How I Discovered I Was Carbohydrate Intolerant

Carbohydrate Intolerance

As a functional medicine physician, I’m used to helping my patients find the solutions to their health problems.  When they start gaining weight and feeling fatigued, for example, I become a kind of detective, searching for clues as to how their diet and lifestyle might be interfering with their bodies need to achieve optimal function.  

So, when I myself began putting on some extra pounds and struggling with late-afternoon exhaustion, I had to look at my own food choices.  A review of my own labs revealed that my blood sugar levels were in the pre-diabetic range.

This made no sense to me.  The usual reason for high blood sugar is a diet high in refined sugar, white flour, and other refined grains, such as white rice.  But I had long known how unhealthy such foods are, and I rarely ate them.  What was going on?

When I finally discovered the answer, I must admit, I was shocked.  The problem, I realized, was the so-called “healthy carbs”—whole grains like brown rice, quinoa, and oatmeal, as well as starchy foods like sweet potatoes and beans, and high-glycemic fruits like watermelon, mango, and pineapple.  And indeed, these foods are healthy for many people.  But, not for me.  My system just couldn’t handle all the sugar.

As soon as I cut back on these sweet and starchy “health” foods, my own health improved dramatically. I quickly lost the extra weight I had gained and my usual blazing energy was soon restored.  A little more research soon revealed that my problem had a name: carbohydrate intolerance.

In fact, carbohydrate intolerance is such a common problem that I devoted an entire chapter to it in my recently released book, 10 Reasons You Feel Old and Get Fat.  In the book, I explain that no matter what your age, you don’t have to feel old.  Nor do you have to gain weight. You need only eat the foods and practice the lifestyle that enables your body to achieve optimal function.  That way, you can be lean, energized, and symptom-free at any age.  And you can avoid the frustrating symptoms, loss of energy, and excess weight produced by carbohydrate intolerance.

Do You Suffer from Carbohydrate Intolerance?

Take the following quiz and find out:

  1. Are you overweight?
  2. Do you feel fatigued much of the time, especially after eating a carb-heavy meal?
  3. Do you lead a largely sedentary life?
  4. Do you have the sense that your appetite is out of control?
  5. Do you frequently crave sweet or starchy foods such as bread, pasta, potatoes, or beans?
  6. Do you feel light-headed and dizzy when you get hungry?
  7. Is your blood sugar in the upper ranges of “normal” or beyond?
  8. Are you struggling with one or more symptoms, such a brain fog, anxiety, depression, skin problems, joint paint, aching muscles, hormonal issues, or sleep problems?

If you answered “yes” to one or more questions, try fourteen days of cutting out of your diet all grains, legumes (beans and peas), starchy vegetables (squash, sweet potatoes, yams), and fruit.  If you then experience a marked change in your symptoms, you might very well have discovered your own carbohydrate intolerance.  

Not everyone needs to be concerned with carbohydrate intolerance.  My wife, Janice, for example, is happily able to digest and metabolism complex carbs. Her diet is rich in whole grains, black beans, garbanzos, and fresh fruit—and if you are free of carbohydrate intolerance, you can enjoy the same foods.  If, however, you’re like me, you want to be careful and consume no more than two or three portions of complex carbs and two or three low-glycemic fruits (fresh berries, citrus fruits, apples) each week.

To learn more about carbohydrate intolerance, order my new book, 10 Reasons You Feel Old and Get Fat.  

  • Sofía V

    Hi Dr. Frank!

    Sofía, from Mexico City if you remember me! Thank you for sharing this piece : ) I can relate to a few observations named above but have been skeptic if it were my nerves since you know, GF whole grains “are so good for you”. No question our bodies are all different and will naturally respond different too. Have a nice week!

  • laurakraber

    Thanks, Sofia! I will make sure that Dr. Frank gets your message.

  • Merrill Macfarlane

    Hi There,
    I am on day 5 of the 2 week revitalize and have lost 4 pounds so far. I have another 3 pounds to go and am stunned at how much better my sleep is. I have known since I was in my mid 50’s that carbs were not my friend but always convinced myself that 1 or 2 glasses of wine with dinner weren’t a problem. I work out 3 times a week and really ‘bonked’ today without the carbs. Is there anything I can add to the plan to help me out here? I really want to continue with my strength training. I am not able to get your vitamins in Canada so have tried to match as well as I can.
    Love the recipes, so easy to follow.

