In anÂ editorialÂ in the British Journal of Sports Medicine, three international experts said it was time to â€˜bust the mythâ€™ 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 celebratory 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.
But despite this public health messaging had “unhelpfully” focused on maintaining a healthy weight through calorie counting when it was the source of calories that mattered most – research has shown that diabetes increases 11-fold for every 150 additional sugar calories consumed compared to fat calories.
And they pointed to evidence from the Lancet global burden of disease programme which shows that unhealthy eating was linked to more ill health than physical activity, alcohol and smoking combined.