What economic changes occurred during the middle ages?

The industrial revolution started in Britain. This caused the British to require more land and raw material to expand their industry, which in turn caused them to colonize lands like Malaya (for wood and mining areas), Singapore (as a prosperous port) and India (for spices like pepper, paprika, etc.). 

The impact on the British was that they had more food due to excess production in factories and there were more job opportunities for their people. The impact on the colonized people was that more and more immigrants were brought in the country creating diversity in places like Malaya and Singapore.