This free BMJ editorial was published back in 2015. However, personally I think public awareness is still poor and I would say many still believe in this myth.
“Instead, members of the public are drowned by an unhelpful message about maintaining a ‘healthy weight’ through calorie counting, and many still wrongly believe that obesity is entirely due to lack of exercise.”
Basically physical activity does not necessarily promote weigh loss, diet is crucial in combating obesity. On the other hand, maintaining a normal BMI does not preclude you from diabetes, hypertension, dyslipidaemia and many other conditions. That is the danger of a high sugar diet especially from junk food.
An interesting read indeed: