Diet Sodas – Are they really bad for us?

When I undertook to lose weight, I looked at my diet quite extensively.  One item that I was over-consuming was diet soda.  Naturally, like a lot of people, I thought “well, it’s DIET soda …so it can’t be bad for you!”  However, I was aware of controversies out there and wanted to ensure I was making the best decision possible, so I looked whether or not soda is truly bad for you.

There is lot of conversation out there talking about the health impact of soda and diet soda, and whether or not it contains ingredients that are harmful.  You’ll find everything from research studies to rampant rumors that either seek to debunk or reinforce the theory that soda – particularly diet soda, is bad for you.

I heard that diet soda contains artificial sweeteners that are worse for you than sugar – so you might as well drink sugar pop!   Then I heard that sugar in soda is the leading cause of tooth decay, so I should drink diet.  Then I heard aspartame causes cancer in lab rats on the 4th moon of Saturn …on a Tuesday…but only when Saturn is at Perigee to the sun.  I think you get my point.   I was going to have to wade through a ton of chaff to get to the wheat.  Let’s look at what I found:

coke 1 hr

Sugar Sweetened Beverages

The Centers for Disease Control and Prevention has noted that sugar sweetened beverages – like soda – are the leading source of added sugars in the American diet.  Further, they note a link to weight-gain, obesity, type 2 diabetes, heart disease, kidney disease, non-alcoholic liver disease, tooth decay, cavities and gout.

Recently I wrote an article on the impact of a sugar beverage on a dime that was simply hit by a few splatters.  It was fairly stunning to see what happened and while the science is fairly simple, the combined effect with the CDC information was impactful.  So …I made the conclusion pretty quickly that sugar sweetened beverages needed to get crossed off the list.


Diet Soda

Diet soda remains a topic of hot debate.  While they don’t have sugar, they often have aspartame as the sweetener which is the source of most debate.  So I took a look at aspartame and the surrounding controversies. What I found was that there have been a metric ton of studies on Aspartame – over 100.  It’s more than the source of the debate, it’s a lightening rod!  So I sought out more information…


What is Aspartame?

Aspartame is a chemical combination of two amino acids.  It was stumbled upon during unrelated drug research.  It was approved by the FDA in 1981 and appears under brand names such as Nutrasweet and Equal. It’s about 200 times sweeter than an equivalent volume of table sugar.  What that means is it is about 200 times more potent, so you can use less. According to the FDA, Aspartame is one of the most rigorously tested food ingredients.  This doesn’t surprise me given all the controversies and reports of negative health reactions.



Originally, there were claims made that it would benefit people through weight loss and diabetes.  No study has shown that to be true.  Some studies have actually found an association with weight gain and heart disease risks.   However, most major studies have rendered verdicts that are inconclusive.  This link provides an NIH article discussing current research and some of the tests in question.

I’m going to spare all of you the science diatribe with Aspartame studies, and skip right to my conclusion.  While the science remains inconclusive, I’m suspicious.  There have been a great deal of studies that have linked Aspartame to negative health impacts but were unable to definitively draw a connection.  It doesn’t mean the connection isn’t there – it just means that within the confines of the study parameters they were unable to prove it.  So I decided that Aspartame was not going to be part of my plan going forward.

In addition, I stumbled across other information about artificial sweeteners that I found both enlightening and alarming…


Insulin Theory

There is a working theory (from a Purdue University study)  that synthetic, artificial sweeteners still trigger the brain’s sweetness receptors, and the body prepares itself for the influx of calories that come from sugar.  The pancreas creates insulin, which breaks down sugar, but when that sugar doesn’t come, the body goes searching for those calories in other foods.  The impact of this is that the cells, realizing there is no sugar to break down, become less efficient at responding to the signal to pump out more insulin.


Kindey Issues

A Harvard Medical School study that ran for 11 years and followed more than 3000 women. The researchers found that diet soda was associated with a risk of kidney decline that was twice that of patients that did not consume diet sodas.  Kidney function started declining when women drank more than two sodas a day.  Since the decline was not associated with sugar sweetened beverages, the results suggested that the diet sweeteners are responsible.  Again, not conclusive …but do we need it to be when we’re put in a position of making health decisions for ourselves?


