Does eating breakfast every day help prevent ADHD symptoms from developing?

No, breakfast habits aren't a proven prevention strategy for ADHD, though skipping breakfast can affect a child's energy and mood over the course of a morning. ADHD's strong genetic basis, with heritability estimates around 74 to 88% from twin studies, means daily nutrition timing isn't in the category of established causes or preventive factors. What's true is that low blood sugar from a skipped meal can produce irritability and poor concentration that might look ADHD-like in the short term, which is a reasonable thing to rule out, but that's different from breakfast meaningfully changing the odds of developing the underlying condition. References: https://doi.org/10.1038/s41380-018-0070-0