He's not entirely wrong; losing weight, eating healthy, quitting smoking, drinking less alcohol or none at all . . . all of these things contribute to better health, but there are still chronic conditions that require medication. For example. I've always had high blood pressure, even when I was young and athletic, but as I got older, gained weight, etc, it worsened until I needed medication. Even now, after I turned things around, lost a ◊◊◊◊ ton of weight, I still need medication, but at a lower dose. Ditto cholesterol meds. High cholesterol seems to run in my family, but my meds, combined with a heart healthier diet, keeps my numbers beneath the recommended levels for someone with heart disease.
The problem with Oz is that he is often full of ◊◊◊◊, peddling psuedoscience as The Don pointed out. Like RFK Jr, he should be nowhere near our public health systems, but here we are.