What's worse for us: sugar or fat? To answer the hottest question in nutrition, twin doctors Chris and Xand Van Tulleken go on month-long high-fat and high-sugar diets. The effects on their bodies are shocking and surprising. But they also discover that in the debate about fat and sugar, the real enemy might have been hiding in plain sight.

The combustion of fuel and air in the engine and the fire in the heart of a rider willing to risk everything to win. Time is the enemy. The fractions of a second lost or gained in every corner which add up to defeat or victory. And the few years that you have to make it to the top. 'Hitting the Apex' is the story of six fighters - six of the fastest motorcycle racers the world has ever seen - and of the fates that awaited them at the peak of the sport.

Years after he changed the landscape of filmmaking with The Exorcist, filmaker and writer William Friedkin moves from fiction to fact with this documentary. What began as a brief conversation between Friedkin and Father Gabrielle Amorth - the head Exorcist for the Diocese of Rome for over 30 years - as two professionals who knew of each other's work, soon transformed into an once-in-a-lifetime opportunity, as Amorth agreed Friedkin could film an exorcism ceremony. It would be the ninth exorcism for a painfully afflicted woman, and it would be filmed by Friedkin alone, with no other crew allowed, no light other than the natural light in the room and a small digital camera-and-mic unit that could capture the ritual and its revelations.
Combining the startling and singular footage from Cristina's exorcism with interviews from priests and psychologists, neurosurgeons and non-believers, Friedkin guides us on a journey into the twilight world between the boundaries of what we know and what we don't.

Professor Alice Roberts journeys 40,000 years back in time on the trail of the great beasts of the Ice Age. Drawing on the latest scientific detective work and a dash of graphic wizardry, we bring the Ice Age Giants back to life. The series begins in the 'land of the sabre-tooth'; North America, a continent that was half covered by ice that was up to two miles thick. Yet this frozen land also boasted the most impressive cast of Ice Age giants in the world. Across locations such as the Grand Canyon, the sands of Arizona and the coast of California, Alice traces the movements of Ice Age beasts like bear-sized sloths, vast mammoths and the strange beast known as the glyptodon. These leviathans all have one thing in common: they were stalked by the meanest big cat that ever prowled the Earth, armed with seven-inch teeth and hunting in packs - Smilodon fatalis, the sabre-toothed cat.

Tyson begins the episode by explaining the nature of the speed of light and how much of what is seen of the observable universe is from light emanated from billions of years in the past. Tyson further explains how modern astronomy has used such analyzes via deep time to identify the Big Bang event and the age of the universe. Tyson proceeds to describe how the work of Isaac Newton, William Herschel, and James Clerk Maxwell contributed to understanding the nature of electromagnetic waves and gravitational force, and how this work led towards Albert Einstein's Theory of Relativity, that the speed of light is a fundamental constant of the universe and gravity can be seen as distortion of the fabric of space-time. Tyson describes the concept of dark stars as postulated by John Michell which are not visible but detectable by tracking other stars trapped within their gravity wells, an idea Herschel used to discover binary stars. Tyson then describes the nature of black holes, their enormous gravitational forces that can even capture light, and their discovery via X-ray sources such as Cygnus X-1. Tyson uses the Ship of Imagination to provide a postulate of the warping of spacetime and time dilation as one enters the event horizon of the black hole, and the possibility that these may lead to other points within our universe or others, or even time travel. Tyson ends on noting that Herschel's son, John would be inspired by his father to continue to document the known stars as well as contributions towards photography that play on the same nature of deep time used by astronomers.

The final episode of the series ponders the fate of planet Earth. Neil deGrasse Tyson opens with a reflection on science and those who help us understand it: 'We all feel the weight of the shadows on our future, but in another time, every bit as ominous as our own, there were those who could see a way through the darkness to find a star to steer by.'
The young Carl Sagan and Neil Tyson first discovered their passion for science at the NY World's Fairs of the past. We visit the dazzling Pavilions of the 2039 NY World's Fair, where problems we currently think intractable have been plausibly solved through public commitment and scientific imagination. And our baby is a woman now, with a baby of her own and a future bright with possibilities.