\begin{tabular}{@{}crr@{}}
\toprule
                &\multicolumn{2}{c}{\textbf{Amount (\%) of a starter}}\\
                          \cmidrule(rl){2-3}
\thead{°C / °F} & \thead{Recently fed} & \thead{Starving}\\ \midrule
       30 / 86  &  5 &  2.5 \\ 
       25 / 77  & 10 &  5   \\ 
       20 / 68  & 15 & 10   \\ \bottomrule
\end{tabular}