Gary Taubes has written two books explaining why people get fat and why a low-carb diet is the solution to preventing and treating obesity. He didn’t like what I had to say about his books on this blog back in 2011. I was not the only one to criticize. Another reviewer accused him of “abandon[ing] journalistic and scientific integrity in place of observational data, straw men and logical fallacy.” He says he agrees with Taubes’ premises but that his “arguments made me cringe,” and he goes into considerable detail to explain why. His analysis is worth reading.
Rather than engaging in the Comments section, Taubes complained to me in a somewhat offensive personal e-mail, saying I had failed to understand what he wrote. Recently he e-mailed me again, condescendingly suggesting that I might understand his arguments better if I read an article he wrote last year for the British Medical Journal. I read it, and confirmed that I had understood perfectly well the first time around and that it was Gary Taubes who didn’t understand my criticisms. I pointed out some omissions and inconsistencies, but my major criticisms boiled down to two:
- The clinical evidence isn’t yet sufficient to convincingly prove his thesis. (He himself admitted this.)
- He strongly recommended that everyone adopt a low-carb diet, essentially insisting that we act on insufficient evidence. And this was after he had devoted whole chapters of his books to demonizing the low-fat diet advocates for doing exactly that: acting on insufficient evidence.
In medicine, particularly oncology, it’s often the little things that matter. Sometimes, however, the “little things” aren’t actually little; they just seem that way. I was reminded of this by a story that was circulating late last week in the national media, often under titles like “Obese cancer patients often shorted on chemo doses”, ”Are obese people with cancer getting chemotherapy doses too small for them?”, and “Obese Cancer Patients Not Getting Full Doses of Chemotherapy Drugs”. It’s also interesting to me because it stands in marked contrast to something I’ve written about a lot on this blog: The overtreatment of cancer. In this case, this story is about the undertreatment of cancer in patients who are obese, and it’s a problem that has definite adverse effects on an obese person’s odds of surviving cancer.
I’ve been aware of this issue for some time and had been thinking of blogging about it for at least three years. The reason is that the oncologist who is best known for sounding the alarm on this issue is Jennifer Griggs at the University of Michigan and, being local and all, I’ve seen her speak on the topic several times at local breast cancer conferences. Now that I work with a statewide breast cancer care quality improvement initiative, I’m becoming more aware of her work. Indeed, I was rather puzzled why this issue bubbled up enough to be reported widely on the national news last week when the Nature Clinical Oncology paper by Gary H. Lyman and Alex Sparreboom that drew attention to the issue was published in August, and the original American Society of Clinical Oncology (ASCO) guidelines were published last year. Whatever the reason this issue has been getting more attention, it’s a good thing.
In the past I have criticized evolutionary medicine for its tendency to rely on unverifiable “Just-So Stories,” but a new book has helped me appreciate what the best kind of evolutionary thinking can contribute to our understanding of medicine. Doves, Diplomats, and Diabetes: A Darwinian Interpretation of Type 2 Diabetes and Related Disorders by Milind Watve investigates diabetes from an evolutionary perspective, suggesting how it might have originated, why it persisted, and how it is related to survival advantages. Watve develops well-reasoned hypotheses that can be tested by examining their expected consequences. He believes it is impossible to understand metabolism without understanding behavioral ecology, and he makes a good case.
A reassessment of the evidence concerning Type II diabetes (T2D) reveals a number of paradoxes. Elevated blood glucose is the defining feature of T2D but controlling it doesn’t prevent all the complications of diabetes, and it doesn’t appear that elevated blood sugar could produce all the pathological changes of diabetes. Insulin resistance is believed to be central to a cluster of deadly diseases in humans, but in other animals it has no adverse effects on health and even increases lifespan. Studying diabetes from an evolutionary perspective can shed light on such paradoxes. (more…)
Being fat is bad except when it’s good. It’s called “the obesity paradox.” (No, that isn’t a mis-spelling for “two physicians who treat fat people.”) The adverse health effects of obesity are well established, but there are exceptions. Obesity appears to confer an advantage in certain subgroups with conditions like heart disease and diabetes.
In the News
Casual consumers of some recent media reports might interpret them as an excuse to stop trying to lose excess weight, especially if they are diabetic. Others might think we have been lied to about the dangers of the obesity epidemic. The reality is more complicated. (more…)
A number of buzz-words appear repeatedly in health claims, such as natural, antioxidants, organic, and inflammation. Inflammation has been implicated in a number of chronic diseases, including diabetes, Parkinson’s, rheumatoid arthritis, allergies, atherosclerosis, and even cancer. Inflammation has been demonized, and is usually thought of as a bad thing. But it is not all bad.
In a study in Nature Medicine in September 2011, a research group led by Dr. Umut Ozcan at Children’s Hospital Boston (a teaching hospital affiliated with Harvard Medical School) reported that two proteins activated by inflammation are crucial to maintaining normal blood sugar levels in obese and diabetic mice. This could be the beginning of a new paradigm. Ozcan says:
This finding is completely contrary to the general dogma in the diabetes field that low-grade inflammation in obesity causes insulin resistance and type 2 diabetes. For 20 years, this inflammation has been seen as detrimental, whereas it is actually beneficial.
Increasing levels of these inflammatory signals might actually be therapeutic in diabetes and obesity. On the other hand, they might worsen inflammatory diseases like asthma and rheumatoid arthritis. Ozcan’s findings are intriguing and might eventually lead to new treatments, but there are no clinical applications as yet.
