If I compile the following code, I get a slide where the normal block body text size is tiny as written in the code, while the body text size of example and alert block doesn't change.
I've also tried other combinations of \setbeamerfont
, but none of them are able to change the body text size of example and alert blocks.
\documentclass[aspectratio=169]{beamer}
\usetheme{Frankfurt}
\setbeamerfont{block title}{size=\Huge}
\setbeamerfont{block body}{size=\tiny}
\setbeamerfont{block title example}{size=\Huge}
\setbeamerfont{block body example}{size=\tiny}
\begin{document}
\begin{frame}
\begin{exampleblock}{Title}
Test
\end{exampleblock}
\begin{alertblock}{Title}
Test
\end{alertblock}
\begin{block}{Title}
Test
\begin{itemize}
\item Item
\end{itemize}
\end{block}
\end{frame}
\end{document}
Best Answer
With template
block body alerted
you will change example and alerted block body fonts. According to the manualblock body example
should be used to fix example body font, but with Frankfurt theme it didn't work.