Breakfast is the most important meal
Large observational studies associate regular breakfast consumption with lower BMI, improved glucose metabolism, and better cognitive performance in children. However, randomized trials have challenged breakfast's unique importance, and the relationship may reflect confounding by overall healthy lifestyle habits.
What we know
The idea that breakfast is the most important meal of the day has nutritional support in some domains but has been challenged by recent research. Observational studies, including analyses of tens of thousands of participants, have found that breakfast skippers tend to have higher BMI, greater risk of type 2 diabetes, and poorer dietary quality overall. Large prospective studies including the Nurses' Health Study have linked breakfast skipping to increased diabetes risk.
For children, evidence is stronger: multiple reviews show associations between eating breakfast and improved cognitive performance, particularly attention and memory, and lower obesity risk, though many studies have methodological limitations. The effect appears most pronounced in undernourished children.
However, a 2014 randomized trial published in the American Journal of Clinical Nutrition found that in adults trying to lose weight, being assigned to eat or skip breakfast made no significant difference in weight loss, challenging the assumption that breakfast skipping specifically causes weight gain. The 2018 International Breakfast Research Initiative review concluded that breakfast's health effects are real but complex and depend on factors including meal composition, total daily intake, and individual health status.
Intermittent fasting protocols, which typically skip breakfast, have shown benefits in some clinical trials, further complicating the picture. The current scientific consensus is that breakfast has genuine but context-dependent benefits, and that calling it 'the most important' meal overstates the evidence.
Common claims
- Skipping breakfast slows metabolism permanentlyNot supported by RCT evidence
- Breakfast is essential for healthy weight managementEvidence is mixed; context-dependent
- Breakfast improves children's school performanceSupported, especially in undernourished children
- Everyone should eat breakfast daily for optimal healthRecommendation depends on individual factors