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Can Diet Coke Raise Blood Sugar Levels?


I am a Type I diabetic and have done very well keeping my blood sugar under control.  About two weeks ago, however, my blood sugar started going over 200 for no reason.  Since I have not changed my diet or schedule, I have begun to question my consumption of Diet Coke.  

I have been drinking Diet Coke since I was diagnosed with Type I several years ago and it has not appeared to raise my blood sugar, but it is now the only explanation I can find.  I am going to try to stop drinking it to see what happens in the meantime, but this will be extremely hard since I usually drink about 16 ounces a day.

I just would like to know if Diet Coke (or any other diet soda) has raised anyone else's blood sugar levels.  Diet Coke is always listed as a "free food," so the possibility of Diet Coke raising my blood sugar saddens me greatly.  ***Is it true that the aspartame contained in Diet Coke might actually raise blood sugar levels (I think I read this a long time ago in an informational brochure but did not think twice about it since my blood sugar levels were great at the time)?***

Any information would be sincerely appreciated.
10 Responses
Avatar universal
Hi nnvp, thanks for coming to the Forum in search of answers.  Those of us who volunteer here are not medical professionals, but rather people who are affected by type 1 in one way or another.  I happen to be the mom of a now 18 year old son who was diagnosed 7-1/2 yrs ago.  My son is one of those folks that LRS talked about, whose bgl's are also affected by caffeine.  He did just as you suggested, experimented with removing the caffeine and he realized that it must have been causing him to be resistant to the insulin, much more so in the morning that any other time.  He does still drink diet sodas, though not as much as before and he tries to stay away from them before lunchtime and that seems to have helped with his control.

hope this helps and let us know how your own experiment turns out!
Avatar universal
For some DMers like us, caffeine or other stimulants can result in higher blood sugar.  Your experiment to cut down/out on Diet Coke might help you see if that's the culprit.

Sometimes, in our early stages with Type 1, we have what's called a honeymoon, during which time (which can last for about a year) our bodies are still able to produce some insulin.  Once the honeymoon is over and we've lost that ability completely, it is normal and natural that our need for insulin will increase.  It's not a steady increase, but we'll experience another -- but higher -- need for basal (long-acting) and/or bolus (short-acting, to cover food) insuiln.

If your higher numbers are in the morning (for example, if your preferred source of morning caffeine is a diet cola and not coffee or tea), then you might now have another common experience called Dawn Phenomemon where we are more resistant in the morning.  I think this is related to the surge of "get up & go" hormones that our bodies release in the morning.

Finally, if you're drinking diet soda from a soda fountain, it is also all too common that the soda labelled "Diet XYZ" might not really be pouring that beverage.  Lines get crossed, mixed, etc.  If you're drinking from cans or bottles, then you're getting the real thing.  ;-)

I'm not a physician, but have shared my personal experiences.  If you can't seem to explain and/or knock down your highs predictably, it's time to share the info, patterns, and test results with your endocrinologist and/or a certified diabetes educator.  They'll work with you and your particulars to ID the source of the highs and to figure out effective ways to treat 'em.

