I find myself getting asked this question, or some variant of this question, with increasing frequency as I speak and write about the Alternative Hypothesis I find most compelling surrounding obesity and chronic disease. One implication of the Alternative Hypothesis, as you probably understand by now if you’ve been reading this blog, is that many carbohydrates, especially if consumed at the levels most Americans consume them, promote fat gain. In other words, overweight people are not the lazy, constantly grazing, weak-willed individuals many in the mainstream have led us to believe. They just eat the wrong foods (rather than simply too much food).
Remember, I was one of those doctors in the mainstream once upon a time. While I always tried (and hopefully succeeded most of the time) to treat overweight patients with respect, I silently judged them. Why can’t you just eat less and exercise more? Only when I realized, despite my diet which rigorously adhered to formal recommendations and my 3 to 4 hours of exercise per day, that even I was getting too fat for comfort, did I begin to question the Conventional Wisdom of why we get fat. Of course, not everyone (fortunately) was born with my level of genetic susceptibility toinsulin resistance (stated another way, not everyone is born with my level of carbohydrate sensitivity). In my experience, about 10-20% of the population (my lucky wife included) seem resistant to carbohydrates and maintain exquisite insulin sensitivity, almost independent of diet. Roughly 30-40% of the population are, conversely, very sensitive to carbohydrates and appear to be quite insulin resistant until nearly the last gram of sugar and most carbohydrates are removed from their diets. Then there is the rest of population, which includes me. To varying degrees, we’re somewhere between these two groups.
So back to this question — If carbohydrate reduction is so effective for weight loss, why are so many people still overweight? Beyond being asked this question, personally (and frequently), one can see the same logic in the academic literature (see comment by George Bray in Obesity Reviews) and in the press (see comment by Gina Kolata in the New York Times).
George Bray: “I thus conclude that if any diet ‘cured’ obesity as their proponents often claim, there would be no obesity and thus no need for the next diet. Yet the past 150 years, since the publication of Banting’s first popular diet*, have seen a continuing stream of new diet books.”
Gina Kolata: “Low-carbohydrate diets have been popularized periodically since the 19th century. Best-selling book after best-selling book promoted them. Yet if they work so well, why are so many people still searching for an effective way to lose weight?”
*If you have not yet done so, and you’d like to put yourself in the ‘low-carb aficionado’ club, you must spend time reading the work of Banting.
Dr. Bray is generally regarded as one of the most erudite authorities on obesity in the United States, while Ms. Kolata is one of the leading reporters on the topic – so we’re not just talking about “anyone” asking such questions. Bray and Kolata are both smart and thoughtful people who have devoted much of their lives to thinking about this problem. In other words, we’re actually all on the same “team” – we desperately want to help people lead more fulfilling, healthy lives by improving their eating habits. But we disagree on this point.
It seems Dr. Bray and Ms. Kolata (and many others) have proposed (implicit in their statements) an interesting “Principle,” below:
If a disease is prevalent, no treatment exists to eradicate it. In other words, if any condition exists, it implies there is no cure for that condition. The reverse (and logically equivalent) statement is this: if a treatment exists for a disease, no one has the disease.
Is this a valid criticism of carbohydrate restriction? Perhaps, but to be sure let’s consider a few examples of this Principle.
- Polio no longer exists in the United States, thanks to the development of two types of vaccines to immunize people against the poliovirus.
- Smallpox, a viral disease estimated to have taken between 300 and 500 million human lives in total, no longer exists thanks to two vaccines that eradicated the disease in 1979.
- Breast cancer still exists, and in 2011 claimed the lives of 40,000 women in the United States alone. While there are many treatments for breast cancer (surgery, radiation, chemotherapy, and combinations of these) depending on stage of disease, no cure exists to eradicate it once it is systemic (i.e., spread throughout the body), which is consistent with the Principle. [Remember “logic 101” tells us that if A implies B, no-B implies no-A.]
So far the Principle seems pretty compelling. Of course, to be an all-singing-all-dancing-universal-truth, there cannot be any exceptions to this Principle. Do any such exceptions exist?
