Topical Area: Obesity, Energy and Macronutrient Metabolism
Objectives : A breakfast containing eggs (EB) can potentially provide a greater quantity of high quality protein. We previously reported (Study 1) that EB induces greater satiety and reduces lunch time energy intake (LTEI) compared to a breakfast without eggs (CB), but of equal energy density. However, this EB had a greater amount of protein. Hence, in Study 2 we compared EB and CB with equal energy density and protein quantity, but of differing protein quality. EB (higher protein quality) increased fullness, but did not reduce LTEI. For this study (Study 3), we used the breakfasts from Study 2, to compare the effect on fullness and LTEI, in subjects in negative energy balance, due to a weight loss diet.
Methods : In a crossover study, 30 sedentary women (18-44 y old) with overweight or obesity (BMI 25-39.9 kg/m2) but otherwise healthy, received baseline measurements and weight loss counseling. They visited the clinic daily to receive in random order either EB or CB each for one week. The two breakfasts were similar in energy density and macronutrients but differed in protein quality (mainly egg protein vs wheat protein). On days 7 and 14, satiety questionnaires using visual analog scales (VAS) were offered at 7 time points (-30, 30, 60, 90, 120, 180, and 240min), before and after the breakfasts. An ad libitum lunch was offered on days 7 and 14 and the energy intake was covertly recorded.
Results : Area under the curve (AUC) of each factor were compared between 2 breakfasts using a linear mixed effects model, adjusting for subject and visit. EB showed significantly more fullness (p=0.038). The differences between the AUCs between two breakfasts for hunger, thirst, nausea, and the amount that could be further eaten were not significantly different. There was no significant difference in LTEI between EB and CB. There was no evidence of carry-over effects.
A synthesis of the 3 studies indicates that when an EB is superior in protein quality and quantity, it can increase fullness and reduce LTEI. When the EB is higher in protein quality, but matched for protein quantity, it still increases fullness, but does not reduce LTEI. This insight could help in developing a weight loss diet plan, when increasing fullness and reducing energy intake are important considerations.
Funding Sources : American Egg Board / Egg Nutrition Center