title: Loading/Reading data in R taking up too much memory
body: <p>I am using R for some data analysis. System specs: i5 + 4GB RAM. 
  For some reason, my R session is taking up a chunk of my RAM much much bigger than my data which leaves me with very little space for other operations.</p>
  
  <p>I read a <strong>550MB csv</strong> file, memory taken by <strong>R: 1.3 - 1.5GB</strong>
  I saved the csv as a .RData file. <strong>File size: 183MB</strong>. Loaded the file in R, memory taken by <strong>R: 780MB</strong>.
  Any idea why this could be happening and how to fix it?</p>
  
  <p>Edits: 
  The file has 123 columns and 1190387 rows. The variables are of type <code>num</code> and <code>int</code>. </p>