I received a new book titled The Obesity Code last week, written by Canadian nephrologist Jason Fung.
Over the last year, I had read a few things by Dr. Fung on his clinic’s blog, but one of the things he says about obesity in his book made me believe that the study of obesity has a lot in common with development economics. Specifically, on p. 216 of his book, Dr. Fung writes:
The multifactorial nature of obesity is the crucial missing link. There is no one single cause of obesity. Do calories cause obesity? Yes, partially. Do carbohydrates cause obesity? Yes, partially. Does fiber protect us from obesity? Yes, partially. Does insulin resistance cause obesity? Yes, partially. Does sugar cause obesity? Yes, partially. All these factors converge on several hormonal pathways that lead to weight gain, and insulin is the most important of these. Low carbohydrate diet reduce insulin. Low-calorie diets restrict all food in there for reduce insulin. Paleo and [low-carb, high-fat] diets reduce insulin. Cabbage-soup diets reduce insulin. Reduced-food-reward diets reduce insulin. …
Obesity is a multifactorial disease. What we need is a framework, a structure, a coherent theory to understand how all its factors fit together. Too often, our current model of obesity assumes that there is only one single true cause, and that all others are pretenders to the throne. Endless debates ensue. Too many calories cause obesity. No, too many carbohydrates. No, too much saturated fat. No, too much red meat. No, too much processed foods. No, too much high-fat dairy. No, too much wheat. No, too much sugar. No, too much highly palatable foods. No, too much eating out. It goes on and on. They are all partially correct. …
Without understanding the multifactorial nature of obesity–which is critical–we are doomed to an endless cycle of blame.
In his book, Dr. Fung proposes a multi-pronged strategy to fight obesity. It looks as though he knows what he is talking about, since he has apparently helped several patients return to a normal weight.
Having long toyed with the idea of developing a model of individual weight dynamics wherein an S-shaped fat accumulation curve leads to there being two equilibria, much as in the modified Solow growth model with poverty traps, what the above excerpt made me think of is the equally multifactorial nature of poverty. Indeed, one of the first things I teach students when I teach a development course is that persistent economic under-development–poverty, that is–is the result of multiple market failures. The corollary of that statement is that there are no silver bullets in development. So unless you tackle all the problems at once, you might make a small, temporary dent in poverty, but people will tend to slide right back to where they were–much like people who, say, cut their calories tend to lose weight in the short run, but tend to go right back up to were they were after a few months.
In practice, this means that in situations of persistent economic under-development, microfinance will not magically lift people out of poverty. Nor will an input subsidy program. Nor will a micro-insurance scheme. Nor will any single intervention not aimed at resolving multiple market failures at once. And lest you think this makes me an advocate of something like the Millennium Villages Project, it does not. At least not in its current form, which does not lend itself to rigorous impact evaluation.
(By the way, this is why I had a hard time with Why Nations Fail: Because the authors are some of the smartest people alive today, yet their rhetoric seems to suggest that economic under-development has a single cause: extractive institutions. The journal articles on which they base the book are a lot more nuanced, so I imagine a publisher asked them to be slightly more polemic in order to make the book make an argument that sells better.)
If it were so simple as simply providing people with micro-loans, poverty would be a thing of the past. Similarly, if it were simply a question of “eat less, exercise more,” obesity would be a thing of the past as well. But whenever someone is suggesting a simple solution to a persistent problem, it is a safe bet that you are probably being sold snake oil.
I don’t know if Dr. Fung is the originator of the claim that obesity is multifactorial. But my intuition is that the claim is correct, and I certainly hope it gains traction with the publication of Dr. Fung’s book. As to what Dr. Fung advocates to treat obesity, you will have no doubt guessed that he does not advocate any single thing. Rather, The Obesity Code advocates doing all of the following:
- Reducing one’s consumption of added sugars
- Reducing one’s consumption of refined grains
- Consuming a moderate amount of protein
- Increasing one’s consumption of natural fats
- Fasting for periods of 24, 36, even 48 hours
- Getting seven to nine hours of sleep every night
- Meditating