Caffeine . . . Weight Loss Wonder Boy or Sneaky Scoundrel?

I’ve been looking for the answer for quite some time. . . what role does caffeine play in your and my weight management journey?  The answer gave me a headache. . . literally and figuratively.

As many of you, including my office staff, know, I love my Diet Dr. Pepper (and my bacon).  I found that being able to sip on a little soda throughout the day significantly helped the carbohydrate cravings and munchies during a busy and stressful day at the office.   Diet Dr. Pepper contains caffeine, however, I wasn’t really worried.  Caffeine has been well know to have a thermogenic effect which increases your metabolism and has been thought for many years to help with weight loss among the weight loss community.

Diet Dr. Pepper is, also, one of only four diet sodas on the grocery store shelves that doesn’t contain acesulfame potassium (click here to see why most artificial sweeteners cause weight gain).  The four diet sodas that I have been comfortable with my patients using are Diet Dr. Pepper, Diet Coke, Diet Mug Root-beer and Diet A&W Cream Soda.  These are the last four hold out diet sodas that still use NutraSweet (aspartame) as the sweetener.  Most of the soda companies have switched the sweetener in their diet sodas to the insulinogenic acesulfame potassium because it tastes more natural and aspartame has been given a media black eye of late.  However, NutraSweet (aspartame) is the only sweetener that doesn’t spike your insulin or raise blood sugar (click here to find out why that is important).

Yes, I know.  The ingestion of 600 times the approved amount of aspartame causes blindness in lab rats (but we’re not lab rats, and . . . have you ever met someone that drinks 600 Diet Dr. Peppers in a day?  The lethal dose of bananas, which are high in potassium that will stop your heart, is 400).  Aspartame can also exacerbate headaches in some (about 5% of people) and I’ve had a few patients with amplified fibromyalgia symptoms when they use aspartame.   But for most of us, its a useful sweetener that doesn’t spike your insulin response, halting or causing weight gain.

But, over the last few years, I’ve noticed that increased amounts of Diet Dr. Pepper & Diet Coke seem to cause plateauing of weight and decreasing the ability to shift into ketosis, especially mine.  I’ve also noticed (in my personal n=1 experimentation) that my ability to fast after using caffeine regularly seems to be less tolerable, causing headaches and fatigue 8-10 hours into the fast, symptoms that don’t seem to let up until eating. Through the process of elimination, caffeine seems to be the culprit.

Red Bull in caffeineAfter mulling through the last 10 years of caffeine research, most of which were small studies, had mixed results, used coffee as the caffeine delivery system (coffee has over 50 trace minerals that has the potential to skew the results based on the brand) and never seemed to ask the right questions, the ink from a study in the August 2004 Diabetes Care Journal screamed for my attention.

It appears that caffeine actually stimulates a glucose and insulin response through a secondary mechanism.   The insulin surge and glucose response is dramatically amplified in patients who are insulin resistant.  Caffeine doesn’t effect glucose or insulin if taken while fasting; however, when taken with a meal, glucose responses are 21% higher than normal, and insulin responses are 48% higher in the insulin resistant patient. Caffeine seems to only effect the postprandial (2 hours after a meal) glucose and insulin levels.  The literature shows mixed responses in patients when caffeine is in coffee or tea, probably due to the effect of other organic compounds (1).

Caffeine Effect on glucose insulin

Caffeine effect on plasma glucose and plasma insulin compared to placebo (1).

Caffeine also diminishes insulin sensitivity and impairs glucose tolerance in normal and already insulin resistant and/or obese patients.  This is seen most prominently in patients with diabetes mellitus type II (stage IV insulin resistance).  Caffeine causes alterations in glucose homeostasis by decreasing glucose uptake into skeletal muscle, thereby causing elevations in blood glucose concentration and causing an insulin release (2-6).

Studies show that caffeine causes a five fold increase in epinephrine and a smaller, but significant, norepinephrine release.  The diminished insulin sensitivity and exaggerated insulin response appears to be mediated by a catacholamine (epinephrine, norepinephrine & dopamine)  induced stress response (5).  Caffeine has a half life of about 6 hours, that means the caffeine in your system could cause a catacholamine response for up to 72 hours depending upon the amount of caffeine you ingest (7).

The reason for my, and other patient’s, headaches and fatigue after a short fast was due to the exaggerated stress hormone response.  Increased levels of insulin were induced by a catacholamine cascade after caffeine ingestion with a meal, dramatically more amplified in a person like me with insulin resistance. The caffeine with the last meal cause hypoglycemia 5-7 hours into the fasting, leading to headaches and fatigue that are only alleviated by eating.

Even when not fasting, the caffeine induced catacholamine cascade causes up to 48% more insulin release with a meal, halting weight loss and in some cases, causing weight gain.

Caffeine is not the “Wonder-Boy” we thought it was.

How much caffeine will cause these symptoms? 50 mg or more per day can have these effects.


