Gary Taubes

as Self - Investigative Science Journalist / Author

Nina Teicholz

as Self - Investigative Science Journalist / Author

Ancel Keys

as Self (Archival footage) - Physiologist

Tim Noakes

as Self - Scientist / Author / Professor Emerita

Mark Hyman

as Self - Narrator / Nutritionist / Functional Medicine Physician

Bret Scher

as Self - Cardiologist

Sarah Hallberg

as Self - Obesity Specialist

Zoe Harcombe

as Self - Obesity Researcher