Irwin Simon, the founder, president and CEO of Hain Celestial, often comes across as one of the more forthright chief executives in the US food industry, with a firm belief in his company and its prospects. With Hain Celestial's domestic business facing challenges and investor scrutiny intensifying, Simon this week set out how the company will improve its performance in the US and why he believes the group can thrive amid increasing competition - but there were signs he acknowledges the need to adapt to meet the challenge.