Medieval doctors cured cancer by killing a puppy and pressing it on top of the tumor. Today, the US spends something like $90 billion per year on useless treatments for lower back pain.
It's good to know what doesn't work. In this blog post, I'll describe some examples of negative scientific results about health, diet, and exercise, and how you can make your life better by accepting them.
If you look through the literature on weight loss, what you see is mostly a proliferation of studies that measure short-term results from behavioral interventions such as restricting how many calories the subjects are allowed to eat. But, with some possible exceptions such as boxers and actors, people don't go on a strict diet with the goal of losing weight for a few months. They're hoping to make a change that will not just be a yo-yo cycle. A review of the literature (Mann 2007) shows that people almost always do regain the weight. In fact, when systematic errors are taken into account, the weight and health outcomes for people who underwent even rigorously supervised dieting are difficult to distinguish from the outcomes of people who didn't.
The first good news is that you can embrace this finding and have a better life. Nobody enjoys feeling guilty or self-conscious about eating, and the negative result of the research says that there is no need to.
According to the scientific evidence, there are also other strategies that we could focus on instead:
a new class of drugs called called GLP-1 agonists
bariatric surgery
preventing initial weight gain
Ignoring the science is particularly harmful because it reinforces negative cultural beliefs. Those beliefs cause doctors to shame their patients rather than recommending effective treatments, and influences governments not to pay for drug treatments until people already have diabetes.
When I was in high school in the 1980's, my gym teachers all made us stretch before we did any physical activity, which mostly consisted of team sports involving low-intensity running.
The evidence shows that static stretching doesn't prevent injury in this type of activity, and it also reduces performance (Baxter 2016). In fact, many of the stretches that have been traditionally taught don't even stretch the muscle that they were supposed to have been stretching. For example, the quadriceps is not actually possible to stretch.
You can get some benefits from accepting the science. Most people have a hard time fitting exercise into their daily lives, and skipping the stretch means you're eating up less of your time. If you're competitive, not stretching may even be an advantage.
Another old chestnut from my high school teachers was that you had to drink electrolytes to avoid muscle cramps. Actually, your sweat has a lower concentration of sodium than your blood, so as you sweat, it's even possible for your electrolyte concentration to go up. The best evidence suggests that cramps are actually a result of repeated stimulation of the nerves (Schwellnus 2008).
As a reward for knowing about the science, you can avoid drinking so-called sports drinks, which are a marketing phenomenon with little scientific justification. They're expensive, and they come in single-use plastic bottles, which are a huge environmental problem.
There are a lot of other examples where you can have a better life by knowing about what medical treatments are bogus. When I was a kid, we ate margarine instead of butter because it was supposed to be better for you. (Turns out that, if anything, it's the other way around.) Early treatment of prostate cancer does a huge amount of harm. Many physical therapists provide treatment with heat, cold, and ultrasound, which the evidence shows are shams. Popular wisdom about drinking water is mostly bogus, and it has even caused deaths.
I hope this article has been helpful to you. Enjoy life!
Ben Crowell, 2023 Jan. 10
This post is CC-BY-SA licensed.
Baxter et al., 2016, "Impact of stretching on the performance and injury risk of long-distance runners," https://sci-hub.se/https://doi.org/10.1080/15438627.2016.1258640
Mann et al., 2007, "Medicare's search for effective obesity treatments: diets are not the answer," https://sci-hub.se/https://doi.org/10.1037/0003-066X.62.3.220
Schwellnus et al., 2008, "Cause of Exercise Associated Muscle Cramps (EAMC) — altered neuromuscular control, dehydration or electrolyte depletion?," https://sci-hub.se/http://dx.doi.org/10.1136/bjsm.2008.050401
Tiger - Malene Thyssen, CC-BY, https://commons.wikimedia.org/wiki/File:Siberian_Tiger_by_Malene_Th.jpg