I recently received an e-mail from a high school science department head who is teaching a unit on nutritional science. He asked for my opinion of a YouTube video of a lecture advocating a high saturated fat diet. The speaker is Donald W. Miller, Jr., M.D., a cardiothoracic surgeon at my alma mater, the University of Washington. My correspondent commented, “I have a feeling that there is room for some skepticism.” I agree: there’s a whole lot of room for skepticism.
An article based on that video lecture is available on Dr. Miller’s website. It’s entitled “Enjoy Saturated Fats, They’re Good for You!” If you want to judge for yourselves, I recommend the article over the video, as he is a poor public speaker.
Dr. Miller’s website contains a lot of disturbing material. He appears to be a contrarian who disagrees with the consensus of scientific experts on a wide variety of topics, for instance:
- Health Benefits of a Low-Carbohydrate, High-Saturated Fat Diet
- Fighting Fluoride [fluoride is poison!]
- Cardiac Surgeon Dr. Donald Miller Tells Dr. Dean Ornish to Take a Hike
- Avoid Flu Shot, Take Vitamin D [flu is a Vitamin D deficiency disease?]
- Questioning HIV/AIDS, Human-Caused Global Warming, and other Orthodoxies in the Biomedical Sciences
- A User-Friendly Vaccination Schedule [no vaccinations before age 2, no live vaccines, etc.]
He refers to questionable sources of information like the Weston Price Foundation and the notorious AIDS denialist Peter Duesberg. (more…)
Determining the net health effects of independent factors can be tricky, especially when those factors cannot be controlled for in experimental studies. For things like body mass index (BMI) we must rely on observational data and triangulate with multiple studies to isolate the contributions from BMI. But it can be done.
The data, however, are likely to be complex and noisy, and therefore there is plenty of opportunity for ideology to trump objectivity in interpreting the data. There are those who, for whatever reason, deny that we are having an obesity epidemic in the West, and those who deny the health implications of being overweight as an independent factor.
The terms overweight and obesity have had various definitions in the past, but in recent years the various health organizations have settled on consensus operational definitions (for obvious practical reasons). Their definition relates to body mass index, which is a person’s weight in kilograms (kg) divided by their height in meters (m) squared.
Journalist Gary Taubes created a stir in 2007 with his impressive but daunting 640-page tome Good Calories, Bad Calories. Now he has written a shorter, more accessible book Why We Get Fat: And What to Do About It to take his message to a wider audience. His basic thesis is that:
- The calories-in/calories-out model is wrong.
- Carbohydrates are the cause of obesity and are also important causes of heart disease, type 2 diabetes, cancer, Alzheimer’s, and most of the so-called diseases of civilization.
- A low-fat diet is not healthy.
- A low-carb diet is essential both for weight loss and for health.
- Dieters can satisfy their hunger pangs and eat as much as they want and still lose weight as long as they restrict carbohydrates.
He supports his thesis with data from the scientific literature and with persuasive theoretical arguments about insulin, blood sugar levels, glycemic index, insulin resistance, fat storage, inflammation, the metabolic syndrome, and other details of metabolism. Many readers will come away convinced that all we need to do to eliminate obesity, heart disease and many other diseases is to get people to limit carbohydrates in their diet. I’m not convinced, because I can see some flaws in his reasoning. (more…)
It seems that for every established science there is an ideological group who is motivated to deny it. Denialism is a thriving pseudoscience and affects any issue with the slightest political or social implications. Sometimes, even easily verifiable facts can be denied, as people seem willing to make up their own facts as needed.
Denialists have an easy job – to spread doubt and confusion. It is far easier to muddy the waters with subtle distortions and logical fallacies than it is to set the record straight. Even when every bit of misinformation is countered, the general public is often left with the sense that the topic is controversial or uncertain. If denial is in line with a group’s ideology, then even the suggestion of doubt may be enough to reject solid science.
We see this when it comes to the effectiveness of vaccines, the evolution of life on earth, and anthropogenic global warming. A recent Pew poll shows that the campaign of global warming denial has been fairly successful – while the science becomes more solid around the consensus that the earth is warming and humans are contributing to this, the public is becoming less convinced.
The American Society of Bariatric Physicians recently invited me to speak at their continuing medical education (CME) conference on obesity in Seattle. They got my name from Stephen Barrett of Quackwatch and asked if I could speak about questionable weight loss treatments like HGH, MIC (methionine, inositol and choline), and the HCG Diet. I seized the opportunity to discuss how to evaluate any medical claim, with examples from alternative medicine as well as from weight loss. My title was “Questionable Evidence for Questionable Treatments.” I talked about some of the things that can go wrong in clinical trials and why simply finding reports of positive randomized controlled trials (RCT) is not enough. I advocated rigorously science-based medicine and recommended the SBM website.
Several people came up afterwards to express their thanks and their agreement, but some of the questions from the audience were rather hostile. One man said he was a military doctor and he was using and teaching acupuncture (which I had criticized as a bad example of “tooth fairy science” in my talk). I asked for his opinion of battlefield acupuncture and he just said “No comment.” A couple of people thought science wasn’t enough and thought it was okay to prescribe questionable treatments when there was no proven effective treatment. I responded that I had no objection as long as the patient was told the facts and not given the false impression that the questionable treatment had been tested and shown to work.
I was glad for the chance to meet some of the ASBP members. I had never met a bariatric physician and was interested to learn about their practices and philosophies. I had never really thought about the fact that most obese patients had associated diseases like hypertension and diabetes, so their overall management could be very complex. I attended the whole obesity course: some of what I heard was educational, some of it was questionable, and some of it was frankly disturbing. (more…)