Activist investor Nelson Peltz laid down the gauntlet when his investment vehicle, Trian Fund Management, issued a call for PepsiCo to merge with Mondelez International and then split its drinks and snacks businesses. While a number of hurdles stand in the way - not least apparent opposition from management - it is clear the pressure to perform has been turned up a notch or two as PepsiCo prepares to issue its half-year results tomorrow (24 July). Katy Askew reports.