Ingestion of caffeine has the following effects:

  • 20-40 mg – increased mental clarity for 2-6 hours
  • 50-100 mg – decreased mental clarity, confusion, catacholamine response
  • 250-700 mg – anxiety, nervousness, hypertension & insomnia
  • 500 mg – relaxation of internal anal sphincter tone (yes . . . you begin to soil yourself)
  • 1000 mg – tachycardia, heart palpitations, insomnia, tinnitus, cognitive difficulty.
  • 10,000 mg (10 grams) – lethal dose (Yes, 25 cups of Starbucks Coffee can kill you)

The equivalent of 100 mg of in a human was given to a spider, you can see the very interesting effect on productivity.  How often does the productivity of the day feel like the image below?

Spider Normal

Normal Spider (9)

Spider Caffeine

Spider on caffeine (9)

Beware that caffeine is now being added to a number of skin care products including wrinkle creams and makeup.  Yes, caffeine is absorbed through the skin, so check the ingredients on your skin care products.

Diet Dr. Pepper, my caffeine delivery system of choice, has slightly less caffeine (39 mg per 12 oz can or 3.25 mg per oz) than regular Dr. Pepper.  I found myself drinking 2-3 liters of Diet Dr. Pepper per day (long 16-18 hour work days in the office).  After doing my research, I realized that my caffeine tolerance had built up to quite a significant level (230-350 grams per day).

So, a few weeks ago, I quit . . . cold turkey.

Did I mention the 15 withdrawal symptoms of caffeine? (8)

  • Headache – behind the eyes to the back of the head
  • Sleepiness – can’t keep your eyes open kind of sleepiness
  • Irritability – everyone around you thinks you’ve become a bear
  • Lethargy – feels like your wearing a 70 lb lead vest
  • Constipation – do I really need to explain this one?
  • Depression – you may actually feel like giving up on life
  • Muscle Pain, Stiffness, Cramping – feel like you were run over by a train
  • Lack of Concentration – don’t plan on studying, doing your taxes or performing brain surgery during this period
  • Flu Like Illness – sinus pressure and stuffiness that just won’t clear
  • Insomnia – you feel sleepy, but you can’t sleep
  • Nausea & Vomiting – You may loose your appetite
  • Anxiety – amplified panic attacks or feeling like the sky is falling
  • Brain Fog – can’t hold coherent thoughts or difficulty with common tasks
  • Dizziness – your sense of equilibrium may be off
  • Low Blood Pressure & Heart Palpitations – low pressure and abnormal heart rhythm

I experienced 13 of the 15 that lasted for 4 days.   I do not recommend quitting cold turkey unless you have a week off and someone to hold your hand, cook your meals and dose your Tylenol or Motrin.  My wife thought I was dying. . . I thought I was dying on day two.  I actually had a nightmare about buying and getting into my own coffin.  It can take up to three weeks to completely recover from caffeine withdrawal.

The other way to quit is to decrease your caffeine intake by 50 mg every two days.   That means decrease caffeine by:

  • 1 can of soda every two days
  • 1/4 cup of coffee every day
  • 1/2 can of Energy Drinks every two days
  • 1 cup of tea every two days

The benefit of this method is that withdrawal symptoms are much less severe without the caffeine headache and the ability to remain productive.  It will take longer, but quitting cold turkey is not a pretty picture.  Been there . . . done that, . . . and I’m not going back. I actually lost another half inch off my waistline by day 5 of caffeine discontinuation.

What is the take home message here?  If you have any degree of insulin resistance, caffeine makes it worse and will amplify your weight gain as well as decrease the productivity of your day.


  1. Lane JD, Barkauskas CE Surwit RS, Feinglos MN, Caffeine Impairs Glucose Metabolism in Type II Diabetes, Diabetes Care August 2004 vol. 27 no. 8 2047-2048; doi:10.2337/diacare.27.8.204
  2. Jankelson OM, Beaser SB, Howard FM, Mayer J: Effect of coffee on glucose tolerance and circulating insulin in men with maturity-onset diabetes. Lancet 1527–529, 1967
  3. Graham TE, Sathasivam P, Rowland M, Marko N, Greer F, Battram D: Caffeine ingestion elevates plasma insulin response in humans during an oral glucose tolerance test. Can J Physiol Pharmacol 79:559–565, 2001
  4. Greer F, Hudson R, Ross R, Graham T: Caffeine ingestion decreases glucose disposal during a hyperinsulinemic-euglycemic clamp in sedentary humans.Diabetes 50:2349–2354, 2001
  5. Keijzers GB, De Galan BE, Tack CJ, Smits P: Caffeine can decrease insulin sensitivity in humans. Diabetes Care 25:364–369, 2002
  6. Petrie HJ, et al. Caffeine ingestion increases the insulin response to an oral-glucose-tolerance test in obese men before and after weight loss. American Society for Clinical Nutrition. 80:22-28, 2004
  7. Evans SM, Griffiths RR, Caffeine Withdrawal: A Parametric Analysis of Caffeine Dosing Conditions, JPET April 1, 1999 vol. 289no. 1 285-294
  8. Noever R, Cronise J, Relwani RA. Using spider-web patterns to determine toxicity. NASA Tech Briefs April 29,1995. 19(4):82. Published in New Scientist magazine, 29 April 1995

