The Trouble With The Science Of Healthy Living

We got every possible vaccination for our children. I get a flu shot every year. I almost always favor allopathic medicine (the kind M.D.'s practice) over the various "holistic" alternatives (e.g. over osteopathic medicine, herbal remedies, faith healing, homeopathy, chiropractic, acupuncture, etc.).

Bad, Evidence Based Nutrition Advice

But, some of the biggest, supposedly evidence based health recommendations of my lifetime have turned out to be unsupported as past evidence was critically reviewed and new evidence was gathered.

* The recommendation of a low fat diet has been almost universally discarded in the weight loss field in favor of diets that are low carb and high in green vegetables, mostly because few people can keep to a low fat diet and loss weight on a sustained basis, while many people can lose weight on a diet that focuses on lower carbs and relatively more proteins. The recommendation was based on low protein, high carb (on a percentage basis) diets in places like Japan during periods of dietary scarcity and accompanied by more physical activity, that didn't translate well to Americans.

Several recent systemic reviews show that high-fat diets produce greater weight loss than low-fat diets, when both groups in the trials are given equivalent support. 

Most importantly, reducing fat intake did not lower rates of cardiovascular disease in two major clinical trials, Look Ahead and Women's Health Initiative, whereas increasing fat intake in the Predimed Mediterranean diet study did. Consistent with these findings, a study this year found that people consuming a high-fat diet had 16% lower rates of premature death than those consuming a low-fat diet (although the type of fats played a significant role in determining risk). 

Responding to new evidence, the 2015 USDA Dietary Guidelines lifted the limit on dietary fat, unofficially ending the low-fat diet era.

* The recommendation of a low salt diet has been largely discredited.

* The recommendation of moderate alcohol consumption with a very large effect size (a reduction in cardiovascular disease by something on the order of 50%), accompanied by anecdotal evidence from France (where wine consumption is high and cardiovascular disease rates seem low relative to a very rich diet) and from many people who lived very long lives with moderate alcohol consumption as a habit. 

But, it turns out that the data was skewed by the fact that in American society a lot of people who consumer no alcohol at all do so due to a prior history of alcohol abuse that they are responding to, or because they take drugs for other health problems that don't interact well with alcohol. This is the so called "sick quitter" problem. New research shows essentially that no alcohol consumption is optimal from a health perspective.

* Low does aspirin regimes also had a very large effect size (a reduction in cardiovascular disease and some cancers by something on the other of 50% in a manner potentially cumulative with moderate alcohol consumption), but while this does have a powerful effect in people who are actually diagnosed with a cardiovascular disease, it is harmful in older people who have not been diagnosed with cardiovascular disease.

For decades, a daily dose of aspirin has been widely considered a way to protect healthy people from cardiovascular disease and even cancer. But a large international study finds that even at low doses, long-term use of aspirin may be harmful — without providing any benefit — for older people who have not already had a heart attack or stroke. 

The new research reinforces the results of a study published in late August, which found that daily low-dose aspirin was too risky to be prescribed to patients at moderate risk of heart disease. In the August study and the new one, researchers found a significant risk of internal gastric bleeding caused by the medication, which thins the blood. Older patients experienced no health benefits from taking aspirin, according to the new report, published Sunday in the New England Journal of Medicine.

Individually, these results revisions make sense. But, the initial discredited results screwed up the lives of tens of millions of people at a time over half a century or so, and seriously tarnishes the credibility of evidence based health recommendations in the process.

Finally, there is no serious doubt that sugary drinks like sodas make obesity more likely. New studies have found that diet sodas are correlated with health risks almost as great as sugary sodas. But, those studies have almost identical flaws to the moderate alcohol consumption studies. Most people drink diet sodas because they are obese after a history of drinking sugary sodas. Obesity is bad for your health. And, lots of people who drink diet sodas nonetheless fail to lose substantial weight.

The Bigger Issue

The big picture issue is that a cultural mix of diet, exercise and patterns of daily life that persisted, sometimes for centuries, has been thrown out of whack by new conditions that most people have encountered in the modern developed world and the United States, in particular.

New agricultural methods, international trade, and affluence have made foods that were previously very scarce, like refined sugars and simple carbohydrates and red meats, easy and cheap for everyone to obtain, while technologies from widespread personal automobile ownership to computers and agricultural and factory automation, with changed urban planning patterns driven by these technologies, has also produced dramatically mode sedentary lives.

Try as we might, our patterns of diet, exercise, sleep and all other aspects of daily living have fallen into disequilibrium in this period of dramatic economic and technological change. But, try as we might to seek scientific guidance and to change our lifestyles (and food and tobacco consumption statistics for the U.S. show genuine significant mass responses to the latest public health recommendations of all kinds with a decade or two lag in most cases), we still haven't struck a comprehensive balance that can become a new tradition that is part of a new globalist, modern culture.

As a result, a lot people people are overweight and a lot more people are obese and morbidly obese with associated health problems like type two diabetes, cardiovascular risks, cancer and more.

In a couple of generations, we will probably as a society, strike a new balance of daily life traditions of eating and activity and other practices that make us all healthy, but we aren't there yet, although the latest rounds of reassessed evidence bring us closer than we were fifty years ago.

Of course, it may take longer, because the situation is still in flux.

New foods (like pea based meat substitutes and lab grown meats) are being created. New lifestyles (like intermittent fasting) are developing.

Considerations like the water demands of different kinds of foods, the environmental issues associated with petroleum based fertilizers and pesticides, and with toxic pesticides, the potential issues (thus far, with worries not realized) of genetically modified (GMO) foods, and the efficiency with which different foods convert energy and other resources into food, may put economic pressures on different mixes of foods that aren't yet present. World populations are growing, although they are leveling off as countries develop. Climate change and rising fossil fuel prices in the long run could also be relevant.