I tried \resizebox{\textheight}{!}{} but not adjusting the content to the page height in the frame.
I do it manually by \small{...}, \footnotesize{...} and \tiny{...} but it is too cumbersome.
Example slide
\documentclass{beamer}
\usetheme{Berkeley}
% http://tex.stackexchange.com/a/94632/13173
\newenvironment{slide}[1]
{\begin{frame}[environment=slide,allowframebreaks,fragile]
\frametitle{\insertsection-#1}
}
{\end{frame}}
\begin{document}
\section{Introduction}
\begin{slide}{Global burden by World Bank}
\tiny{
Global burden of STIs and their consequences (World Bank)
\begin{itemize}
\item among world’s most common diseases, with an annual incidence exceeded only by diarrheal diseases, malaria, and lower respiratory diseases.
\item Due to their high \textbf{prevalence}, particularly in developing settings, STIs result in substantial productivity losses for individuals and communities. %, particularly where the majority of the population is under 40 years of age.
\item In developing countries, STIs are among the leading causes of disability-adjusted life years (DALYs) lost for \textbf{women} of reproductive age.
\item Every day, 1M \textbf{acquire} a new STI, and more than 340 million new cases of curable STIs occur throughout the world each year.
Adolescents and young adults have the highest rates of curable STIs -- up to 1 in 20 adolescents develop a new STI each year.
\item \textbf{Untreated} bacterial STIs in women - PID in 40\% infections, 1/3 in infertility, ...
\item \textbf{Perinatal deaths}. Syphilis - one of most common causes of adverse pregnancy outcomes globally, 1.5M deaths/year.
\item \textbf{Chronic liver disease and death}. HBV, 1/40 deaths of adults globally per year.
\item \textbf{Cervical cancer and death}. Most common cause of cancer mortality among African women. About 0.24 M/year mortality in resource poor seettings.
\item \textbf{Prevention}. Vaccines, .... Antibiotics for many STIs. Antivirals in HIV and HSV-2.
\end{itemize}
}
\end{document}
Output which is not adjusted to the page size
OS: Debian 8.5


\tiny{...}– David Carlisle Jan 01 '17 at 14:09allowframebreakswhich allows text to run over to the next slide if you want to force it all on to one slide?????? – David Carlisle Jan 01 '17 at 14:13\smallis definitely the best thing to do here, I can't see it as being "cumbersome" at all, surely in the overall work of preparing a presentation choosing the font size for one slide is negligable. – David Carlisle Jan 01 '17 at 14:24