In part one, Caroline convinces volunteers to road-test four popular diets: Keto, Paleo, 5/2 and Flexitarian, Sandro examines which milks are healthiest, Shalin investigates if going gluten-free is safe.

In part-two, Caroline's diet experiment reveals spectacular weight-loss, along with worrying health implications. Shalin lifts the lid on fats and oils and Sandro navigates Australia's confusing food labelling system.

Being lonely is the silent health crisis deadlier than obesity. The doctors explore why and give advice on how to make new friendships that last.