It is time to see if personalised dieting will work in normal life. The volunteers have been given one of three diets to follow - based on their genes, their hormones and their psychology. But now they are back at home, trying to stick to their personalised diets with all the stresses and temptations of real life. Dr Chris van Tulleken and Professor Tanya Byron discover how our genetic makeup can make temptation difficult to resist, how understanding the brain reveals what makes us comfort eat and what science can tell us about why we make disastrous food choices.

A look at how the Sun was formed and how it could potentially die; its physical composition; how it makes energy; and the nature of solar eclipses, solar flares and sunspot activity. Behold the sun and all of its glory. Learn all things about the sun ranging from its beginning to its death. Also learn about how stars work in general and MUCH, MUCH more.

The Earth was formed by a series of cosmic cataclysms including the most powerful blast in the Universe. Yet amid the turmoil our world was born. Could the same chain of events have created other earths elsewhere, inhabited by creatures like us?

Of the four elements, air is the most elusive because we can't see it. There's something very magical about it. One of the ways we transform food is by getting air into it. Think of the soufflé, think of the loaf of bread. These things are elevated by the fact that they now contain air. They're ethereal. Visit food labs and Moroccan fields as Michael Pollan delves into the science of bread-making and the nature of gluten.

One animal embodies all that is amazing about survival. It has adapted to wildly varying habitats and evolved unique weapons of survival; its greatest asset is its ferocious bite and it is evolutions ultimate survivor, but what species is it? Find out if a new bear species could be about to evolve before our very eyes.

We feel it every moment of our lives but for physicists, gravity is the longest running unsolved mystery of the universe. Why do all objects that have mass pull on one another? Cutting-edge theories are proposing unexpected answers: Gravity could be another force in disguise, a thermodynamic mirage, or even, a shadow of a hidden holographic universe. If so, the force that holds us to the surface of the earth, and holds the earth in orbit around the sun, may be a trick of the mind. We feel it, but it may not be real. Is Gravity an Illusion?