22 Comments on “Caffeine . . . Weight Loss Wonder Boy or Sneaky Scoundrel?

  1. Hi I signed up for your 10$ a month weight loss subscription. Is there a way to access it or is it something that comes out monthly? Thanks

  2. This post will kill my husband. One of the reasons he agreed to the Keto lifestyle and to become your patient was because you were addicted to Diet Dr. Pepper and somehow that made you someone he could trust. Weird, right? He will freak out if he finds out that on top of giving up his bread and rice, he may now have to give up his soda. Anyway, good for you and glad to see you made it out alive. Husband has appointment with you this week. He will be the guy with the bottle of Diet Dr. Pepper in his hand.

    • Holly,
      Take it one step at a time. That’s what I had to do. You can still lose weight with the caffeine. It’s when you get to the plateau just before your goals that you may need to consider weaning or removing it from the diet. I understand that the Diet Dr. Pepper is often the tool that allows you to get past the carbohydrate addictions. Once you’ve conquered that beast, then you can look at conquering the caffeine monster. Take it one step at at time . . . baby steps, for some of us.

  3. Pingback: Why I Quit Coffee | Linda Gardner's Blog

  4. 😦 very sad post. I like coffee. I am the type of person who can drink a cup of coffee and still go to sleep. I dont drink it to say awake or increase alertness. I just like the take of it. Sniff, sniff

  5. Doc, just wondering, I am drinking decaf coffee now (with coconut cream, not milk!). Does this get me off the hook? I am T2D, and I am hoping that morning decaf will result in lower BG readings in the mornings upon waking. Any thoughts or medical wisdom? I empathize with your caffeine withdrawals, I had a week of headaches and took a few days away from resistance training 😦

    • Not all decaf coffees are created equal and there still may be some caffeine in them. You’ll have to monitor your ketones to determine if it is keeping you out of ketosis.
      Adam Nally, D.O.

  6. Thank you for this excellent post, Dr. Nally. I’ve been an advent coffee drinker for years. I liked it hot and very strong and would consume between 6-8 8oz cups per day. The heart-racing at night was a biggie for me, but I am also a Type 2 Diabetic and would always notice high morning readings. I began reducing my coffee intake over a period of months until I was only consuming 1-2 8oz cups per day… same issue, heart-racing and high morning readings. A month ago, I switched to green tea in the morning and herbal teas the rest of the day. No heart-racing at night and my morning readings have come down about 10-20 pts. I’ve not noticed any weight loss as a result, but the other issues are gone. I think the caffeine in green tea is somehow different than that in coffee? or perhaps buffered by something else in the green tea? I’m not sure, but I do not get the same spike in my glucose or insulin levels from it.

    • Lori,
      The green tea has a compound that converts to a “caffeine-like” product. The tea’s have variable amounts 20-200mg depending on the tea and the concentration. I have not found the eCGC (green tea extract) to cause the same problem at this point, but the tea itself seems to be much stronger. Black tea and oolong tea seems to be similar to green tea.

  7. I was happy to find this caffeine information. I am personally very, very sensitive to it, so knowledge is powerful for me.

    You may appreciate knowing that Shasta has a NEW Sparkling Water line, which is being marketed as a genuine soft drink alternative. The flavors include a cola and a root beer. I was fortunate and was able to taste the root beer, and it really was very good. And the great thing is that they are simply sparkling water with natural flavor essence. They are brand new though, so it may take a while for them to show up in the stores.

    Here’s more information on all of the soda/pop alternatives I discovered…

  8. Doc Nally how long after drinking a cup of coffee or Diet Coke should u check with the keotonix. I have limited my caffeine but do miss coffee a lot sndwNt to know if it effects me.
    Thanks jodi

    • Caffeine has the half life of 7 hours which means that excessive caffeine use can adversely affect your cortisol, and thereby your insulin for up to 72 hours after ingesting it.

  9. Doc Nally. I just re-read the information. I have already stopped caffeine which wasn’t easy. I just miss coffee.. I am drinking AW mug root beer which has no caffeine. Maybe I should not rock the boat but jimmy and you always say we are individuals and what you can handle is individualized. So can you drink dec coffee once a day without kicking out of ketosis? Or is all the other side effects no worth it. Your thoughts please…
    Thanks jodi

  10. How about caffeine- free Diet Dr Pepper? Is that OK? The bubbles are what I like. I drink the regular until 1:00 and then switch to caffeine- free. I could easily change over to all caffeine- free Diet Dr Pepper.

  11. Doctor Adam,
    I avidly appreciate all you have made available to us. Using Keto//OS. Feeling great and Very excited about Keto.

    Just thought I’d let you know … I believe the spider pics are not accurate and were produced only to make a point.

    PS the new flavored waters say natural flavors on the label. Scary ingredients!

Leave a Reply

Fill in your details below or click an icon to log in: Logo

You are commenting using your account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s

%d bloggers like this: