Just go out and get more exercise. Wrong, wrong, wrong.
I’m especially vigorous about denouncing this myth because I was a perpetrator. I didn’t understand that when I was young I was one of those lucky people who could eat more carbohydrates (sugar), yet still be very active. Turns out that high sugar diets suppress activity levels for most people. If you force yourself to exercise a lot, yet continue to eat high sugar diets, you’ll probably gain weight, not lose it. The 12 year old girl featured in Fed Up comes to mind. She exercised like a fiend and got heavier. Likewise, William Banting recounts his countless hours of rowing while he gained more weight. Fed Up does a good job of making that point that food and beverage companies are all too willing to promote exercise. I suspect drug companies may have similar tendencies. It’s a great cop-out so they don’t have to take responsibility for providing toxic nutrition or for treating symptoms with drugs instead of causes with diet.
In April 2015 in the British Journal of Sports Medicine, Aseem Malhorta, Tim Noakes, and Steve Phinney spelled this out pretty bluntly in their editorial “It is time to bust the myth of physical inactivity and obesity: you cannot outrun a bad diet.” They pretty directly accuse the food industry of the same sort of misdirection that the tobacco industry was notorious for.
The best way to get your body to work well is to combine good diet with good exercise. But without the good diet, you’ll be disappointed by the effects of exercise unless you’re one of those genetically lucky few. And even then, you may suffer health effects over the long term, like the runners I know who came down with early onset Alzheimer’s disease.