Punch #1: Bigger is Better
Studies have shown that, when given a choice, birds will preferentially sit on the bigger of two eggs. Why? Bigger eggs have more nutrients to nurture the embryo so, when it hatches, it is more mature – and is more likely to survive. Makes perfect sense – unless you introduce an egg that is outside of their evolutionary reality: Give them a giant egg (i.e., of another species) and they will ignore their offspring to sit on it. Obviously, in this case, their hardwiring produces the wrong response. For good nutritional reasons, we are conditioned to seek out bigger fruits, plumper prey, rounder melons, and brighter colors.
Supersize Me
In study after study we find that people will chose larger portions (in some studies, up to 90% of us will) and will eat more, if given a choice between ‘regular’ and ‘super-sized’. Even if we don’t eat all of a larger portion, we eat a minimum of 30% more just by virtue of being offered a larger portion. Other studies show that, even before deciding to eat, larger is more appealing: we salivate more, pay more attention to and are willing to work harder for ‘big’ things – including cups, plates and packages – even bigger pictures get us more excited.
Punch #2: Too Much Is Never Enough
All higher order animals have some type of built-in mechanism that regulates caloric intake relative to activity and other energy needs. However, in some cases, our evolutionary reality never provided an opportunity for “too much” of some nutrients. There simply was no need to hard wire an upper limit on things like salt, sugar and fat – because the foods available to us (or the energy required to get them) meant that, in practical terms, we could never get enough.
The Land of Plenty
It is estimated that, during most of our 200,000 year developmental history, we expended significantly more than 2/3rds of our resources on feeding ourselves. At the time of the Civil War it still took 80% of the population to feed us. Today less that 3% of us are actively involved in primary food production.
On the other hand, the 3% of us that are farming allow us all to consume over 1/3 lb of pure fat, per person, per DAY (soybean, corn and animal) – and the demand has jumped 15% in the last 15 years.
At the time of Caesar, salt was scarce enough to be used as a currency (the English words salt and salary both come from the Latin root sal, or salt.) Today it is estimated that we have enough readily available salt around and under the Great Lakes to allow unbridled consumption for at least the next 70 million years.
Before Columbus introduced Europeans to sugar, normal foods simply were not sweet. Even at that, ‘sweet’ was the exclusive parlance of the aristocracy, who would sometimes consume up to 4 lbs. of sugar in a year. It was considered a ‘fine spice’ and used sparingly. For American settlers, ‘sweet’ came from apples and sweet potatoes. Honey was the only ‘sweetener’ for most of our history. Fast forward: Last year (USDA) we consumed 156 lbs. of sugar per person.
Obsolete Hard Wiring
Until relatively recently, it was virtually impossible to get too much fat, salt or sugar. Our brains developed ways to motivate us to find these scarce nutrients (dopamine) and enjoy them (endorphins), but had no reason to develop a mechanism for stopping us.
Combine our innate drive to find as much fat, salt and sweet as possible with our conditioned preference for bigger – with the fact that all three are cheap and incredibly available – AND with the realization that we have never before needed an ‘off’ switch - it is no wonder that the hardwiring that served us so well has not only up and left us flat – it has left us fat.
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