Introduction

Nearly 7% of the world population is obese¹ and about 66% of the adults in the United States are overweight or obese.² Obesity is associated with a number of adverse medical conditions including increased risk of gallbladder disease, hypertension, type 2 diabetes mellitus, coronary heart disease (CHD), osteoarthritis, cancer death and reduced life expectancy.^3–8 Obesity is also associated with adverse social and psychological consequences, including bias, discrimination and decreased quality of life.^9,10

More effective treatment strategies are urgently needed for obesity management. The total caloric intake or energy density of one’s diet appears to be associated with obesity^11–14 and a diet that induces a negative energy balance continues to be an important part of obesity management. Strategies to achieve the difficult task of eating less than desired include reduction of the energy density of foods by increasing food volume by the addition of fluids,^15,16 bulk^17–19 or their combination;²⁰ or by increasing satiety by various anorectic drugs or macronutrient combinations of high satiety value.

Satiety is positively associated with the protein, fiber and water content of foods and negatively with fat and palatability ratings.^21,22 However, within food groups, there may be as much as a twofold difference in satiety values, suggesting that certain foods promote greater satiety independent of macronutrient content or energy density. An egg is an example of such a food that has a 50% greater satiety index compared to white bread or ready-to-eat breakfast cereal.²¹ Compared to an isocaloric bagel breakfast of equal weight, an egg breakfast had a greater satiating effect, which translated into a lower caloric intake at lunch.²³ The resulting decrease in energy consumption lasted for at least 24 h after the egg breakfast.

This study was undertaken to exploit the short-term satiating benefits of an egg breakfast²³ for weight loss in a longer-term trial. The objectives were to determine if the incorporation of an egg breakfast in the diet by overweight or obese subjects would (1) induce reduced energy intake and unintentional weight loss, even when not attempting weight reduction; or (2) enhance weight loss when following a reduced energy diet. We compared the effects of an egg vs isocaloric bagel breakfast of equal weight on weight loss, indices of body size and composition, dietary compliance, food cravings and health-specific quality of life.Materials and methods

The study was approved by the institutional review boards at Pennington Biomedical Research Center and at Saint Louis University. Written informed consent was obtained from the participants. We certify that all applicable institutional and governmental regulations regarding the ethical use of human volunteers were followed during this research.