Malfunctioning Metabolism

The Purdue study suggests a similar outcome to a University of Minnesota study from 2008 that screened 10,000 adults and found that even just one diet soda a day is linked to a 34% higher risk of metabolic syndrome.  Symptoms include belly fat and high cholesterol that puts you at risk for heart disease.  While not definitive, these studies are examples of the many indicators that suggest diet soda can be an issue for our general health.

Yes, I know I said I would skip the science schpiel.  I lied.  Also, I dare you to say “Science Schpiel” 10 times fast!  Even money says you are saying “Shyence Sheel” before 7 times!  Go on …try it.



What happened when I stopped drinking diet coke?

When I started dieting, I stopped drinking diet soda.  This was a month before I could exercise.  When I started my diet I had recently taken a fall and hurt my MCL.  That was about 5 weeks before I started my diet, and it was another 4 weeks before I could begin exercising.  Why is this important? …because it underscores that exercise did not play a part in the results I saw during the initial cessation of diet soda consumption.

In short, I had been retaining a lot more fluid in my body, particularly my legs, than was normal.  I had been living with it for so long that I had no clue that it was abnormal.  A lot of that water and inflammation went away fairly quickly.  The lynchpin element seems to be the diet soda.  As soon as that was gone, I was no longer retaining the water.


What about Sodium?

The nutrition label on a 12 ounce can of diet coke says that it contains just 40gms of sodium.  That’s 2% of our recommended daily intake. However, something was making me retain all that water.  While the amount of sodium may not be a pure trigger, perhaps in combination with the Aspartame they were more potent in this regard.

Pyure PacketsStevia as an alternative?

Stevia is a natural, no-calorie sweetener that is derived from a South American plant.  It’s made by concentrating the sweet compounds that are found in the plant. It’s been around for a long time and seems to be fairly safe by comparison.  For me, the key point here is a naturally occurring sweetener versus a synthetic substitute.  So I have chosen to replace sugar in my coffee and tea with stevia.

How about Sucralose?

Sucralose is also known as Splenda.  It’s a modified form a sucrose, which is sugar.  It’s made by taking out the hydrogen-oxygen groups from places on the sucrose molecule and adding chlorine in their place.  Sucralose also passes through the body without changing and it doesn’t break down for energy.  So it comes in, provides the sweet taste and leaves.  Additionally, it’s not transformed by heat, so it’s a good choice for baking.  Overall it’s probably not a terrible choice.


SodastreamBUT …I REALLY like Soda!?  What do I do?

Well, I like soda too, so I switched to Sodastream.  It’s a company that makes a carbonated water machine and flavors.  I find the flavors to be great and I really enjoy it.  Here’s how it works:

You fill up one of their bottles with water – just regular water.  Then hook it on to their machine, and carbonate the water.  It simply uses large, 60L Co2 canisters.  Then you add whatever flavoring you want, and off you go!

Additionally, I like the fact that Sodastream uses their own reusable bottles, so you aren’t generating more plastic bottles for the environment to absorb, and you aren’t dealing with BPA issues from the linings of aluminum cans.  That’s a win-win!



fruit dropsIs Sodastream a better health choice than Diet Coke?

Overall it IS a better health option than diet coke. Sodastream does a good job avoiding a lot of the bad products often found in soda.   Their sugar flavorings use …sugar.  Yup …regular sugar.  But a lower amount. Correspondingly, the calories are also lower.  Their diet flavorings use either sucralose or stevia.  No aspartame is used.  The sodium levels are about 2/3rds of normal diet soda.

Sodastream also had flavorings called Fruit Drops that are not sweetened and more like drinking carbonated lemon water, or orange, etc.   They are actually quite good if you don’t like a ton of sweetness.  They have no sweeteners, no caffeine, no preservatives, and no sodium.  It is, essentially, drinking water.


But what does all this cost?

