Summary There is growing evidence that people who eat breakfast regularly tend to be slimmer than those who skip breakfast. However, this is not a consistent finding and it is not true for all types of breakfast. Also the relationship with breakfast can disappear in studies when adjusted for breakfast cereal consumption, suggesting it is breakfast cereal that is driving the association. This systematic review, therefore, looked specifically at the relationship between breakfast cereal consumption and weight.
A systematic search of the literature identified nine references looking at the relationship between the consumption of breakfast cereals and BMI as an outcome measure.
Five of the nine included studies were in adults. These studies consistently showed that people who eat breakfast cereals regularly tend to have a lower BMI and are less likely to be overweight than those who do not eat breakfast cereals regularly. Although not all of the results were statistically significant, they all point in the same direction. There was no evidence that regular breakfast cereal consumers have lower daily energy intakes than infrequent consumers.
Four of the nine included studies were in children. As for adults, the evidence from the included studies is consistent that children who eat breakfast cereals regularly tend to have a lower BMI and are less likely to be overweight than those who eat breakfast cereals infrequently. There was no evidence that children who consume breakfast cereals regularly have lower energy intakes than infrequent cereal consumers.
This systematic review considered whether the relationship between breakfast cereal consumption and weight is likely to be mediated either through lower energy intakes or higher energy expenditures. We found no clear evidence for this or for any other proposed mechanism. The relationship could arise out of confounding by lifestyle factors.
There is consistent evidence of an association between breakfast cereal consumption and a healthy weight, but limited evidence for any proposed mechanism that would point to it being a causal relationship.