Mr Shelford had also been involved with the New Zealand Prostate Cancer Foundation and became an ambassador for Jenny Craig in that time.
"I got so big I couldn't do up the old shoe laces. It was time to do something about it."
He said the book has been written in a simplified language, with help from Professor Grant Schofield, which means "everyone can read it".
But this was not Mr Shelford's first visit to the region.
He had played at the Memorial Park rugby ground in 1985 and 1986 before being selected to be an All Black.
"I think I scored a couple of tries on this ground," he said.
Mr Shelford will travel to Palmerston North today as part of the week-long book tour before heading to the South Island.
Sports broadcaster Keith Quinn was happy to interview Mr Shelford at the event because "nice people turn up and they're interested in what they have to say".
He said the interview was intended to be a "mix of Buck and his life in the public eye".
"All of his life is mixed with being a much-loved Kiwi who would never have a day in his life when somebody wouldn't come up and speak to him as though they felt like they knew him," he said.
The Wairarapa event was organised by the Wairarapa Sports Education Trust in association with Hedley's Booksellers and the Wairarapa District Health Board.