps with appetite control in daily life has not yet been tested over longer periods.

The takeaway

Breakfast form may matter as much as calories when it comes to feeling full. Readers interested in appetite can compare how thick or whole-grain their morning options are, while recognizing that this was a short study.