Physical activity has little role in tackling obesity - and instead public health messages should squarely focus on unhealthy eating, doctors say.
In an editorial in the British Journal of Sports Medicine, three international experts said it was time to "bust the myth" about exercise.
They said while activity was a key part of staving off diseases such as diabetes, heart disease and dementia, its impact on obesity was minimal. Instead excess sugar and carbohydrates were key.
The experts, including London cardiologist Dr Aseem Malhotra, blamed the food industry for encouraging the belief that exercise could counteract the impact of unhealthy eating.
They even likened their tactics as "chillingly similar" to those of Big Tobacco on smoking and said celebrity endorsements of sugary drinks and the association of junk food and sport must end.
They said there was evidence that up to 40% of those within a normal weight range will still harbour harmful metabolic abnormalities typically associated with obesity.
Dr Aseem Malhotra, Cardiologist said:
"An obese person does not need to do one iota of exercise to lose weight, they just need to eat less. My biggest concern is that the messaging that is coming to the public suggests you can eat what you like as long as you exercise."
"That is unscientific and wrong. You cannot outrun a bad diet."
Exercise 'not key to obesity fight', say scientists
Exercise does little to tackle obesity, according to a group of doctors and sports scientists writing in the British Journal of Sports Medicine