When asked spontaneously, 63 per cent of the more than 2,000 adults polled by MORI said they had made some kind of change to theirs or their family's eating habits or activity levels in the past year.
The most common change was to eat more fruit and vegetables (30 per cent cited this change), and the figure was even higher among those with children under 15 (38 per cent).
A fifth said they had taken more exercise and 13 per cent said they were cutting down on fat or had switched to reduced fat products.
A further 10 per cent said they were eating less convenience food to improve their health, while 9 per cent claimed to be cutting down on salt, and 8 per cent were reducing overall food intake and snacking.
The research, commissioned by the National Consumer Council, a government-funded consumer body, was designed to assess to what extent consumers had been influenced by the government's white paper on health, launched this time last year.
While many of the proposals included in the paper have not yet been implemented, the media coverage surrounding the plans, and separate publicity for healthier eating generated by celebrity chefs and TV programmes appears to have triggered new efforts by the public.
Sue Dibb at the National Consumer Council said: "Whilst we are unable to say for sure what is influencing people, publicity for Jamie Oliver's 'Feed me better' and the Food Standards Agency's salt reduction campaigns have obviously encouraged changes in people's lifestyles."
More than 80 per cent of the participants said they were aware of a government campaign to tackle obesity and encourage healthy eating.
But Dibb added that those most at risk from a poor diet, particularly poorer families, need practical solutions from food companies and government to help continue this trend.
The survey shows that social class, gender and marital status all affect diet and lifestyle. Around four in 10 men, aged over 55, have made no changes to their lifestyles over the past year.
A similar proportion of low-income families and single people have also failed to change their habits.
More than half of those surveyed believe that healthier school meals is one of the most important ways of encouraging people to eat more healthily and 48 per cent said that a reduction in the amount of fat, salt, and sugar in processed foods would also help.
Many also wanted to see a greater choice of affordable, healthy foods in local shops.