How to Use Economic Theory to Lose Weight

Two formerly obese economists say the key to losing weight is to use basic principles such as austerity, meta-rules, and budgeting.

Illustration: Yann Kebbi

I’ve always been drawn to unconventional diets. I was raised as a vegetarian, and at different points in my life I’ve characterized my diet as vegan, macrobiotic, Atkins, low-carb, paleo, or keto. (Yes, I’m really popular at dinner parties.) It hasn’t been torture. In fact, I enjoy the tinkering.

Of course, around the world, not everyone has this luxury. The economy is a huge determiner of what we eat. The premise of the book The Economists’ Diet is to take insights from broad global issues and apply them to personal dietary behavior. Authors Christopher Payne and Rob Barnett observe that many of us live in a world of abundance: In wealthy, developed markets, cheap food is everywhere, and so obesity has skyrocketed. Payne, a financial stability expert, and Barnett, an analyst of the politics of fossil fuels, met while working at Bloomberg LP (Barnett still does) and soon found themselves obese, after endless rich dinners with clients and fast lunches from McDonald’s.

They write about their efforts to lose weight by applying the lessons they learned studying economics. By now, there’s been enough behavioral work inspired by Freakonomics (and its various ripoffs) to recognize that the field may have a lot to teach us in this area. For them, it meant losing a combined total of 120 pounds over 18 months.

A primary argument of the book is that to lose weight, we essentially need austerity. The authors liken obesity to a government going deep into debt. Eventually you have a choice to make: a catastrophic default (a bad health event) or an uncomfortable reduction in government spending (eating less). We need to set our own conditions of scarcity amid this abundance. How do we do this? One approach, drawn from the work of behavioral economist Dan Ariely, is to set meta-rules. For example, rather than trying to decide what to eat every day for lunch, just come up with a simple rule that you’ll only have salad. Remove the temptation to even consider a bad decision. (You are going to be unhappy and hungry at times.)

The book is filled with various behavioral approaches to good decision-making that won’t really surprise you (but that, also unsurprisingly, work): Buy groceries online to reduce temptation, make a habit of saying no to bread and chips, always order the smallest size, cook at home, and don’t eat if you’re not hungry. One thing that makes Payne and Barnett’s work distinct from most diet books is the relative lack of discussion about nutrition. They’re economists, not medical professionals, and it’s refreshing to read a book and not have to wonder whether the science is bunk.

The Economists’ Diet diverges with some popular thinking about weight loss. Earlier this year, I read Dr. Jason Fung’s fantastic The Obesity Code, based on his experience treating people with Type 2 diabetes, which argues that, ultimately, cutting calories is a failed idea. Fung posits that your body will just adjust to a new equilibrium, and you’ll never be able to sustain feeling hungry. He advocates instead for a low-carb, high-fat diet that leaves you with reduced insulin levels but satiated. Like Fung, Payne and Barnett argue for skipping meals, but for different reasons. Fung believes fasts are important, leading to long periods of low insulin levels; Payne and Barnett mostly see skipping as a chance to reduce calories. It’s a basic economy.

The Economists’ Diet is not a panacea. Rather, it’s an enjoyable account of the thought process of two non-diet professionals who hacked their way into a system that worked for them. Economics is ultimately about building a toolbox to analyze different problems; the beauty comes when we put those tools to work in a new space.

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