There’s no doubt about it.

Artificial sweeteners cause obesity.

I always thought it was funny to see a very large person order a Big Mac, large fries -- and top it off with a Diet Coke. I also found it peculiar that I rarely saw thin people drinking diet sodas.

So I began to wonder if there could be a link between diet beverages or artificial sweeteners and obesity.

As I began to explore this notion, I discovered a number of different research findings that pointed to this very phenomenon.

First, our current obesity epidemic has coincided perfectly with the introduction of large amounts of artificial sweeteners into our food supply. Although we cannot say for sure that this means artificial sweeteners cause obesity, it certainly makes me wonder.

Next, a body of research indicates that just the thought or smell of food initiates a whole set of hormonal and physiologic responses that get the body ready for food.

This is familiar to us from Pavlov’s dog experiment, where he trained dogs to salivate by associating the ringing of a bell with the presentation of food. By doing this repeatedly, he eventually trained the dogs to salivate in anticipation of food simply by ringing the bell -- without any food at all.

Think of diet sodas and artificial sweeteners as ringing the bell for your physiology.

But why is that bad? And why is it even worse to ring the bell with artificial sweeteners and then not provide any sugar along with the bell?

What happens to the body?