Oatmeal, Frosted Cornflakes: Does Breakfast Affect Appetite-Related Hormones?

The global obesity epidemic continues to be a major cause for concern for patients and health care providers. Obesity’s negative consequences are well-documented and numerous; cardiovascular disease, type 2 diabetes, and certain forms of cancer. In previous studies, regular breakfast consumption has been correlated with lower BMI and improved cardio-metabolic risk profile. Furthermore, evidence suggests that low-energy density, high-fiber, and high-carbohydrate foods may be more satiating when compared to their alternatives.

The Annals of Nutrition & Metabolism has published a new study that looks at breakfast’s potential to affect satiety. This randomized, controlled crossover study evaluated the impact of high-fiber breakfast consumption on appetite and food intake in both normal (BMI < 25; N=18) and overweight (BMI > 27; N=18) individuals.

All subjects were assigned to consume each of the three different breakfast options on separate days, in random sequence. The options included high-fiber plain oatmeal cereal, non-fiber sugared corn flake cereal, or water. Additionally, all subjects were allowed one cup of decaffeinated coffee (with or without non-dairy creamer) or decaffeinated tea. All three options were equal in their total volume of fluid. Since acetaminophen is rapidly absorbed from the duodenum, but not at all from the stomach, 700 mg was added to all options to serve as a gastric emptying tracer.

Patients reported their feelings of fullness using a visual analog scale (0 - 100) at multiple time intervals until 3 hours after the meal start time. At these same time intervals, the researchers took and analyzed blood was drawn levels. At 3 hours, they were given a meal.

All subjects reported significantly higher feeling of fullness for at least 3 hours after oatmeal consumption, but did not if they had had corn flakes and water. All subjects ingested less of the test meal after oatmeal consumption than after corn flakes or water. Furthermore, overweight subjects ingested less of the test meal after consuming oatmeal than did their normal weight counterparts.

Leptin and glucagon levels were similar regardless of breakfast option. Insulin levels did not differ significantly between the two cereals, but were both elevated when compared to water. Peak glucose levels were significantly lower for oatmeal than for corn flakes, and both were higher than water.

The researchers suggest that oatmeal’s ability to slow gastric emptying makes it an idea breakfast food.