Good luck.  I'd love to hear back from you when you've figured it out.
Avatar universal
I think this is a VERY serious, unrecognized issue that people are continuously ignoring. My grandmother is a brittle diabetic and frequently drinks lots of Diet Coke. More recently she has been experiencing extreme chills on a daily basis - for which all medical professionals that she has visited can come up with no diagnosis.  Due to this, and in conjunction with "rumors" of the deadly sugar-substitute aspertame, I have recently been researching the effects of aspartame - via diet sodas -  on the body. My findings have been appalling, to say the least. Aside from those who suffer from diabetes, aspartame (included in diet sodas and many other foods and products. ex. Winterfresh gum, light yogurt & Flintstones Vitamins) is an extremely harmful - and deadly - additive.  
The effects of aspartame include and are not limited to:
   (list from www.dorway.com)
Abdominal Pain
Anxiety attacks
Asthmatic Reactions
Bloating, Edema (Fluid Retention)
Blood Sugar Control Problems (Hypoglycemia or Hyperglycemia)
Brain Cancer (Pre-approval studies in animals)
Breathing difficulties
burning eyes or throat
Burning Urination
Chest Pains
chronic cough
Chronic Fatigue
Excessive Thirst or Hunger
flushing of face
Hair Loss (Baldness) or Thinning of Hair
Headaches/Migraines dizziness
Hearing Loss
Heart palpitations
Hives (Urticaria)
Hypertension (High Blood Pressure)
Impotency and Sexual Problems
inability to concentrate
Infection Susceptibility
Joint Pains
Marked Personality Changes
Memory loss
Menstrual Problems or Changes
Migraines and Severe Headaches (Trigger or Cause From Chronic Intake)
Muscle spasms
Nausea or Vomiting
Numbness or Tingling of Extremities
Other Allergic-Like Reactions
Panic Attacks
poor memory
Rapid Heart Beat
Seizures and Convulsions
Slurring of Speech
Swallowing Pain
Vision Loss
Weight gain

Aspartame Disease Mimics Symptoms or Worsens the Following Diseases

Multiple Sclerosis (MS)
Parkinson's Disease
Multiple Chemical Sensitivities (MCS)
Diabetes and Diabetic Complications
Alzheimer's Disease
Birth Defects
Chronic Fatigue Syndrome
Lyme Disease
Attention Deficit Disorder (ADD)
Panic Disorder
Depression and other Psychological Disorders

That is just to list some of the known reactions to this poison, however comas and death have also been documented.  The main reason for these reactions is that aspartame (aspartylphenylalanine-methyl-ester) breaks down into poison (aspartic acid 40%, phenylanine 50%, and methanol 10%) when exposed to temperatures of 86+ degrees. ***Remember: normal body temperature is 98.6 degrees, which includes the temperature of your stomach where the soda sits!***  Ultimately the underlying condition which people become inflicted with is methanol poisoning.  All that being said, I would encourage you to explore the over-whelming amount of evidence and personal stories that are out there for yourself, as I have.  One night of research on this subject has turned me into an anti-aspartame-activist, so to speak. There are many sites out there which address the issues I mentioned, as well as other pertinent issues, in depth, and give explainations as to how continued distribution has been allowed. A very good page that I have found which briefly explains and concludes these problems, and those facing diabetics in particular, in a clear manner is found at (copy & paste into your browser address bar):


and another very informative site whose webmaster has lost several family members to methanol poisoning:


So, again, I very strongly urge you to research this issue yourself, alert others of this growing problem, and avoid all products that include aspartame in them.  If nothing else, drinking some water with a lemon (or other citrus/fruit slice in it for flavor) has countless mental and physical benefits over consuming a diet - or even non-diet - soda anyday.  Thank you for reading this post (despite its length and I hope it can help you or someone you know in some way. Good luck!

Avatar universal
I have been using Stevia for years now, and have had no problems with it at all. Stevia is derived from a natural plant that grows in South America. I am not sure, but i have heard that the Japanese use Stevia in their diet soft drinks and will not allow the use of Aspartame. Check this out it will be work your time.
Avatar universal
i am 14 and on an insulin pump. i have been diabetic for 9 years now.
i also experience that my blood glucose levels tend to fluctaute and have never find out why. I am now aware that this is due to the diet coke and other soda's that i drink and i am now trying 2cut down on drinking them as i would like better control over my sugar level.

I would like to thank you as my higher sugars has caused concern for me and my doctors, but now i know why i may be able to stop them.

Avatar universal
I've been drinking diet coke for as long as I remember, and believe, I just had my blood test, and everything is normal, including my sugar which is so low!!!!!!!!!.  Diet coke is good for me, some people brag that it has more sugar than regular coke, for me it's not true.  I'm living proof, that diet coke is good for me.  I drink about 5 cans a day, and I really enjoy it!

Tom M.
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