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.
Stop confusing your body. If you have a desire for something sweet, have a little sugar, but stay away from “fake” foods.
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
(i) Swithers SE, Davidson TL. A role for sweet taste: Calorie predictive relations in energy regulation by rats. Behav Neurosci. 2008 Feb;122(1):161-73.