Couples take part in the “Love and Challenge Marathon” in Hanoi, Vietnam, 16 August 2015. Fifty couples, who are going to get married, participated in the event which is held the fifth time. This year, the winners of the marathon received a honeymoon trip to Malaysia. (Photo by Luong Thai Linh/EPA)

Alex Plunkett, left, and Sean Hart, both of Arlington, Va., join hundreds participating in the annual International Pillow Fight Day on April 5. Massive pillow fights broke out on the Mall in Washington and in cities around the world. (Photo by Marvin Joseph/The Washington Post)

In this handout photo provided by Warner Brothers Pictures and Village Roadshow Pictures, Tom Cruise plays Lieutenant Colonel Bill Cage, a soldier who replays his last day while trying to fight aliens, in director Doug Liman's “All You Need Is Kill”. The film is set to premiere on March 14, 2014. (Photo by David James/Warner Brothers Pictures)

A participant of the “Mrs Universe 2015” contest from Caribbean Coast, Mayra Joli poses for a photo with a woman during their visit in central botanical garden in Minsk, Belarus, August 25, 2015. (Photo by Vasily Fedosenko/Reuters)

A subway worker walks away after a train departed the station in central Pyongyang, North Korea May 7, 2016. (Photo by Damir Sagolj/Reuters)

UConn students from Storrs, Conn., Gary Tu, Danny Wang and Victor Zheng, fish at Shenipsit Lake in Tolland, Conn. during sunset on Tuesday, August 19, 2014. (Photo by Jim Michaud/AP Photo/Journal Inquirer)

A stunning photographic collection featuring portraits of people from 30 countries and the food they eat in one day. In this fascinating study of people and their diets, 80 profiles are organized by the total number of calories each person puts away in a day. Featuring a Japanese sumo wrestler, a Massai herdswoman, world-renowned Spanish chef Ferran Adria, an American competitive eater, and more, these compulsively readable personal stories also include demographic particulars, including age, activity level, height, and weight. Essays from Harvard primatologist Richard Wrangham, journalist Michael Pollan, and others discuss the implications of our modern diets for our health and for the planet. This compelling blend of photography and investigative reportage expands our understanding of the complex relationships among individuals, culture, and food.

Visitors crowd an artificial wave swimming pool at a tourist resort to escape the summer heat in Daying county of Suining, Sichuan province, China, July 11, 2015. (Photo by Reuters/Stringer)