Another reader—Dr. Benjamin Rusak, director of the Chronobiology and Sleep Program at Dalhousie University—adds another theory to the previous ones:
Olga Khazan’s article about Dr. Kuk’s research was quite interesting, and she touched on a number of factors that might account for the differences in body weight. What she failed to mention, however, is that there is a wealth of data collected over the last 15+ years demonstrating that short sleep durations, especially chronic short sleep, leads to dramatic metabolic changes. These include increases in body weight, changes in glucose metabolism, and increases in insulin resistance, similar to changes seen in a pre-diabetic state. The best estimates are that from 1960 to 2000 the average nightly sleep duration of American adults went from 8.5 hours to 6.8 hours. I’m sure that is also a large contributing factor.
If you have anything to add, especially if you have expertise like Dr. Rusak’s, drop me an email. Update from another expert in the inbox, Navin Verma, MD FAASM (Fellow American Academy Sleep Medicine):
I am a sleep physician and neurologist practicing in the Orlando, FL. Regarding obesity and sleep, this has been well documented to be an issue in children. For example, this NCBI article looked at 25 studies. All 25 studies suggested that short sleep duration is significantly associated with an increased risk of being overweight and obesity.
Another doctor in the inbox articulates similar points raised in Olga’s piece:
Since the 1950s, it is well documented that physicians over prescribe antibiotics. Medication is sure to affect our gut microbe diversity killing some good microbes along with the bad ones, especially the microbes that help us digests sugars. When our gut can no longer help to digest the sugar we consume, it places an increasing burden on our pancreas. Given the amount of sugar in the typical American diet, we may be overworking our pancreas to the point of developing Type II diabetes.
Antibiotics also play a significant role in obesity, but by a second and more insidious route than medical prescriptions. The vast majority of the beef, pork, and chicken consumed in the US is loaded with antibiotics from birth. FDA statistics show that livestock are the largest consumers of antibiotics. Why? Originally farmers wanted to reduce the spread of disease when livestock are raised more cheaply shoulder-to-shoulder vs free-range. Soon meat producers discovered another reason to infuse their herds and flocks with antibiotics; it makes them fatter faster. How much of those antibiotics in our food chain wind up in our digestive system is yet unclear. But like our livestock, we too are getting fatter faster.
For some reason, the medical field has refrained from connecting the dots for the popular press as I have done, even though there is ample evidence for what I have said. Part of the problem is over-reliance on long-term controlled epidemiological studies. But some have been done by Tim Spector and others. Look how much data accumulated for decades about the health effects of tobacco smoking before Dr. Koop connected the dots for the public and stood up to the lobbyists.
Needless to say, the agribusiness and pharmaceutical fields can bring to bear far more lobbying resources than tobacco could ever do in order to keep dots from being connected.