The effect of whole egg consumption on weight and body composition in adults: a systematic review and meta-analysis of clinical trials

BACKGROUND: A limited number of studies have directly examined the effect of whole eggs on body weight and composition in adults, and they have led to inconsistent results. This study aimed to summarize the evidence on the effect of whole egg consumption on body weight and body composition in adults from clinical trials. METHODS: Online databases were searched from inception to April 2023 for clinical trials that directly or indirectly assessed the effect of whole eggs consumption on anthropometric measures including body weight, body mass index (BMI), waist circumference (WC), and fat-free mass (FFM) in adults. A random effects model was used for meta-analysis. RESULTS: In total, 32 controlled clinical trials were included in the systematic review. The analyses revealed that whole egg consumption has no significant effect on body weight (n = 22), BMI (n = 13), WC (n = 10), and FFM (n = 4, P > 0.05). The subgroup analyses showed that whole egg consumption has an increasing effect on body weight and BMI in studies that lasted more than 12 weeks and in unhealthy participants (P < 0.05). A significant increasing effect on BMI was found in studies that the control group did not receive any egg (P < 0.05). Moreover, in studies that there was no significant difference in energy intake between the intervention and control groups, weight, and WC were significantly increased (P < 0.05). Additionally, in studies that participants in the control group received another food or supplement, studies with calorie restriction, and studies on healthy subjects, whole egg intake significantly decreased BMI (P < 0.05). CONCLUSIONS: Although whole egg consumption had no adverse effect on body composition and body weight, in overall, it might increase body weight in long term. Egg consumption beneficially affects BMI in healthy people and during weight loss diet. SYSTEMATIC REVIEW REGISTRATION: This systematic review and meta-analysis is registered in the International Prospective Register of Systematic Reviews (PROSPERO, Registration number: CRD42022308045). SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1186/s13643-023-02277-3.