The Standard American Diet (SAD), or Western Pattern Diet, is a recent phenomenon, born of increased industrialization that allows for nearly unlimited access to high-calorie foods with little diversity in food choices. Aspects of this diet have repeatedly been correlated with the chronic disease conditions that are so common in our culture including type 2 diabetes, heart disease, and various cancers.
The primary components of the SAD include that it is:
- Low in fiber
- High in unhealthy fats (but often low in good fats)
- High in processed foods
- Low in complex carbohydrates
- Low in plant-based foods
- Low in diversity
Essentially, the rapid rise of our technologies has outpaced our ability to adapt to them. Humans evolved over tens of thousands of years in conditions where fast food did not grow on trees, sugar was a rare treat only to be shared when someone was willing to climb a tree and raid a beehive, diets varied seasonally, and consistency in food items was rare. Oh, and we expended energy to retrieve the food.
Obviously, this is not the case today and we are seeing the consequences. It is fairly clear that consistent and abundant access to high-calorie, poor quality food combined with a lack of physical activity leads to obesity and health issues (although there are certainly other variables that have an impact).
People are very emotional about their dietary choices, and if you look around the internet, you’ll find hundreds of people touting magical claims about a wide array of different dietary options (paleo, vegan, low fat, high fat, on and on). There’s a lot of competing evidence, values, and beliefs tied into these claims. In some ways it seems that we are getting closer to ‘dietary truths’ (there is a lot of overlap that many characteristics of the SAD are not good for us), but it is very difficult to scientifically assess what a human NEEDS nutritionally and calorically to live compared to how they might THRIVE and also what best PREVENTS disease. There are just so many variables in the food itself, in the individual humans, and in the environments we live in.
Given this, I’m not sure why it came as such a surprise when I first began to realize that we don’t know much about the diets of the animals we keep in zoos. Each animal has their own unique evolutionary history that has led to their diverse (or not) food sources, ability to cope with environmental fluctuations, and foraging strategies. If we haven’t been able to understand how these variables shaped our own diets, how could we expect to know this much about the diets of the hundreds of animals we keep in captivity?
Zoos try to learn about the natural history of the animals that they keep, but there are many gaps in the scientific literature about wild animal ecology (some animals are extremely difficult to study), and there are variables that we can’t always (or are very difficult to) measure in wild animals’ dietary strategies How would we know the exact nutrient composition of their foods, caloric counts, etc.? And if we get close to finding out, how would we know that what they are eating is what is actually good for them and not just a treat they were eating during the period of our study? And then how would we account for seasonal differences, yearly differences, etc? Nature is complex! There are ways to study some of this, but it takes a great deal of time, money, and people to do the research. And so, many zoo animal diets are loosely based on research done with the closest related domestic animals – cats, dogs, horses, cows, etc. Bears eat dog food mixed with some produce; lions are fed similarly to domestic cats; zebras are fed similarly to a horse.
But many zoo animals also appear to be victims of the SAD (or their version of a diet that is not what they evolved to eat), and there is evidence that many of them are overweight. We also see a lot of health concerns arise in zoo animals that we associate with obesity in humans. As with humans, there are a lot of variables that might be accounting for this, and it is likely related to more than just diet — it could also be related to inactivity, lighting, individual differences, the list goes on…but it really started to raise a lot of ethical questions for me –both in terms of keeping all of these animals in the zoo when we don’t know how to best care for them, but also in terms of how I’m living my own life.
Seeing the animals in the zoo, the way that they are fed, the way that their dietary choices are controlled, and the lack of activity that they have in their environment was like I was staring at myself and so many other humans I know (and was tormenting me enough that I decided to leave my PhD program with a Master’s degree). In a lot of ways, industrialized societies hold us all captive. The forces that keep us captive might be different—no one keeps me confined to a single area, but there are plenty of human-created systems that do a good job of confinement instead. We’re psychologically (and often monetarily, or physically) attached to them, and it is difficult to break free. However, it is not impossible and I do believe that we can begin to make a shift in our lives where we value freedom, authenticity, and more “natural” living patterns of living as we continue to face the flaws of industrialization. This also plays in well with realizing the ways in which industrialization has created havoc on the planet, and the shifts in our behavior that will need to happen so that we can live on this Earth in a more sustainable manner…
I hope to continue on this topic further at another time (I’d actually love to write a book comparing similarities between “civilized” human behavior and health to that of zoo-housed animals), but I began this post because my thesis was recently published online, and it discusses some potential links between the diets of zoo-housed orangutans and some of their health and behavior concerns. While wild orangutans eat an extremely diverse diet of seasonally-dependent fruits, leaves, bark, insects, and even the occasional animal, their diet in the zoo is much different: they eat processed biscuits (the major ingredients of which are corn and soybeans), less fiber, and fruits & vegetables that were bred for human consumption (i.e., they’re higher in sugar and lower in fiber than most wild fruits and vegetables).
You can find the abstract for the thesis at this link, or if you really felt inclined, you could download the whole thing!
In any case, I hope that I’ve provided some food for thought, and I feel that the links between our own dietary crisis and how we feed animals in captivity deserves further attention.