Alpro dietician Kate Arthur said: "More and more dieters are realising that the fad diet promises of shedding huge amounts of weight in just a few weeks are either hollow, or that the diets are impossible to follow.
"The reality is that the majority of these diets are so impractical, and indeed so little fun that we often give up within just a few days."
Out of half of the respondents who regularly diet, Alpro found that two out of five dieters quit within the first seven days.
One out of five people are able to sustain it for a month, and the same number make it to the three-month mark, while the remainder stay dedicated for at least six months.
However, only one in 20 is likely to still be following their new healthy eating regime after one year.
