Experts have warned that non-dairy or wheat free fad diets could be putting young women at risk of developing osteoporosis in later life.
Research has shown that nearly a third of women are so keen to shed those extra kilos that they are cutting out entire food groups.
Failure to build strong bones by the age of 35 raises the risk of osteoporosis in later life.
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 slim for summer.
Some 28 per cent of these said they give up cheese and, for 11 per cent, all dairy products are taken off the menu.
More than four in ten (41 per cent) cut out bread, which is a major source of calcium.
More than a quarter of those surveyed (26 per cent) said they only pay attention to the fat and calorie content of food labels, ignoring all the other information about their nutritional content.
"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," the Telegraph quoted a spokesman for the National Osteoporosis Society as saying.
"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," he added.
Supplement firm Ellactiva conducted the survey.