How to Gain Weight on Diet Soda

Erythritol, the too-good-to-be-true nontoxic, low-calorie, tooth friendly sweetener that I profiled in my last Care2 column “Is There a Safe, Low-Calorie Sweetener?” may even act as an antioxidant. So what’s the catch?

Well, there are three ways that all low-caloric sweeteners could theoretically be harmful independent of their specific chemistry. As I report in my 2-min. video How Diet Soda Could Make Us Gain Weight, several large studies have found an association between artificial sweetener use and weight gain, meaning the people that drank the most diet soda, for example, gained the most weight. The most common explanation for this counterintuitive finding is what’s called reverse causation. People aren’t fat because they drink diet soda; they drink diet soda because they’re fat!

But there are at least three less benign alternative explanations. The first is called “overcompensation for expected caloric reduction.” If you covertly switch someone’s soda for diet soda without him or her knowing it, his or her caloric intake drops. Obviously, right? They’re not drinking all that sugar anymore. But what if you tell them what you did? People who knowingly are consuming artificial sweeteners may actually end up eating more calories. Why? Because they’re like hey, I’m drinking diet soda, so I can have two pieces of cake.

One of the studies I profile involved giving people an artificially sweetened cereal for breakfast, but only half were told. When it came to lunchtime, the group that knew they had eaten an artificially sweetened cereal ate significantly more than those that didn’t know any different. Basically, it’s the diet-soda-with-a-fast-food-meal syndrome. One may only lose weight on diet soda if you don’t realize it’s calorie-free.

The second reason even the most harmless noncaloric sweetener could still be harmful if we’re not careful has to do with how our brain is wired. Click on my video pick above to learn how the disconnect between sweetness sensations coming from our tongue and the lack of a caloric feedback loop in the gut may result in overeating.

Finally, all sweeteners–natural and artificial, caloric and non-caloric—help maintain cravings for intensely sweet foods. As I explain in my 2-min. video Unsweetening the Diet, if you go on a low salt diet, for the first few weeks everything tastes like cardboard until your taste buds have a chance to adapt to the new norm. After that, natural low sodium foods taste perfectly fine and adding table salt tastes gross because it’s way too salty. Same thing with the sweeteners.

At home maybe you use a harmless sweetener like erythritol—that’s great, but then what if you go on vacation and forget it at home? You still take your preference for severely sweet food with you and that may end up translating into the increased consumption of less than healthy foods.

So those are the caveats for even nontoxic sweeteners. They are only safe if you don’t use them as an excuse to eat more junk food.

In health,
Michael Greger, M.D.

PS: If you haven’t yet, you can subscribe to my videos for free by clicking here and watch my full 2012 presentation Uprooting the Leading Causes of Death.

Image credit: vikapproved / Flickr

Is There a Safe, Low-Calorie Sweetener?
Aspartame: Fibromyalgia & Preterm Birth
Diet vs. Exercise: What’s More Important?


William C
William Cabout a month ago


W. C
W. Cabout a year ago

Thank you.

Mac C.
mac C5 years ago

Very well explained. I don't drink diet soda, but I know others that do and will pass on. Thanks.

Patricia H.
Patricia H5 years ago

very informative

Amira R.
Amira R5 years ago

Maybe I should show the part about salt to my mom... I think she has salt with dinner, and not dinner with salt. It's crazy!

Magdalen B.
Magdalen B5 years ago

It's probably best to learn to like less sweet foods and drinks.

Heidi Aubrey
Heidi Aubrey5 years ago

Greatfully, my desire for sweet has diminished significantly as I have gotten older.

Aaron Bouchard
Aaron Bouchard5 years ago

Thanks. I don't like diet soda

rene davis
irene davis5 years ago


Ken W.
Ken W5 years ago

All soda is bad for you ----- WATER WATER WATER think about it !!!!!!!