The Food Standards Agency is on a collision course with manufacturers over its proposals to cut fat and sugar consumption by reformulating grocery lines.

The Food and Drink Federation has warned the FSA that a cross-category programme of fat and sugar reduction similar to that seen for salt two years ago could backfire and harm people's health.

Such an approach would put the well-being of the elderly and those who had lost weight through illness at risk, said the FDF.

The comments came in the FDF's response to the FSA's draft saturated fat and energy intake programme, in which the agency advocates reformulation.

Reformulation could meet resistance from consumers who increasingly sought 'clean' ingredients, the FDF added.

"Making reduced-calorie or lower-fat versions of foods often requires technical interventions, such as using more sweeteners, preservatives, colloids and/or emulsifiers," it said. "But consumer research shows many consumers like to buy foods made with 'conventional' or 'natural' ingredients. Introducing more processing or additives may not have the desired effect of moving consumers towards 'reduced' options."

It also complained of a lack of incentives for manufacturers to cut sugar and fat levels. "The operation of the FSA's Nutrient Profiling Model means many reformulated products would still be subject to advertising restrictions.

"Similarly the FSA principles for signpost labelling schemes mean reformulated foods may carry the same 'traffic light' colour."

In the week a diabetes charity claimed thousands of young women were skipping insulin injections to lose weight, the FDF also warned that by targeting its efforts at the whole population, the FSA threatened to trigger increased rates of eating disorders in teenage girls.

The FSA should instead put the spotlight on those most in need of help, primarily the obese and those with high cholesterol levels, it said. "An energy reduction strategy should be focused only on those in positive energy balance, and not on the whole population, as it will not be appropriate for all."