People can shape up by visiting their local fast-food outlet

Devotees of Pizza Hut, Taco Bell and Kentucky Fried Chicken are to be offered free gym membership in January.

Parent company Yum Brands says anyone visiting these outlets next month will get a four week health club membership.

Fast-food operators have been under pressure to repel the charge that they are feeding an obesity epidemic.

They have responded by offering a wider choice of options for the health-conscious.

McDonald's has enjoyed success with a range of salads while KFC has been supplying less fatty, roasted chicken.

Many fast-food companies have seen their profits ground down in recent years as more people have turned to less fatty more protein rich diets.

Yum operates 18,000 restaurants in the United States.