Kentucky Fried Chicken has had to cut healthier options from its menus after "no-one" bought them.
According to one senior executive at KFC, the chain tried three times in the last decade to introduce menu items that were less calorific.
The colonel even spent £8 million pounds installing ovens into its outlets in the UK, the Daily Mail reported.
And an attempt to make the chips less fatty has caused the fried chicken giant "a lot of grief", Jenny Packwood, head of brand engagement at KFC UK and Ireland, said.
Speaking about the problems at the Public Health England annual conference in Warwick, she said attempts to sell items like grilled chicken sandwiches and pulled chicken had failed.
Ms Packwood said: “It didn't go brilliantly well. We tried and we failed to launch a non-fried product.
“It's no good launching a product which looks good nutritionally but then nobody buys.
“It doesn't improve the health of the nation and in terms of sustainability it is a disaster.”
KFC has tried to reduce the calories in its chips by making the french fries thicker so they absorb less oil and fewer calories. But this has lead to complaints from customers.
Ms Packwood added: “Frankly it has been controversial and we get a lot of grief about our fries.”
Dr Alison Tedstone, chief nutritionist at Public Health England, has urged companies to keep changing their menus to be healthier.
PHE has plans to introduce voluntary calorie caps for restaurants and supermarkets to fight obesity.
Dr Tedstone said: “A small change in chips could have a massive effect.
"The heart of this project is changing the ‘everyday’ product.
"You get to the bog standard person who is coming in to buy chips, rather than the health-seeker, who may be doing something different."
