Eating seven or more portions of fruit and vegetables a day is healthier than the five currently recommended and would save more lives, researchers say.
The University College London study of 65,000 men and women indicated the more fruit and vegetables people ate, the less likely they were to die - at any age.
It indicated "seven a day" cut death risk by 42 percent; "five a day" by 29 percent.
Critics say other factors such as not smoking or drinking excessively may have accounted for the drop, although the study authors say they tried to account for this, the BBC reports.
The British government says its "five-a-day" advice is sufficient and many people struggle to achieve even this.