Choc therapy: Nestle Rowntree marketing manager Andrew Harrison is no stranger to the charms of his products, nor to the tastes and habits of his customers. Michael Bird joins him for a mid-afternoon snack and a spot of sweet talking.(Profile: Andrew Harrison, Nestle Rowntree)

"This is a classic Rolo occasion," says Nestle Rowntree marketing director Andrew Harrison. It's 4pm in the company's HQ and factory in York as he leans back in his chair, toys with a packet of the chocolates, teases one out and pops it into his mouth.

"We all sit around a table, nibbling a bit, and then when the chew is over we each take two or three more. You wouldn't have a Rolo at 9am, and you wouldn't have one at 9pm either," he explains.

Harrison prizes his knowledge of the need state of his consumer at different times of the day--and his ability to match a piece of confectionery to that impulse. "There's very little consumption of After Eights early in the morning," he says. "Mint is too strong a flavour so early in the day."

Harrison, who turns 39 this year, worked in the marketing departments of Proctor & Gamble and Coca-Cola before switching his expertise in sweet-tasting FMCGs to Nestle Rowntree three years ago. Now he has an ongoing desire to know what drives people to eat chocolate, and how marketing can use this to make consumers buy more Nestle products.

Eating habits in the UK have changed in the past few years and chocolate has become more of a …