The agency, which is preparing to publish its strategy for reducing consumption of saturated fat and sugar, has written to industry bodies asking what steps their members have already taken to reduce fat and sugar levels in the products they make, and what further reductions they could achieve.
The agency said it would use their responses, due in next week, to inform a public consultation on strategies for reducing fat and sugar intake, which will be published later this year.
The FSA said it was too early to say what approach it would take, although there will be fears of a repeat of the lengthy battle over reformulation of products seen previously for salt.
Manufacturers will warn the FSA that it should not set targets for reducing saturated fat and sugar levels in food and drink unless public acceptance can be assured - and will point out that consumers already have a wide choice of lower fat and sugar products in most categories.
Alison Ward, director of communications at the Biscuit, Cake, Chocolate and Confectionery Association, said: "There's been a lot of innovation in terms of reduced fat products. But we have to be careful. In our sector people are quite clear about how they want products to taste."