I did a cost/benefit analysis to walk myself through the decision:

Note: This comparison will be done in metric.  All currency is in US Dollars.  There is a disparity between the serving size of Coke (355ml, or 12 ounces) and Sodastream which is 250ml.  Therefore we will do the cost comparison based on ml volume which is the lowest common denominator.

Each Sodastream CO2 Canister will make 60L of soda.  Each bottle of flavoring will make 9L of soda. For nutritional comparisons, each bottle of flavoring contains 36 servings at 250ML per serving – or 70% of a 355ML can of coke.


Diet Coke Costs:

1 can is 355 ml, a 12 pack is 4260ml.

A 12 pack of Diet Coke, retail price is $5.49.  That is $0.12/ml

A 12 pack of Diet Coke, sale priced is $3.34.  That is $0.08/ml


diet colaSodastream Costs:

Sodastream startup package:  Fizzi Machine, two 60 liter CO2 bottles, two 1 liter BPA-free plastic bottles costing $100.  If we want to paint an accurate picture of switching over to Sodastream, then we’ll need to amortize the startup costs into the ongoing expenses.  (By the way, if you don’t want to deal with amortization, then treat the original purchase as a sunk cost and be done with it.  But if you want to geek out completely, keep reading the next few paragraphs.)

Amortization:  Given that the manufacturer’s warranty is 2 years, we’ll use that time frame as a baseline.  If we assume people will drink the recommended 2 liters of water per day, then we can amortize the cost of the startup package by liter per unit of time.  2 liters, or 2000 ml, per day for 2 years is 1,460,000ml.  If we amortize the cost of the startup package over 2 years of usage, based on 2 liters per day that totals an added cost of $0.007 per ml.

Ongoing costs will be based around CO2 bottle costs and flavor bottle costs, now that we have established a static value for amortization of the original equipment purchase.

A 60000ml CO2 refill costs about $15.  Therefore, the cost of CO2 is simply $0.025/ml

Flavor bottles will make 9000ml of soda.  Their full-retail cost is $5.99 (rounded to $6) per bottle.

That comes to $0.07 per ml.

Total cost of Sodastream at full-retail:  $0.102/ml

Total cost of Sodastream at 20% sale: $0.08/ml


Bottom Line:

Sodastream is just marginally cheaper than buying Diet Coke at full retail.  However, in a sale situation, the edge goes to Coke, UNLESS you can find the Sodastream flavors on sale.  Often there are 20% off coupons available, and those drop the price to $0.08/ml which is exactly what Diet Coke is on-sale.  I don’t think that’s by happenstance.


My Take-Away

teaMy plan ended up being to transition off Diet Coke, to Sodastream, and then move to healthier options from there.  So far, that’s exactly what is happening.  I find myself drinking a variety of beverages now – including Sodastream diet caffeine-free drinks, Sodastream drops, water, Isagenix Hydrate, tea and coffee.  It has been at least 20 months since my last Diet Coke.  I don’t miss it at all and I feel better than I have in years.

It’s had the overall impact of reducing sugar and calories while upping my hydration and fluid intake. Unexpectedly, I lost all the water I was retaining and I can’t possibly explain how good that felt.  For many years after a previous knee injury, I had just come to believe that my right leg would always retain a bit more water than the left as a result of the injury.  But that’s not the case now.  I can’t positively tie it to diet coke …but that’s what it certainly appears to be.

This may sound really odd …but it’s like my body was waiting for me to meet it halfway in getting better.  All I had to do was make one simple change and it was ready to respond and reward me with better health.

3 Responses

  • Susen

    Thanks for your amazing research. Loved it! Appreciate both the science and your dedication to saying YES to your health. I’m finding I love decaf/herbal tea, and H2O with lemon or Emergen-C with electolyes+ Vitamin C once in a while. Developing a taste for RO H2O just as it is. The 64 oz. (Or 1/2 of one’s weight in ounces/day) is nourishing and I’m on track most days. Way to go, Ethan!

    • Thanks Susen! It’s amazing how you adapt and your taste buds change …at this point it’s been over a year since I have had a diet coke and I don’t miss it at all!

  • Susen Fagrelius

    Yay! It all goes back to whatever is the most health-full choice we can make for ourselves along that Unplowed Road😊S


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