For millions who greet each morning with a cup of coffee, a new study quietly complicates that ritual — suggesting that habitual caffeine consumption may gradually work against the body's ability to maintain strong bones. Researchers have added fresh evidence to a long-standing scientific debate about how caffeine interferes with calcium absorption, raising questions not about whether to drink coffee, but about how to drink it wisely. The finding is less a warning than an invitation to see our daily habits within the fuller context of how we nourish ourselves over a lifetime.