The Relationship of Ready-to-Eat Cereal Intake and Body Weight in Adults: A Systematic Review of Observational Studies and Controlled Trials

Results from observational studies indicate that consumption of ready-to-eat cereal (RTEC) is associated with higher diet quality and lower incidence of overweight and obesity in adults compared with other breakfasts or skipping breakfast. However, randomized controlled trials (RCTs) have had inconsistent results regarding effects of RTEC consumption on body weight and composition. This systematic review aimed to evaluate the effect of RTEC intake on body weight outcomes in observational studies and RCTs in adults. A search of PubMed and Cochrane Central Register of Controlled Trials (CENTRAL) databases yielded 28 relevant studies, including 14 observational studies and 14 RCTs. Results from observational studies demonstrate that frequent RTEC consumers (usually ≥4 servings/wk) have lower BMI, lower prevalence of overweight/obesity, less weight gain over time, and less anthropometric evidence of abdominal adiposity compared with nonconsumers, or less frequent consumers. RCT results suggest that RTEC may be used as a meal or snack replacement as part of a hypocaloric diet, but this approach is not superior to other options for those attempting to achieve an energy deficit. In addition, RTEC consumption was not associated with significantly less loss of body weight, or with weight gain, in any of the RCTs. RTEC intake is associated with favorable body weight outcomes in adults in observational studies. RTEC does not hinder weight loss when used as a meal or snack replacement within a hypocaloric diet. Additional long-term RCTs (≥6 mo) in both hypocaloric and ad libitum conditions are recommended to evaluate further the potential effects of RTEC consumption on body weight outcomes. PROSPERO (CRD42022311805).