Three diets - Mediterranean, low-fat and low-carbohydrate - are equally effective in helping reverse blocked arteries, say Israeli researchers.
The study of 140 people, reported in the journal Circulation, found diet could reduce the fatty build up in arteries.
The Ben-Gurion University team found that by the end of the two-year study, the arterial wall had been cut by 5%.
Experts said the study was interesting, but diet was not a "magic bullet".
Atherosclerosis is a progressive condition in which the arteries thicken with fatty deposits, increasing the risk of heart attacks and strokes.
The authors of this Israeli study, which was carried out in collaboration with researchers in the US, Canada and Germany, set out to see if this natural part of ageing can be reversed through diet.
Volunteers followed one of three diets - a low-fat diet, a low-carbohydrate diet or a Mediterranean diet, which is based on eating lots of fruit and vegetables, and using olive oil as the main source of fat.
They were asked to stick to the diet for two years, and record what they ate in food diaries.
The study was carried out among overweight volunteers, mostly men, who were aged 40 to 65.
Using three-dimensional imaging, the researchers measured the volume of the wall of the carotid artery, the large artery in the neck which takes blood up to the brain. This was done at the start of the study and again after two years.
Lead researcher Iris Shai said: "It was very interesting to see that these very different diets had a similar effect.
"Some people suggest that low-carbohydrate diets are more likely to clog arteries, but we did not see that."
The research paper suggested the link could be related to falling blood pressure caused by the change in diet.
The findings were welcomed by UK experts.
Dr Charles Knight, secretary of the British Cardiovascular Society and a consultant cardiologist, said although the study was "relatively small" and was not able to follow through to find out how many people eventually had heart attacks or strokes, the results were nevertheless "very interesting".
He pointed out that the study adds weight to the growing body of research that suggests that atherosclerosis is a modifiable disease.
Ten to 15 years ago, it was thought that fatty build-up in the arteries was irreversible, but since then drugs trials have shown that it is possible for fatty deposits to be cut.
"This study shows you can do something to reduce plaque build-up, even without pills," Dr Knight said.
"It sends an effective message from a public health perspective."
However, he warned that the scale of reduction in the volume of artery walls was relatively small and that changing diet, although helpful, was "no magic bullet".