Should Marty Makary take the reins at the FDA, transitioning from gadfly to the head of an agency that regulates a fifth of the U.S. economy, he would have to engage in the thorny challenges of governing.

If confirmed, Makary would run one of the nation's leading health agencies, overseeing the regulation of food and drugs.

Marty Makary, President Trump’s pick to lead the Food and Drug Administration (FDA), will testify before the Senate Health, Education, Labor and Pensions Committee on Thursday morning.