Evolution made you a misanthrope :)

Well that’s a strange title.. but let me explain 😉

Evolution of Immunity

Evolutionary approach to studying human behavior is focused on the adaptive value of the behavior… so we are asking questions like “why has X behavior evolved and what costs and benefits it brings?” When our sensory system (vision, smell…) is faced with a disease-connoting cues (e.g. a sick person), two defensive systems get activated:

The immune system
The behavioral immune system

Mounting an immune response in the body is quite costly in terms of energy spent and it is required only after the body has contacted pathogens.. but the behavioral immune system activates our basic emotions (fear, disgust) and behaviors that prevent contact with potentially dangerous objects (in terms of transmitting disease), so saving our body precious energy needed for the actual physiological immune response 😉

This behavioral immune system is trying to be over-careful, though, and will react not only to actual disease-reminding stimuli, but also to stimuli that resembles signs of disease (but may not logically be dangerous- like a sterilized glass that used to have a roach in it… there glass is perfectly clean but people are still disgusted when drinking from it… or a person with a disability- they’re not actually contagious).

So, first of all, what does this have to do with being a misanthrope?

Well, this emotional response to things that are dangerous to health (whether truly or only perceived..) is stronger in people who think themselves vulnerable to disease. Such people show a HIGHER level of an averse response to:

  • physically disabled people (Park et al. 2003)*
  • older adults (Duncan&Schaller, 2009)
  • Immigrants (Faulkner etal. 2004)
  • obese people (Park, Schaller & Crandall, 2007)
  • some animals (Prokop et al. 2010)
I know these are not roaches..just chocolate (which i adore), yet i can’t imagine even touching these without disgust

Being open to new experiences and being an extrovert is associated with larger social networks (having more friends&acquaintances), but ALSO with higher risk of being infected by pathogens (the more folks you get in contact to, the more changes to catch something). Again, a stronger negative response is seen in those that perceive themselves to be more vulnerable or come from areas with high pathogenic load (=lots of diseases). So if you’re not a people person, there’s nothing particularly “abnormal” about you.. Indeed, you are quite a well-adapted fellow 😀

And second- what does this have to do with food??

Usually everything I post has something to do with health and diet.. so I need to make a connection here. Researchers hypothesized that, similarly to the behavioral avoidance of disfigured people triggered by this over-protective emotional immunity, new technologies might activate behavioral avoidance. New technology like genetic modification or highly processed foods in general.

Researchers decided to see if they can predict attitudes toward GMOs by people with different levels of pathogen sensitivity. And they did find that people who felt themselves more vulnerable to infectious diseases had significantly more negative attitudes toward GM products (Prokop et al., 2013). Of course, there are many many reasons people do not like GMOs- rational and emotional, but this is a pretty cool finding nevertheless.

So, many things about us and our personality might be an important adaptive response.. does not mean we can not override these “instincts” with some logic (e.g. knowing obese individuals are not in any way going to make you sick thus not stigmatizing them).

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GET MOVING!…?

While my main focus is on nutrition and health, I do keep in mind that the best companion of good eating is staying “active”! Unfortunately I am not a fan of long hikes and running marathons, yet my activity hobbies (whether zumba, swimming, or yoga) are continuous and keep me moving. Personally, I think it is unwise to focus either on food or physical activity solely (I believe food can lead specifically to stronger body weight management outcomes than activity, but we shall discuss it later), but luckily taking care of one usually results in improvement in both (from what I have observed).

Sit down & Relax

Currently, public health recommendations encourage people to engage in   30 min per day or 150 min per week of moderate-to-vigorous activity, and this represents only 3% of the time we spend awake. That is really not that much, and indeed used to be very easy to achieve without any conscious effort.

However, more&more studies on the issue of sedentary behavior (TV watching, dissertation writing 0_0) are emerging and might need their own recommendations. There is evidence that sedentary behavior has a negative independent effect on health (so, you might be going to the gym 5 times a week, but if you are sitting most of the rest of your time this leads to poor health regardless of all that gym time).

Definition: The term sedentary behavior (from the Latin word sedere, “to sit”) describes a distinct class of activities that require low levels of energy expenditure in the range of 1.0–1.5 METs (multiples of the basal metabolic rate) and involve sitting during commuting, in the workplace and the domestic environment, and during leisure.

Unfortunately, being sedentary is as natural as it gets these days- I, for instance, drive to campus and spend hours sitting in classes or in my office working on research.. I try to take a break to walk around, I try to go to the gym..but that might not mitigate the 5+ hours I have to spend simply SITTING :/. [and I am typing this from a library, where I plan to spend most of my Sunday..]

Currently, optimal levels of sedentary behavior to recommend the public are not known.

Not too many methodologically-strong studies are available yet, but time spent in sedentary behavior has been shown to be consistently associated with increased risk for all-cause, CVD-related, and all-other-causes mortality in both men&women independent of body mass index and physical activity. (caution: still only 6 studies to date)

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