Desires: inborn or learned?

A while back I realized that unless I ate some kind of sugar during a meal, I didn't feel full afterward.  Most often it was fruit, which seemed ok because the old food pyramid suggested 2-3 servings per day.  But I felt wary about the need to do it, the compulsion.  At the same time my brother Wade was on a diet that required cutting out all sugar, so I wondered if it was healthy for me to be eating it as often as I was.

I decided to start leaving sugar out of every other meal just to see how it felt.  Under-eating is a risky business for me because I get migraines if I'm hungry for too long, so at first I was little nervous.  What I immediately found was how hard it was to abstain.  Even though I was eating a large, full meal with plenty of complex carbohydrates, that desire for something sweet was strong and I had to fight it off.  But I didn't get any headaches so I felt it was worth pursuing.

After a couple of weeks I found myself wanting sugar less.  It still tasted good and I still ate plenty of fruit and the occasional dessert, but the expectation of having it be part of every eating experience had subsided.  What surprised me about this was that I had always thought that this specific desire was inherent, somehow coded into my DNA and a normal part of being a human.  Clearly it wasn't: it was buttressed up, inflated by my behavior.

Every desire fits into one of those two categories: inborn or learned.  And I think that more of them are learned.  But it can be so easy to think something has always been a part of you if your behavior has always enforced it.  Take the need for sugar; I'm sure that many of us have eaten sugar constantly almost since birth.  If the first thing in your toddler-age sippy-cup was juice, then you wouldn't be able to remember a time without that sweet substance coursing through your bloodstream.  With no sugar-free period as a comparison, how can you tell that the desire was inborn instead of learned?  Using the scientist parlance, there was no control group in that experiment.

We all have things about ourselves that we wish were different.  A negative thought process, a bad habit, an addiction.  But many people give up on trying to change with the defense, "it's just who I am."  Sometimes I'm sure that's true.  Genes are a powerful force in determining who we are.  But I think most of our desires come from the constant stream of small, simple choices that we make usually without thought.  The only way to tell the difference is to change your behavior long enough until it forms a habit and see how you feel.  I think we will all be surprised by how much is within our control.