- HIV, when progressed to AIDS, is responsible for nearly 2 million annual deaths worldwide (about 16,000 deaths per year in the United States), yet transmission of the HIV virus – the causative agent – is entirely preventable. Furthermore, the current drug regimen for HIV can prevent nearly all patients with HIV from progressing to AIDS, thereby rendering HIV a chronic disease.
- Malaria, a disease transmitted by mosquitoes, is responsible for about 1 million deaths worldwide each year, yet this disease can be prevented successfully via two broad strategies: prophylactic treatment with anti-malarial agents (this is typically what folks do when traveling to regions where malaria is prevalent) and use of anti-mosquito “technology” (e.g., nets, DEET). Furthermore, when a person, despite these measures, contracts malaria, prompt treatment with anti-malarial drugs will cure most.
- Polio, which has been eradicated in the Western world, is still prevalent in south Asia despite a clear method of prevention.
For the purpose of space and time I’ll stop here with examples, but it turns out there are far more examples of the Principle being violated than being upheld. In other words, the Principle isn’t actually a Principle. It’s an idea that is true less often than it is false. Sort of like the idea dogs and children should never be together (which I used to believe after many years of suturing up the faces of children who had been ravaged by dogs). I now realize that most children around most dogs are perfectly safe, and adult supervision can make the odds even better.
What is the common theme in each of these examples that defy the Principle?
It’s probably a combination of factors, and they differ across the examples, too. Let me use HIV as an example of this phenomenon. I did my residency in general surgery at the Johns Hopkins hospital in Baltimore, Maryland. For those of you not familiar with Baltimore, some background is warranted. In the final weeks of medical school I took the advice of a friend and read the book, The Corner, by David Simon and Ed Burns. This riveting true story was the single most valuable book I could have read prior to moving from posh Palo Alto to inner city Baltimore. Through this book, other books, and eventually my own personal experience, I came to realize how Baltimore had become the heroin capital of the United States. Furthermore, because of where Hopkins is situated in the city, I would come to spend many years taking care of patients in the emergency room and hospital wards who battled heroin addiction.
As a result of such high rates of heroin addiction, the number of patients walking (or being carried into) the Hopkins ER was very high. If I recall correctly, and these numbers do change over time, approximately 60% of patients walking (or being carried) into the Hopkins ER were positive for HIV, hepatitis B, and/or hepatitis C. Each of these diseases is transmitted through blood or other bodily fluids. Needle sharing and sexual transmission are far and away the most common modes of transmission in the United States today.
Preventing HIV, hepatitis C, and hepatitis B is pretty straight forward today. If you have sex, especially with “high risk” individuals, do so with a condom. If you use IV drugs, do not share needles. One could even go a step further and not use IV drugs at all and not have sex with high-risk individuals (e.g., prostitutes). [Hepatitis B, while 10x more transmissible than hepatitis C and 100x more transmissible than HIV is the only one of these three viruses for which there currently exists a vaccine.] While there are other ways these three viruses can get transmitted, practically all (>99% as of 2007) are contracted through these two routes of transmission in the United States.
Furthermore, the treatment for HIV using a treatment regimen called HAART (Highly Active Anti-Retroviral Therapy) has become highly efficacious at preventing HIV from even progressing to AIDS. In other words, if one contracts HIV today, it’s quite likely to prevent HIV from progressing to AIDS.
How can it be possible, you ask, that anyone can contract a disease that is so easily preventable? Furthermore, for those who have contracted the disease, how can so many go without treatments that would easily render their condition a chronic one – a condition that will not lead directly to their death — rather than a condition that will lead to their death?
Information, infrastructure, and pain
One could (and I’m sure several have already done so) write an entire dissertation on this exact topic. At the risk of oversimplifying, though, let me briefly explain why I believe a disease that has apreventable cause and effect can still exist. There are three broad reasons, though they are not all equally contributory nor are they constant for all people (i.e., the dominant reason for one person might be less relevant for another person).
While it might be “obvious” to many of us, it’s actually not clear to everyone that a virus can cause a disease like AIDS. Heck, most folks don’t actually know what a virus even is. Furthermore, some people do not know how the virus is transmitted or how, exactly, to prevent this transmission.
