In 2014, Rob Barnett, an economist at Bloomberg, appeared on Bloomberg TV to discuss the Keystone Pipeline. The interview went well, but the footage of the segment gave Barnett a shock. “I’ve gotten fat,” he said to Christopher Payne, then a colleague at Bloomberg. Payne, who’d been overweight himself once, and who brooks no illusions about weight loss, replied to Barnett that he hadn’t gotten fat—he was fat.

Barnett and Payne thereafter became friends (honesty is everything), and though they parted ways professionally—Payne now works for the Kuwait Institute of Banking Studies—they have, for the past few years, been devising an approach to diet that uses the discipline they know best: economics.

In The Economists’ Diet (Touchstone, Jan. 2018), they present a guide to weight loss that reimagines food as “supply” and hunger as “scarcity,” gustatory restraint as “austerity” and careful eating as “budgeting.” PW spoke with the authors about how their program works.

Economics is a discipline rooted in data. How does that figure into your book?

RB: After that initial conversation [with Payne], the first thing I did was go out and get a scale, and I started weighing myself every day. One of the key features of the book is: You’ve got to start applying data and looking at how your behaviors on a daily basis affect your weight the following morning. Most diet advice focuses on “eat this food, not that food.” We didn’t talk about food at all. But we did spend a lot of time talking about behavior.

Your book references the idea of austerity. How can a dieter incorporate the concept into his behavior?

CP: From our perspective, as economists, one of the big economic problems is that people undervalue the future. They don’t think enough about future costs when they’re making consumption decisions. There’s an instant-gratification problem. What you need to do is impose eating austerity [on yourself]. You’re trying to impose scarcity—to pretend, if you like, that food is more scarce than it is.

RB: Intellectually, I know that I shouldn’t eat a bag of Doritos very often. But I love Doritos. When you’re in the moment, it’s very difficult to have clear thinking. The metric you get by weighing yourself on the scale every day helps you to clarify your thinking about food generally.

Your book also uses the concept “diminishing returns.” How does it factor in here?

CP: I eat the same thing [over and over again]: a piece of grilled chicken, or some kind of grilled meat, and vegetables. That leaves space for the occasional splurge; we can “budget” for that. [But more important,] because I have it all the time, there’s a diminishing marginal utility that comes from having it. Because the meals aren’t thrilling, I don’t need to stuff my face with them.

Why do you think an economic framework makes for a good approach to dieting?

RB: Economics gives you a very structured way to look at almost any kind of problem. We apply that to discipline of thinking to weight, but you could apply it to many other things.

CP: We’re bringing a different language. That’s the thing about economics. It’s not just that it explains things to us. It’s an alternative language through which to think through the problem of diet.

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