In her book "Gulp: Adventures on the Alimentary Canal," author Mary Roach discusses the phenomenon where individuals who assert they are lactose intolerant often also believe they are gluten intolerant. This raises questions about the validity of these claims, as many of these individuals lack concrete evidence to support their assertions regarding either intolerance.

This observation implies a potential trend where some people may self-diagnose dietary sensitivities without medical confirmation. Roach's insights suggest a broader conversation about food intolerances and the importance of proper diagnostic processes in understanding our dietary needs.