History why did the united states support the overthrow of an elected guatemalan president? answers

The United States overthrew the President of Guatemala so that they could protect various U.S. business interests. The ability to stop communism is also cited as he was promoting and was elected for some of the more communist policy changes that he wanted to make. Another threat of Communism so close to home could not be had. There were too many problems with Cuba. 

We have helped many rebellions to overthrow leaders that were not in line with US businesses or our political ideals. 

Land intrests
Initially the USA argued that the democratically elected leader was being very soft on the communist block and it seemed he was leaning toward it. The classified reports however shows private land owners interests were the driving motivation and not American desire to maintain control of the region.