The Correlation

Trash Talk About Causality, Personality, and Obesity

Causality captivates people when the subject is obesity. The appetite for understanding factors that cause obesity grows more insatiable as its health and economic impact grows more devastating. That appetite surely spurred a new publication in the International Journal of Environmental Research and Public Health. Gulay Avsar and colleagues developed a random effects model to identify factors that influence the risk of overweight and obesity in Australia. They find a correlation between obesity and personality and conclude:

Policies which concentrate on lifestyle choice and economic and social factors may be inefficient if the
relationship between obesity and personality is ignored.

Cheese and Bedsheet DeathsRooting about in large datasets for correlations can be entertaining. For example, cheese consumption appears to correlate with death by entanglement in bedsheets. Absent a great deal more research, though, such correlations are a lousy basis for making policy. Correlation does not establish causality. So, no, obesity policies do not need to be based on personalities in Australia. Nor anywhere else for that matter.

Fortunately, others in Australia are putting together more robust ideas. In the Medical Journal of Australia, editor Nicholas Talley describes a six-point plan for action recommended by the Council of Presidents of Medical Colleges. Their six points are a good start for any policymakers seeking a way forward:

♦ Addressing obesity as a chronic disease, not a lifestyle choice

♦ Education and upskilling for health professionals

♦ Health professionals leading by example

♦ Pre-conception planning

♦ Evidence-based national obesity prevention strategy

♦ Stronger voluntary regulation and new legislation

These recommendations and the thinking behind them are impressive. Speculation about obesity, personality, and causality, not so much.

Click here for the study in IJERPH and here for the editorial in the Medical Journal of Australia.

The Correlation, photograph © Pascal Böhme / flickr

Subscribe by email to follow the accumulating evidence and observations that shape our view of health, obesity, and policy.


February 15, 2017

2 Responses to “Trash Talk About Causality, Personality, and Obesity”

  1. February 15, 2017 at 10:02 am, David Brown said:

    Excerpt from the “Medical Journal of Australia” editorial. “Environment is key to the development of obesity, as genes cannot account for the rapidly changing epidemiology.9 Moreover, there is evidence that the food industry has been a major contributor to obesity globally. Changes in diet are established to alter the intestinal microbiome and may lead to altered nutrient absorption as well as low-grade inflammation with immune activation potentially promoting fat accumulation, perhaps via epigenetic changes, which may in part explain why maternal obesity is a risk factor.”

    I don’t know about Australia but the United States has problems with animal obesity. For example, one can Google murine, canine, feline, equine, primate, and elephantine in conjunction with the term obesity to access articles. Excerpt:

    “We already know that most of the major health problems for humans – heart disease, many cancers, diabetes, arthritis, etc. – are the product of an unhealthy lifestyle. The same is true for elephants at zoos. And a new study, commissioned by a zoo, concludes that unless radical action is taken, the situation is so dire that elephants will be extinct at zoos within a few decades.”

    This suggests that something we’re feeding ourselves and our animals is deranging the appetite control mechanism. Excerpt:

    “…injection of either anandamide into the VMH, or that of THC into the PVN, causes a significant increase in food intake in satiated animals.

    The body makes anandamide from arachidonic acid (AA). Excerpt:

    “Current dietary guidelines recommend a shift away from animal-derived fats in favour of plant fats, in an effort to reduce saturated fat intake and cardiovascular disease risk, which has resulted in an increased intake of polyunsaturated fatty acids (PUFA), especially that of linoleic acid. Linoleic acid is easily converted by the human body to AA via γ-linoleic acid and eicosatetraenoic acid, a pathway dependent on the actions of two desaturases and one elongase. AA can then be converted to AEA via several pathways…”

    Arachidonic acid is also found in lean meat. Excerpts:

    “Results from previous studies have shown that AA is concentrated in the membrane phospholipids of lean meats… The visible fat of meat contained a significant quantity of AA, ranging from 20 to 180 mg/100 g fat, whereas the AA content of the lean portion of meat was lower, ranging from 30 to 99 mg/100 g lean meat. Beef and lamb meats contained lower levels of AA in both the visible fat and lean portion than that from the other species. (Note that sheep and cattle, being ruminant animals, biohydrogenate unsaturated fatty acids in linoleic acid-rich feed to saturated fats. Consequently, the arachidonic content of beef, mutton, and dairy is fairly low.”

    “The highest level of AA in lean meat was in duck (99 mg/100 g), whereas pork fat had the highest concentration for the visible fats (180 mg/100 g). The lean portions of beef and lamb contained the higher levels of n-3 polyunsaturated fatty acids (PUFA) compared with white meats which were high in AA and low in n-3 PUFA. The present data indicate that the visible meat fat can make a contribution to dietary intake of AA, particularly for consumers with high intakes of fat from pork or poultry meat.”

    Gorilla obesity used to be a problem in American zoos. The problem was solved by doing away with primate biscuits which contained both sugar and soybean oil. Excerpt:

    “Results of the biscuit-free diet change revealed a reduction, and in some cases elimination, of regurgitation and reingestion behavior (R/R) and a significant reduction of hair-plucking behavior. An increase in feeding/foraging was observed, although overall gorilla activity levels were not consistently increased with this diet change.”

  2. February 16, 2017 at 10:12 am, Allen Browne said:

    Yup – Talley’s six point plan for action should be considered.