"Finding out more about why children like and dislike foods is important in helping us understand the problems of obesity. Childhood obesity can lead to a number of health problems in later life including cancer," explained study leader, Professor Jane Wardle, from Cancer Research UK's health behaviour unit.

Children's obesity has gained significant attention in the health care and child welfare arenas over the past five years. Worldwide over 22 million children under five are severely overweight.

The study, a collaboration between University College and Kings College London, evaluated taste preferences of 103 pairs of identical twins and 111 pairs of non-identical twins (aged four to five) by asking their mothers to complete 77-food item food frequency questionnaires.

Identical twins share all their genes, while non-identical twins share about 50 per cent of their genes, giving the researchers the opportunity to investigate genetic and environmental factors on food preference.

The researchers, grouping foods as 'vegetables', 'fruits', 'desserts', and 'meat and fish', found that heritability for protein-rich meat and fish was high, with a calculated additive genetic effect of 0.78, compared to the low heritability of desserts (0.2) and vegetables (0.37).

"The finding of higher heritability for protein foods is novel, but this is the first study to have included significant numbers of protein foods," wrote Wardle.

Conversely, environmental factors appeared to greatly influence preference for desserts and vegetables (0.51, 0.64), but not for meat and fish (0.12).

"It is not clear exactly what environmental factors are influential when it comes to fruit, vegetables or puddings," said Wardle.

"It might be that children who witness their parents show enthusiasm or distaste for certain types of vegetables or puddings are likely to follow suit. Or it might be that if a particular food is always available children learn to like it. For instance if a fruit bowl is always full of bananas children might think of them as being a favourite food," she said.

The researchers said that, although the study suggested that food preferences had a heritable component, the study did not show what exactly was inherited.

"One possibility is that PROP and PTC [bitter and sweet] sensitivity play a small part, along with many other as yet undiscovered taste receptor differences," they said.

Dr Lesley Walker, director of cancer information at Cancer Research UK, welcomed the study, saying it was important: "It adds to our knowledge of understanding very young children's food preferences. The more we know about this the better we can understand what leads to bad eating habits which brings with them a whole range of health problems."