It is said that cooking is the way to a man’s heart. But according to Harvard Biological Anthropology Professor Richard W. Wrangham, cooking is the way to a good deal more than that.

In his book “Catching Fire: How Cooking Made Us Human,” released Monday, Wrangham argues that the invention of cooking allowed for our primate ancestors to become humans.

“We are the cooking apes, the creatures of the flame,” said Wrangham in an interview yesterday.

Wrangham bases his argument on wide-ranging scientific evidence, both biological and behavioral.

Looking at studies in nutritional science, Wrangham determined that cooked food is softer and more easily digestible.

“In this way,” he said, “cooking food increases the number of calories we get from it.”

This extra energy, Wrangham argues, allows humans to maintain their large brains. “Once you appreciate that point, you can understand that there has been an evolutionary adaptation taking advantage of cooked food.”

At the same time, easily digestible food frees the body from the task of chewing. Chimpanzees spend half their day chewing their food, energy not spent in more constructive activities, said Daniel E. Lieberman, a fellow anthropology professor and chair of department’s biological anthropology wing.

The book counters earlier hypotheses about human evolution, such as the theory that human evolution stemmed from eating meat, either raw or cooked.

The transition to cooking may have had social implications as well. Wrangham argues that the control of the flame gave rise to traditional gender roles, as cooked food became a valuable commodity.

“The possibility of [food] theft prompted a primitive protection racket in which women are protected and men get the advantage of being fed,” he said.

In previous research, Wrangham studied chimpanzees, even working with famous primatologist Jane Goodall in Tanzania.

“They are a good model for human ancestors 6 to 7 million years ago,” he said of the early primates.

It is while observing chimpanzees that Wrangham said he began to consider a link between eating and evolution.

“I would go for hours, all day, watching chimpanzees and relying only on their food. I realized that we are not well adapted to eat chimp foods,” said Wrangham.

The cooking thesis has raised excitement among Wrangham’s colleagues, according to Lieberman.

“We take behaviors like cooking and food preparation for granted,” Lieberman said, “but we are obligate cookers. To be honest, nobody had really thought about it before Richard.”

—Staff writer Madeleine M. Schwartz can be reached at mschwart@fas.harvard.edu.