Chronic disease has many definitions—but perhaps the best one is: how well your mitochondria perform at baseline and in response to the stress of living and eating. If your mitochondria are fresh, fit, and functional, it doesn’t matter how much you weigh. If your mitochondria are dull, dilapidated, and under duress, it also doesn’t matter how much you weigh. But there’s no simple blood test for mitochondria,