  • Katie Carter

    Thanks for sharing your personal discovery of being carbohydrate intolerant. I too am in my 60’s and have learned that what I could get away with eating in my 40’s and 50’s has now changed as I grow “wiser”. As a female nutrition consultant I thought I knew what the healthy carbs were – but the more I experiment the more I learn what my body and hormones can handle. I love your new book, 10 Reasons You Feel Old and Fat and have highlighted many statements to share with my clients and students.
    For me the key is just like you said in the book.. my PERSONAL tolerance to so called healthy carbs depends on my sleep, exercise, meditation or downtime and how I handle the stress of each day, or even each hour. Thanks for all your hard work and wise wise wisdom!
    BTW – I love the example how you and your wife have different tolerances to these carbs – made so much sense!

  • laurakraber

    Thanks for your kind words and best of luck with your health!
    – Be Well Coach Laura

  • Kathy R Mimi

    Almost 3 years ago, due to my husband;s diabetes, we stopped eating carbs for about 6 weeks. I was always a potato, pasta, rice person. I lost 20 pounds during that time, taking me to 128lbs. My husband lost 0. When I told my husband I was having dreams about al
    most drowning myself in a bowl of mashed potatoes, he said, so, if you want a potato, eat it. What happened was, after not eating carbs, now I can’t tolerate them. They hit my system so fast, that at times, before our meal is down, I feel bloated, and, sometimes unable to form a cohesive sentence. That being said, I have now lost another 8 pounds. I am soon to be 63, 5’3″ and weigh 20-1/2 pounds. How can I put some weight on?

  • Scorp19

    Hi. I’m carbohydrate intolerant, but also an ethical vegan. Prior to going vegan, I was a vegetarian but was on a long-term low carb diet and managed my weight fairly successfully for 10+ years. Since going vegan 4 years ago, I’ve really been struggling with weight gain, fatigue, brain fog, etc. However, eating animal products is not an option, as it is in complete violation of my ethics. Do you have any suggestions for a long-term low carb plant-based diet? As a vegan, it’s very difficult to avoid the types of foods you’re talking about here (e.g. beans, fruit, starchy vegetables, etc.)

  • Correctrix

    I’m vegetarian, and a lapsed vegan, and I feel your pain. I have quite simply resigned myself to eating eggs and dairy, because I can barely function if I don’t. I do try to eat as much fat and protein from non-animal sources as possible though. Eat Quorn, nuts, avocados, coconut, spirulina, mushrooms, and supplement with caprylic acid. Use psyllium husks for fibre. Use algal oil for omega-3 fatty acids. Don’t drink fruit juice or sodas: have water with a dash of lemon or vinegar.

  • ginabaccaro

    Am or am I not carb intolerant? I had symptoms of feeling tired in the afternoons, poor sleep patterns, weight gain around the waist and brain fog. My last fasting sugar was 100—pretty high. I’ve been on nothing but lean proteins, leafy greens and a scant amount of nuts for the last 9 days and I’m miserable. I do daily walks and weight train 3 times a week. While my afternoon and early evening fatigue have improved, I am waking several times a night having hot flashes and feeling achy, unable to fall back to sleep. The aches continue until 9am. I’ve lost little more than 1/2 pound and no inches off my waist since I started. Oh. Did I mention I am hypothyroid and on armour and also post menopause. I am about to give up. I am totally miserable on or off carbs and sugar.

  • William

    If your diet has truly been that strict it may be worth looking into the “keto flu”. From what you have said it sounds like that. But I have no medical knowledge outside of my own research. A good place to learn about it is

  • Lizna

    It took me two month to detect that I am intolerant to carbohydrates. Pls be patient. I can take goods carbs like fruits but rice, any flour makes my heart beat fast, sleepy, dizzy and legless

  • ginabaccaro

    Hi. I’m back and yes…I believe I did have “keto flu” as you mentioned. After a day of some gentle carbs (bowl of oatmeal and chia seeds with a teaspoon of honey) and lots of water to flush everything out, I felt great again. I have lost so far, 5lbs and an inch from my waist. Giving myself a carb holiday seems to be working for me. Every 3 days I’ve been doing this. Not over doing it of course. Just allowing a “gentle starch” to the mix such as butternut squash. It’s working! YAY! Thank you for your reply!