<br><div><img src="https://www.washingtonpost.com/wp-apps/imrs.php?src=https://cloudfront-us-east-1.images.arcpublishing.com/wapo/7WW7XNLDM5HMLCE2YGJ6PTTWPY.jpg&w=1440" style="width: 100%" /><div>Once upon a time, it was fat. Then it was gluten. Some people still think it’s sugar. The latest fallacious magic bullet? Insulin.</div></div>