Experts say a healthy diet should include 10 portions of fruit and vegetables a day, double that of New Zealand's 5+ A Day campaign.
The advice comes after a 12-year University College London study which found that people who ate at least seven portions of fruit and vegetables each day were 42 per cent less likely to die from any cause over the course of the study.
Lead author Dr Oyinlola Oyebode of UCL's department of epidemiology and public health said: "The clear message here is that the more fruit and vegetables you eat, the less likely you are to die at any age. My advice would be, however much you are eating now, eat more."
Professor Simon Capewell, of the department of public health at the University of Liverpool, said the advice should be 10 portions a day. "Humans are designed to be omnivorous: a handful of nuts, seeds, fruit and the occasional antelope. We're not meant to be eating junk food."
Researchers examined the eating habits of 65,000 people in England between 2001 and 2013.
The 5+ A Day message encourages people to eat five or more servings of fresh fruit and vegetables every day to lower the risk of heart disease, stroke, type-two diabetes and obesity.
Only 30 per cent of people managed to eat that amount, according to the study. New Zealand's own 5+ A Day campaign was founded in 1994 by non-profit organisation United Fresh NZ.
General manager of 5+ A Day Paula Dudley said: "We are aware that eating more than five servings of fruit and vegetables a day is best. This is why we advocate 5+ A Day, five servings being the starting point that people need to build on ... What this study reinforces is the positive effects eating more fruit and vegetables has on our health and wellbeing, the more the merrier, especially when it come to vegetables."
The study showed that people who ate between five and seven portions a day had a 36 per cent reduced risk of death, those who ate three to five portions had a 29 per cent decreased risk and those who ate one to three helpings had a 14 per cent reduced risk. Those with the highest intakes were also 25 per cent less likely to die from cancer and 31 per cent less likely to die from heart disease during the course of the study.
The research also found that vegetables were four times healthier than fruit and that fruit juice was found to have no significant benefit.
Last month, research published in the New Zealand Medical Journal showed a 20 per cent tax on sugary soft drinks would prevent 67 deaths from cardiovascular disease, diabetes, and diet-related cancers a year.
*12-year University College London study on the effects of fruit and vegetables
*People who ate at least seven portions of fruit and vegetables each day were 42% less likely to die from any cause over the 12 years
*People who ate between five and seven portions were 36% less likely to die
*Those with the highest intakes were 25 per cent less likely to die from cancer and 31 per cent less likely to die from heart disease
- additional reporting Daily Telegraph UK