Grabbing lunch used to be so simple. Guys would take their spears and hunt down a mastodon, while ladies gathered fruit from the nearest trees or bushes. Meet back at the cave, and voilà — you’d have a fresh and healthy meal.

Today, eating organic requires far more resources and research. One must find out what’s really grass-fed or naturally-grown, have access to the right supermarket, and of course, be able to afford top-quality products. In return, you get the good feeling of supporting small and local businesses, and proper nourishment.

But economist Tyler Cowen argues you don’t have to have this star-alignment of assets in order to eat well and still manage to pay rent. He will discuss his newest book, An Economist Gets Lunch: New Rules for Everyday Foodies (Dutton Adult, April 2012), at Arlington Central Library at 7 p.m. on Wednesday, April 3.

Cowen argues that “just about everything you’ve heard about food is wrong,” but that is pretty great news in this case. An Economist Gets Lunch brings together Cowen’s expertise as an economist, social commentator, and dining blogger in order to make recommendations relevant to D.C. dwellers. For example, he recommends avoiding restaurants filled with beautiful women in busy city centers (go for the ones where patrons are grim-faced or yelling at each other), and advises how to select the best food at airports, street vendors, and most places in-between. He covers a range of dining issues encountered by foodies as well as average eaters: The optimal way to grocery shop, ingredients and other factors to look for on a restaurant menu, the merits of barbequing, and how to make the most of cooking at home.

Despite Americans’ growing interest in organic and local eating, Cowen says, the rates of obesity and diabetes continue to increase. But fear about contributing to global warming and environmental harm has also had an effect on how we eat. Among the many pointers in An Economist Gets Lunch, Cowen reassures the reader that consuming a little less meat will go a long way in the environment department, compared to only eating locally.

Although, Cowen has also said, if you are really attached to that virtuous-eating feeling, vegetarian is the way to go. Something to chew on.

Cowen is a professor of economics at George Mason University and coauthors the economics blog “Marginal Revolution.” He writes the “Economic Scene” column for The New York Times, and also writes for publications such as The Wall Street Journal, Forbes, The New Republic, and more. He has published numerous books and other works including the popular and controversial The Great Stagnation, on how the U.S. economy’s technological plateau explains much of its current problems.

Wednesday’s event is free and open to the public.