Since his teens, Professor Lord John Krebs has been quietly and determinedly digging his heels in. When it came to applying to university, it was assumed he would be studying medicine.
His father, Hans Krebs, a ground-breaking physiologist, had won the Nobel Prize for Medicine in 1953 and worked at the Radcliffe Infirmary for many years.
And his grandfather, Georg, was an eminent surgeon in his native Germany.
But halfway through his interview at Trinity College, Oxford, where his father was a Fellow, he blurted out that he didn’t really want to study medicine.
He chose zoology instead and later, as professor of that subject at Oxford University, studied animal behaviour and won international recognition for his research into how birds remember where they hide their seeds.
In 2001, just one year into his five years as chairman of the newly formed Food Standards Agency, he banged heads with Government officials over the foot-and-mouth outbreak that year.
They had initially dismissed it as a minor issue that would resolve fairly quickly and it was his scientific approach in bringing together a group of eminent scientists to create complicated disease-modelling projections, that made central government sit up and take notice.
Although he was proved right, he left a few ruffled political feathers in his wake.
Two years later, he caused a media frenzy by saying organic food was no better for us than that grown on conventional farms.
The comments, made on television’s Countryfile programme in 2003, infuriated the organic lobby, including the Soil Association.
He further enraged them by refusing to condemn genetically modified food.
And for several years, the principal of Jesus College has been embroiled in an ongoing spat with the farming union and others who are angry that he does not support the widespread culling of badgers to control the spread of TB in cattle.
His newly-published book Food, A Very Short Introduction is a look at the brief history of human food and tackles big issues such as obesity, sustainability in farming and GM.
The catalyst was a series of talks he gave at the Royal Institution’s Christmas lectures.
“When I worked at the FSA, I learned a lot about the food industry and how it works and what goes into the food we buy in the shops,” he said.
“I wanted to get down on paper those topics including food safety and how we are going to feed the world in 2050 when there are nine billion people on the planet.”
The 67-year-old remains unrepentant about the organic row, pointing out that those who protested had vested interests.
“The thing I was particularly criticised for, was the assertion the Food Standards Association made that organic food is no better for you than ordinary food.
“That doesn’t play well with people like the Soil Association.
“They don’t want to be told their premium products they are charging a lot more do not actually do any good.
“But that wasn’t me saying it, it was scientific advice.
“You stick with the message bit absolutely straight, even if it means a loss of popularity.”
He believes it is easy to lose sight of the fact that for the vast majority of people, the issue of organic versus non-organic and where food comes from is not a huge priority and they may not be able to afford to make that choice.
He said: “People are pragmatic about the food they eat.
“Consumer surveys consistently show the biggest concern is price, convenience and time.
“Convenience is important and they want to save time when they cook.
“If you prompt people and ask if they are worried, they may say ‘yes’ but it will not be the first thing they say.”
His appointment as head of the FSA wasn’t popular with everyone.
There were accusations that, as an outsider, he did not understand the mechanics of the food industry.
A column in Private Eye sniped that his appointment had been made because he had no baggage, but, then, neither did a four-year-old child.
The organic comments drew more vitriol. One comment he received, he laughed, was that “Sir John Krebs ought to be juiced”.
He deals with the flak that has come his way with logic.
“You have to do two things,” he said. “Firstly, separate out your personal life from your professional life, so when people were very critical of me in the media, they weren’t criticising me they were criticising my public role.
“You have to harden yourself and not take it too literally. It’s about toughening up, to some extent.”
His great love when growing up at the family home in Iffley village was birdwatching and he still finds time to visit the RSPB bird sanctuary at Otmoor whenever he can.
His schooldays at what was City of Oxford High School in George Street were punctuated by family holidays which included walks with his father, who would talk about plants and natural history.
Home life is split between the terraced house in Jericho he shares with his wife Sarah Phibbs, an IT manager at the Museum of Natural History and lodgings provided by Jesus College.
He thoroughly enjoys his role as a cross-bench peer in the House of Lords.
As chairman of the Science and Technology Select Committee, he can question and hold to account minsters or civil servants.
He pointed out: “It’s a good way of bringing the scientific community to the fore and challenging strategy, which is incredibly important for us all.”