Does Diet Soda Cause Weight Gain?

Tricia Christensen
Tricia Christensen

For all the dieters out there, there are several studies that posit the question: Does diet soda cause weight gain? The answer to this is a bit complicated, but generally it can be stated that diet soda drinkers may indeed gain weight. This doesn’t mean you can answer the question with an immediate yes, but there is certainly a correlation between consumption of diet drinks and greater risk for obesity.

A bottle of soda.
A bottle of soda.

If you maintain a healthy diet, then drinking diet soda is unlikely to cause you to gain wait. If you use diet drinks to compensate for eating higher calories and unhealthful foods, drinking them might cause you to gain wait. Studies show that people often use the consumption of diet soda to justify eating any other foods, thinking that lack of calories in the soda will make up for excess calorie consumption in other foods.

Gaining weight from drinking diet soda is a possibility.
Gaining weight from drinking diet soda is a possibility.

In fact, studies show all types of diet soda cause weight gain at a higher rate than drinking soda with sugar. But again, "cause" is used loosely here, and must be considered correlation rather than cause. A 2005 study conducted by Sharon Fowler found the following facts to be true. Drinking one half to a can of diet soda daily increased risk for obesity by 37.5%. In contrast, drinking the same amount of regular soda increased risk for obesity by 30%. The greatest difference in numbers was found when people consumed one to two cans of regular or diet soda daily. Those who drank regular soda were about 32.8% more likely to become obese, but those who drank diet soda were about 54.5% more likely to become obese.

People who drink diet soda may consume more calories elsewhere.
People who drink diet soda may consume more calories elsewhere.

Experts believe that it’s not that types of diet soda cause weight gain, but instead that people who drink diet soda may be less likely to pay attention to what else they’re eating. They may even use drinking diet soda as an excuse to consume more calories. Many studies on nutrition suggest that numerous Americans are likely to underestimate their daily calorie consumption significantly.

Those who consume lots of sugary soda may be able to lose weight by switching to diet soda.
Those who consume lots of sugary soda may be able to lose weight by switching to diet soda.

On the other hand, people who consume lots of sugary soda may, if dieting, find they will lose a little weight if they switch to diet soda. Still, consumption should remain low and people should keep in touch with the other things they’re eating and have a healthy diet and exercise program.

Some researchers speculate that people who drink lots of diet soda tend to have poor diets, which can lead to obesity.
Some researchers speculate that people who drink lots of diet soda tend to have poor diets, which can lead to obesity.
Tricia Christensen
Tricia Christensen

Tricia has a Literature degree from Sonoma State University and has been a frequent wiseGEEK contributor for many years. She is especially passionate about reading and writing, although her other interests include medicine, art, film, history, politics, ethics, and religion. Tricia lives in Northern California and is currently working on her first novel.

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Discussion Comments


anon164628, that's really well put! The analogy is easy to follow and also accounts for some of the facts about how diet sodas (and some other "diet" foods) lead to weight gain.


Perhaps you can look at it this way. Call it the theory of the thyroid.

The body "sees" how many calories it intakes and sets some aside for instant energy (blood sugar), some for storage, and some for waste, and the thyroid makes these decisions.

For the sake of argument, let's say it puts calories into savings first. That means, if you drink water and eat 1,000 calories (this is just an example to show you what I mean), it puts 333 into storage, then 333 into energy, and eliminates the remaining 334.

Now, enter diet drinks, artificial sweeteners, and anything that seems like it should have more calories than it does. Say you drink a lot of diet drinks that would equal 400 calories of regular drink. Now, your body thinks it took in 1,400 calories, so it takes the first third, 466 calories and stores it, used 466 for energy and eliminates the rest.

Wait, you say. I only really had 1,000. That's right. Now, you've stored an extra 133 calories, and have 133 calories more than you need in blood sugar (energy) while eliminating only 67 or so calories. Those 133 energy calories aren't used so they'll get stored eventually which ups your "savings" by 266 over just drinking the water.

So, the zero calorie soft drink faked your taste buds into thinking it was sweet and faked your body into storing 266 extra calories! So, while it warrants an actual study, I suspect that what you consume can be well more than simply it's caloric count! That's my theory and I'm sticking to it. --Ty


I stopped drinking diet coke a month and a half ago, and ate normally (I have lost a lot of cravings) and already lost 10 lbs!


So from what I gathered from that article, is that people that put on weight from diet coke only do so because they eat too much because they feel they can because they have had a diet coke rather than full fat. So in effect the diet coke itself is not putting the weight on, as it is only 1 calorie. Is this correct?


I am a Diet Coke addict, although I've started to limit it more lately. I drink about three to five cans a day. (More on the weekends than during the week). I recently lost 14 pounds. I wasn't heavy to start with but did it more for myself to get back to more comfortable weight.

A person who drinks diet soda, eats healthy and exercises doesn't seem to fall into this category. From this article, I take it more as the people who say, "I can have this burger and fries because I'm drinking diet," well, no, you cannot.

In combination with healthy eating, I don't think this applies so much.


I suspect I know the answer but want to confirm that Crystal Light falls into the same category as "diet soda" in this discussion.


a can of diet coke and a can of light coke in front of you, which one is sweeter? which one will make you get fat?


A recent study of rats conducted by the University of Texas apparently showed that drinking diet soda might mess up your body’s ability to calculate how many Calories you've eaten and therefore cause you to eat more.... Whether the study is accepted as dispositive, who knows. But, they say that 8 fluid ounces (240 mL) of diet soda can increase your risk of becoming overweight by something like 37 percent!


so it sounds to me that drinking diet soda isn't really the actual cause of weight gain. it's more about the false sense of security drinking soda without calories gives you. i can see that, however, i'd like to hear cold, hard facts that the diet soda actually makes you gain weight. until then, i'll be sipping on my diet soda, thank you very much! ;-)

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