Christopher Greenslate, co-author of “On a Dollar a Day,” described his month-long experiment in which he limited his daily food budget to one dollar and encouraged increased discussion of the origins and costs of food at an event hosted by the Food Law Society at Harvard Law School yesterday.

Greenslate, a high school teacher near San Diego, said he undertook the project after a complaint about rising food prices during a grocery store visit led him to reflect on the travails of people who have little money to spend on food.

In September 2008, he and co-author Kerri Leonard each ate only a dollar’s worth of food per day, forcing them to subsist on items such as oatmeal and beans, with a dollop of peanut butter as an indulgence.

“This is not anything I ever intended,” Greenslate said, explaining that what began as a blog-documented personal curiosity led to him being contacted by The New York Times and ultimately publishing a book about his experience and the issues that it illuminated for him.

Greenslate also addressed policy issues in his talk and even made specific pleas to the Harvard Law School students in attendance to take action on matters such as transparency in the food industry.

Greenslate was invited to the Law School by the Food Law Society, a group approved last month that was founded by third-year Law School students Michelle S. Ahmadian and Nathan A. Rosenberg to increase attention to food issues.

Rosenberg said that he thought Greenslate’s comments on policy were an especially valuable aspect of his visit.

“It’s important for law students to realize the impact they can have,” Rosenberg said.

First-year Law School student James R. Tager also said that it was “really refreshing” to hear Greenslate address not only the need to examine one’s individual behaviors, but also the importance of using one’s education to create change on a broader scale.

First-year law student Lara N. Berlin said she found Greenslate’s emphasis on self-awareness important because “people of means” are often not conscious of the significance of the food choices they make.

Greenslate said that people should start with a self-study to assess their own awareness of the personal choices they make about food.

He recommended beginning by asking oneself, “Why do I eat what I eat?” and “Is my behavior in line with my values?”

“I want people to know that you really are in control of your food choices,” he said.