Plenty of audiences have warned: don't see the new French movie The Taste of Things on an empty stomach. Juliette Binoche plays a longtime personal cook to a man who's a gourmand（美食家）. They share a passion for food. Filled with delicious meals, the film celebrates food, and all the work and love that go into making it.

When you see a delicious meal in a movie or an ad, chances are that it's not fit to eat. Food stylists have been known to substitute glue for milk, and coat meat with motor oil. All this was a big "No" for Vietnamese French director Tran Anh Hung.

Tran says he wanted everything in The Taste of Things "to be real," from the raw ingredients（食材）to the menu to the way the cooks move in the kitchen. Real food can't always handle multiple takes. Plus, Tran needed to show dishes at different stages of preparation. So he needed a lot of everything. For a classic French dish, "we needed 40 kilos of meat for the shooting." He also had to find vegetables that looked like they were harvested in the 19th century. "They're not as beautiful as today," he says, "They're not straight, and they have many spots on the skin."

After doing extensive research into the history of French cuisine and working with a historian, Tran enlisted three-star chef Pierre Gagnaire to make sure the menu he'd come up with worked in real life.

Gagnaire also cooked for Tran for five days, so the director could study his movements in preparation for filming. Tran says watching Gagnaire move around the kitchen taught him that "simplicity is important and you don't need to have the perfect gesture for this or that. You need only to be very free." Gagnaire says the movie feels like a gift. "For my creativity, it's an honor," he says. The famous chef agreed to take a small part in the film.

"When you leave this film, you feel calm because instead of violence, there's tenderness," Gagnaire says.

Why did humans evolve to walk upright? Perhaps because it's just plain easier. Make that "energetically less costly," in science-speak.

Bipedalism — walking on two feet — is one of the defining characteristics of being human, and scientists have debated for years how it came about. In the latest attempt to find an explanation, researchers trained five chimpanzees to walk on treadmill while wearing masks that allowed measurement of their oxygen consumption. The chimps were measured both while walking upright and while moving on their legs and knuckles. That measurement of the energy needed to move round was compared with similar tests on humans and the results are published in this week's online edition of Proceedings of the National Academy of Sciences.

It turns out that humans walking on two legs use only one quarter of the energy that chimpanzees use while knuckle-walking on four limbs. And the chimps, on average, use as much energy using two legs as they did when they used all four limbs.

However, there were differences among chimpanzees in how much energy they used, and this difference corresponded to their different gaits and anatomy. One of the chimps used less energy on two legs, one used about the same and the others used more, said David Raichlen, assistant professor of anthropology at the University of Arizona.

"What we were surprised at was the variation," he said in telephone interview. "That was pretty exciting, because when you talk about how evolution works, variation is the bottom line, without variation there is no evolution."

Walking, on two legs freed our arms, opening the door to manipulating the world, Raichlen said. "We think about the evolution of bipedalism as one of first events that led hominids down the path to being human."

The research was supported by the National Science Foundation and the L. S. B. Leakey Foundation.

Just as China sets the world pace in e-commerce（电子商务）, it's doing the same for live streaming. More than 100 million viewers watch a live online video event every month. As an e- commerce tool, the live streaming format typically involves a famous person showing a product and answering questions from a digital audience. It takes place in real time （实时） and usually on a smartphone, which accounts for some 95% of e-commerce activity in China.

China is filled with live streaming webcasts, much of it non-commercial, such as young people discussing their lives, offering diet tips, etc. But live streaming has also become one of the most cost-effective tools for e-commerce in China.

Why are consumers and brands both hugging live streaming?

First, there's a functional advantage to live streaming. It allows experts to show the product being used, to show various techniques, and to point out the results. There's also a feeling of authenticity（真实性）that comes from livestreaming because the audience can interact（互动）with the experts by asking questions in real time.

Consumers feel that they are actually handling the product themselves. Instead of picking a product off a shelf, they are now part of the process, shaping the outcome from the convenience of the living room sofa. The best live streaming allows room for a joke, or even a small mistake. After all, this is how friends talk with one another. As consumers grow in experience and taste, they would rather participate in a chat. Live streaming invites the brand into the home in much the same way you would invite a friend.

Consumers often feel a sense of empowerment （赋予权力）. The brand must react quickly and positively to viewers in real time because consumers have the power to hold them responsible for their products through questions.

Live streaming can also be particularly effective for new-to-market brands who do not have the ability to create a buzz because it provides a guarantee that the product is used, accepted and loved.