A study has shown that nearly a third of women are so desperate to lose weight that they are cutting out entire food groups, some of which are rich sources of bone-strengthening calcium, “The Daily Telegraph” reported.

In fact, the study, based on a poll of the eating habits of 4,500 British women, found that 30 per cent admitted to avoiding entire types of food when trying to stay slim.

Some 28 per cent of the respondents said they give up cheese and, for 11 per cent, all dairy products are taken off the menu. More than four in 10 (41 per cent) cut out bread, which, by law, is fortified with calcium.

More than a quarter of those surveyed (26 per cent) by supplement firm ellactiva said they only look at the fat and calorie content of food labels, ignoring all other information about their nutritional content, the poll found.

Failure to build strong bones by the age of 35 raises the risk of osteoporosis in later life, say the experts. The Food Standard Agency says adults should be able to get the 700 mg of calcium a day they need from a varied or balanced diet.

A spokesman for the National Osteoporosis Society said: “This latest research highlights the worrying implications that body image can have on bone health. Both calcium and fat play a role in building bone so fad diets that cut these out completely can be damaging.

“There’s a lot of pressure to be slim, but by trying to stay too thin, bone health can be compromised. Low fat dairy products are available and many actually contain more calcium that the full fat varieties. For example, skimmed milk has more calcium than full fat.”