To boost your energy, drink a cup of tea. Tea contains L-theanine and caffeine, which in combination, can boost up alertness, memory and reaction time.

L-theanine and caffeine are also essential to reduce mental fatigue. A research conducted by University College London has suggested that drinking tea 4 times a day for a continuous period of 6 weeks would bring down the levels of cortisol, the hormone that gets released in high stress situations. The black varieties are specially noted as stress remedies.