Could Artificial Sweeteners Be Sabotaging Your Diet?

Guest Post by Mark Hyman, MD

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. Today I will explain how that hap­pens and review some of the research that indi­cates arti­fi­cial sweet­en­ers may not be all they are cracked up to be.

The Problem with Ringing Your Physiological Bells

Ringing the bells in your body with arti­fi­cial sweet­en­ers is not a good thing. It’s even worse when you ring the bells with arti­fi­cial sweet­en­ers and then not pro­vide any sugar. Here’s why …

Our brains know how to get our bod­ies ready for food. It is called the cephalic (for “head”) phase reflex. Your brain is prepar­ing for food even before your fork or cup crosses your lips. This allows you to antic­i­pate and pre­pare for the arrival of nutri­ents in your intesti­nal tract, improves the effi­ciency of how your nutri­ents are absorbed, and min­i­mizes the degree to which food will dis­turb your nat­ural hor­monal bal­ance and cre­ate weight gain.

So, in a way, your body is already prepar­ing to reg­u­late your energy bal­ance, metab­o­lism, weight, calo­rie burn­ing, and many other things—just by think­ing about food. Any sweet taste will sig­nal your body that calo­ries are on the way and trig­ger a whole set of hor­monal and meta­bolic responses to get ready for those calories.

When you trick your body and feed it non-nutritive or non-caloric sweet­en­ers, like aspar­tame, ace­sul­fame, sac­cha­rin, sucralose, or even nat­ural sweet­en­ers like ste­via, it gets con­fused. And research sup­ports this.

Studies Show Artificial Sweeteners Lead to Weight Gain

An excit­ing study in the Journal of Behavioral Neuroscience has shown con­clu­sively that using arti­fi­cial sweet­en­ers not only does not pre­vent weight gain, but induces a whole set of phys­i­o­log­i­cal and hor­monal responses that actu­ally make you gain weight. ( i)

The researchers proved this by giv­ing two dif­fer­ent groups of rats some yogurt. One batch of yogurt was sweet­ened with sugar. The other was sweet­ened with sac­cha­rin. They found that three major things hap­pened over a very short period of time in the rats that were fed arti­fi­cially sweet­ened yogurt.

First, the researchers found that the total food eaten over 14 days dra­mat­i­cally increased in the arti­fi­cial sweet­ener group—meaning that the arti­fi­cial sweet­ener stim­u­lated their appetite and made them eat more.

Second, these rats gained a lot more weight and their body fat increased significantly.

And third (and this is very con­cern­ing) was the change in core body tem­per­a­ture of the rats fed the arti­fi­cial sweet­en­ers. Their core body tem­per­a­ture decreased, mean­ing their metab­o­lism slowed down.

So not only did the rats eat more, gain more weight, and have more body fat, but they actu­ally low­ered their core body tem­per­a­ture and slowed their metab­o­lism. As I have said many times before, all calo­ries are not cre­ated equal …

The most astound­ing find­ing in the study was that even though the rats that ate the saccharin-sweetened yogurt con­sumed fewer calo­ries over­all than the rats that ate the sugar-sweetened yogurt, they gained more weight and body fat.

These find­ings turn the con­ven­tional view that peo­ple will con­sume fewer calo­ries by drink­ing arti­fi­cially sweet­ened drinks or eat­ing arti­fi­cially sweet­ened foods on its head. Despite their name, these are not “diet” drinks. They are actu­ally “weight gain” drinks!

We’re sur­rounded by low-calorie, “health con­scious foods” and diet soft drinks that con­tain sweet­en­ers. As a result, the num­ber of Americans who con­sume prod­ucts that con­tain sugar-free sweet­en­ers grew from 70 mil­lion in 1987 to 160 mil­lion in 2000.

At the same time, the inci­dence of obe­sity in the United States has dou­bled from 15 per­cent to 30 per­cent across all age groups, eth­nic groups, and social strata. And the num­ber of over­weight Americans has increased from about 30 per­cent to over 65 per­cent of the pop­u­la­tion. The fastest grow­ing obese pop­u­la­tion is children.

Here’s the bot­tom line: Avoid arti­fi­cial sweet­en­ers, includ­ing aspar­tame, ace­sul­fame, sucralose, sugar alco­hols such as mal­i­tol and xyl­i­tol (pretty much any­thing that ends in “ol”), as well as nat­ural arti­fi­cial sweet­en­ers like stevia.

Stop con­fus­ing your body. If you have a desire for some­thing sweet have a lit­tle sugar, but stay away from “fake” foods. Eating a whole-foods diet that has a low-glycemic load and is rich in phy­tonu­tri­ents and indulging in a few real sweet treats once in a while is a bet­ter alter­na­tive than trick­ing your body with arti­fi­cial sweeteners—which leads to wide scale meta­bolic rebel­lion and obesity.

So, put that tea­spoon of sugar in your tea and enjoy!

Now I’d like to hear from you…

Do you use arti­fi­cially sweet­ened products?

How have they affected your weight?

What sweet treats do you indulge in?

Has this find­ing taken you by surprise?

Please leave your thoughts by adding a com­ment below—but remem­ber, we can’t offer per­sonal med­ical advice online, so be sure to limit your com­ments to those about tak­ing back our health!

To your good health,

Mark Hyman, MD

Mark Hyman, MD

Dr. Hyman is ded­i­cated to iden­ti­fy­ing and address­ing the root causes of chronic ill­ness through a ground­break­ing whole-systems med­i­cine approach called Functional Medicine. He is a fam­ily physi­cian, a four-time New York Times best­selling author, and an inter­na­tional leader in his field.