Beamer and description environment text size

Question

Is it possible to define a the description environment size like it its possible with itemize and enumerate?

\setbeamerfont{itemize/enumerate body}{size=\small}
\setbeamerfont{itemize/enumerate subbody}{size=\footnotesize}
\setbeamerfont{itemize/enumerate subsubbody}{size=\scriptsize}

I have been using:

\begingroup
\small
\begin{description}
\item[aaa] bbb
\item[ccc] ddd
\end{description}
\endgroup

But I don't know if it is the better approach. Also, sometimes I prefer to use the following construction:

\begingroup
\small
...
\endgroup

For text, figures, tables or even itemize/enumerate to fit the contents in a frame, instead of using the shrink option:

\begin{frame}[shrink]{Frame title}
...
\end{frame}

Which I also don't know the better approach.

Answer 1

There's the description item template/font/color, but this only affects the labels in the description environment. To change the font size for the labels and the text, you can use the etoolbox package to patch description:

\documentclass{beamer}
\usepackage{etoolbox}

\AtBeginEnvironment{description}{\small}

\begin{document}

\begin{frame}

\begin{description}
\item[aaa] bbb
\item[ccc] ddd
\end{description}

\end{frame}

\end{document}

The shrink option is evil (see the beamer documentation). I would suggest you, however, to use a consistent font size and not to reduce it for just parts of your presentation (it introduces inconsistency and reduces the beauty of your presentation); try instead to redesign your frames (if possible) so as to contain less text.