Contrary to popular opinion, adults do eat more healthily than they did as children.
Some adults think they do not have time to prepare a healthy meal
Newcastle University researchers looked at the diets of 200 children aged 11 and 12, then again 20 years later.
They found as adults, they ate around twice the amount of fruit and vegetables and less fat and sugar as they had as children.
But the study, in Appetite, found some saw barriers, such as a perceived lack of time, to healthy eating.
This group often believed fruit and vegetables needed time for preparation and cooking and were more likely to have smaller intakes in fruit and vegetables.
'Messages getting through'
In addition to perceptions of the time available to prepare food, participants said parents, partners and children could affect their attitudes to their diet.
So those who saw their parents' influence as positive consumed more fruit and vegetables as adolescents.
Whether partners were seen as positive or negative depended largely on gender.
A third of people - mainly men - felt their partners had a positive influence on their diet, 10% - mainly women - said their partners' influence was negative.
Amelia Lake, a registered dietician and Newcastle University researcher, who led the research said the findings suggested that general healthy eating messages - such as the five a day message on fruit and vegetables - were getting through to most people,
She added: "Work from this study has shown that children who were high fruit and vegetable consumers maintain this intake into their early thirties.
"This reaffirms the importance of the National Fruit in Schools Scheme, where children are being encouraged to eat fruit.
"We also need to examine the availability of healthy food in venues such the workplace and in shops. Despite all the healthy eating messages that abound, it's still easier to go to a local shop and buy a chocolate bar rather than a piece of fruit."
But she said they also needed to be more carefully targeted to reach individuals who believe their lifestyle still prevents them from eating well.
"A lot depends on people's individual coping mechanisms and attitude to life.
"A lack of time is not necessarily the reason for people not attempting to eat healthily.
"Some working adults are inspired to make a healthy meal in the evenings, while somebody with the same amount of time on their hands would feel under pressure and be inclined to send out for a takeaway."
Ms Lake added: "These results suggest that the diet is really up to the individual and their personality, and that general health messages are not necessarily enough when a variety of factors are working to prevent people from eating healthily."