In the United States today, the group of people who contract HIV primarily because of what I call “poor information” is probably quite low. But in Africa, for example, this probably plays a significant role in transmission.
Even if one realizes how the HIV virus gets transmitted and what the consequences are (i.e., “poor information” is not an issue), another feature – poor infrastructure – can play a role in facilitating spread of the disease. While condoms and clean needles can greatly reduce the transmission of HIV, accessing them is not always easy, especially if one is on a tight budget, as many folks addicted to heroin are. And while programs exist to literally give away needles and condoms, not everyone can access them in a time of need.
Pain versus consequence
Why do people use HIV infected needles when they can find clean needles at a shelter? Why do people have sex with prostitutes without using condoms, even though they can access condoms for free? I don’t think there is one clear reason or explanation. Some of it is social support and surroundings. Some of it is prioritization. Some of it is pain. Perhaps the pain transiently ameliorated by heroin or sex is deeper than the long-term cost?
What have we learned?
- A disease can exist despite a means of prevention.
- A disease can exist despite an effective treatment.
- The barriers to prevention and treatment are likely multi-faceted and complex (and highly dependent on the disease).
While I’ve only used HIV (and by extension, hepatitis C and hepatitis B) to illustrate this point, I hope I’ve given you some idea how someone can still “get” a disease, while living in the United States circa 2012, despite all of the good information and infrastructure to prevent it.
As you undoubtedly know, the problem is far worse outside of the United States. In many parts for the world the people being afflicted with HIV lack even the correct information, let alone a shred of infrastructure to combat the problem.
Back to the original question
How does obesity stack up? Let’s evaluate using this framework.
Unlike HIV which, at least in the United States, is appropriately understood, the study of nutrition and obesity is a relative debacle. The formal recommendation of the USDA, AHA, AMA, ADA, and others actually tell us to eat the foods that make approximately two-thirds of us overweight.
Try asking your doctor for help, and you’re likely told to eat less food, eat less fat, eat more grains, and exercise more, stupid.
Since approximately 1972, U.S. food policy has almost monotonically been shifting further and further towards all but making it impossible to avoid carbohydrates. Countless books have been written about this topic from many levels from agricultural subsidies to the lobbying powers of those who sell sugar.
The results of these actions are particularly devastating on those individuals who are not affluent. If you wonder why the economically disadvantaged are more likely to be obese, ponder this: one can buy ten boxes of ramen noodles for one dollar at most grocery stores. On a per calorie basis, few things are cheaper than sugar and other carbohydrates.
If you’re hungry in an airport or a mall (or virtually anywhere out of your own home), how easy is it to avoid sugars and simple carbohydrates?
Like Dr. Rob Lustig has said on many occasions, I don’t believe anyone chooses to be overweight. I do believe most people who are overweight are so because of poor information and poor infrastructure. However, these two features are not the only reason. Many people still smoke cigarettes today in the United States, despite good information (i.e., everyone “knows” smoking is harmful) and good infrastructure (e.g., cigarettes are very expensive and most places don’t allow smoking – the default action is not to smoke). There’s another reason people smoke. Similarly, some people will always turn to the wrong foods. I guess, for some, the acute pleasure food brings outweighs the chronic pain it causes, even when information about food is clear and unambiguous and when infrastructure does not essentially force people to eat the wrong foods.
I don’t know how much of a role this feature will play when the former two features are one day corrected, but I’m sure fixing the former two will go a long way to reversing the epidemic we find ourselves living and dying in.
Should we be surprised that 67% of Americans are overweight and that nearly 10% have diabetes?
We are outright told to eat the foods that make us fat via all formal and informal recommendations. We are surrounded by food infrastructure that makes our “default” eating patterns in line with those (flawed) recommendations. And for those of us who decide to go against the grain and overcome these two enormous hurdles, we are almost assuredly not supported. In fact, we’re often condemned and ridiculed.
While I greatly respect Dr. Bray’s and Ms. Kolata’s commitment to fighting obesity, diabetes, and their associated chronic diseases, I reject their reasoning for why reducing carbohydrates is not one of the most effective treatments.