Diet Drinks Confuse the Brain

July 14, 2012

Diet Drinks Confuse the Brain 

 Reference: Science News,  July 14th, 2012  Physiology and Behavior 

 Another nail in the coffin of, “A calorie is just a calorie”!   If that were the case, this study wouldn’t be true.  Our bodies are incredibly complicated organisms with all sorts of feedback loops that we mess with when we try to manipulate them.  That’s what we try to do when we drink diet soda.  We think it’s zero-calorie so it must be better for us.  We won’t gobble down so many calories that way. What we don’t realize is that we still have the flavor sweet in our diet soda.  Whether it be saccharin, as in this study, or any other artificial sweetener.  And in response to that flavor called sweet, we put out insulin and all the other hormonal adjustments that we anticipate for the arrival of those calories, a few seconds or minutes later.  

What Erin Green and Claire Murphy did, and will be publishing in Physiology and Behavior, was to try and understand what happens to your brain response pattern by studying it directly with brain scans, while giving healthy young volunteers a slight taste of saccharin in their mouths.  They had two groups of subjects: one group was steady diet soda drinkers. The other group were non-drinkers.  Each group had markedly different areas of their brains light up in response to the flavor sweet (from saccharin).  

Compared to the non-drinking group, the regular diet soda group had the area of their brain that is reward processing strongly downregulated, to both saccharin and sugar.   In particular, they noted a reduced activation in the caudate head, which is the area that is associated with rewards and food motivation.  That reduction has been linked to obesity. What this means is simple and elegant.  Your brain responds to the delivery of calories before the calories make it into your system.  You start to anticipate the arrival of the calories by putting out hormonal responses, just with the taste.  In fact, you start with just the thought, but that’s for another day.  

If you are putting out hormones, you expect to get the calories. When the calories don’t arrive, you have a mismatch, so have to adjust your “response meter”.  The next time you have that flavor, you assume no calories are coming.  Then you overstep.  Your brain gets faked out and all confused.  No wonder we gain weight when we use artificial sweeteners. What this study confirms, to my eyes, is the continuing theme that every calorie we eat is more than just a calorie.  It also represents the initiation of a hormonal response.  The food we eat isn’t just calories but a complex set of messages.  Those messages are as important as the calories.  This explains a lot of confusion when fully understood. 

 WWW. What Will Work for Me.  The tangled web of calories versus messages and hormonal effects feels overwhelming.  It’s gradually sorting out, much to my relief.  If it’s sweet, I’m dabbling in trouble.  I keep trying to find comfort in other flavors.  Lemon has been high on the list recently.  With summer, sweet basil is up there too. Written by John E Whitcomb, MD   Brookfield Longevity and Healthy Living Clinic, 262-784-5300  or Archives at

Written by John E Whitcomb, MD Brookfield Longevity and Healthy Living Clinic 17585 W North Ave, Suite 160, Brookfield, WI 53045 262-784-5300 Archives at