Your blood sugar on high carb versus low carb


How does a carb-rich vs. low-carb diet affect your blood sugar? Dr. Unwin did a simple experiment to investigate this, where he measured how his blood glucose responds to the two different diets.

The picture above shows his blood sugar after a high-carb breakfast. 10.2 mmol/L (184 mg/dl) is almost diabetic high, and even double compared to his pre-meal value. Not so good, given that this is the recommended diet for diabetics.

So what happened after a low-carb meal instead?


5.9 mmol/L (106 mg/dl). Nice and stable!

If you want improved blood-sugar readings, check out the links below.


Low carb for beginners

How to reverse type 2 diabetes


Why your fasting blood sugar might still be high on low carb

Would you get a tattoo showing your level of blood sugar?

Type 2 diabetes


  1. Linda
    I’m not diabetic,but have low blood sugar every morning..I’ve been following a LCHF way of eating for only a couple of weeks now and I am feeling better except for when I get up every morning. My doctor says to get up and eat peanut butter crackers in the middle of the night but I don’t want to do that,carbs,any suggestions?
  2. EvgeniaBB
    Eat some cheese or sausage if you wake up at night because you are hungry.
    Waking uo intentionally to eat some high carb food is a bad idea, you won't feel any better.

    In my family everyone loves eating at night. If I don't have dinner very late, I can never fall asleep without a snack before going to bed, or during the night if I wake up. I think it's genetic in my family. By the way, we are all very slim no matter what we eat. And when I tried having butter coffee in the morning instead of meal, I gave it up after nearly fainting before lunch. I think it's all because of my low glucose. But low carb snacks work perfectly well for me if they have some protein.

  3. Michael Hennessey
    This is awfully misleading. I'm T2D and eat a plant based diet that includes a lot of carbs and my numbers don't go that high. This person in the article is also probably consuming a lot of fat which will cause his glucose to spike. Eliminating fat from animal food and eliminating processed foods is the key to controlling and even eliminating T2D. Check out for unbiased reviews of studies and the effects of food on T2D.
    Reply: #5
  4. 1 comment removed
  5. Andre
    Hi Michael,

    If you are satisfied with your diet. This is great and be happy.
    I myself was T2 diabetes taking 2 x 500 mg of Metformin per day. I was trying to follow as much as possible the standard nutrition guidelines and eating a lot of vegetable and grains. Despite this, I still had an A1C test in excess of 6.2 %.
    I started the LCHF diet (ketogenic) just a year go and was able to completely reverse my T2 diabetes (no more medication required). As a premium, I also lost 95 pounds and was able to eliminate the need of High blood pressure medication.

    This diet is not misleading as it is certainly for a lot of people like me to reverse their T2 diabetes and lose weight.

    Can you claim the same with your plant/high carb based diet?

  6. Marilyn Herewane
    Im with you andre ...that diet at the top will have your numbers double in no time because thats hospital breakfast and my a1c went from 6.3 to 7.5 after a surgery and hospital stay and to say fats spike blood sugar is rediculous because fat has less affect than carbs and protein and ive been diabetic for 30 yrs so ive tried a lot of diets and none have ever worked better than lchf to control it
  7. Cara Lewis
    Linda if you are eating correctly on a lchf diet that should not happen, but try eating some cheddar before bed. Lchf i would say about 1oz
  8. Helen Anderson
    I think this experiment has a serious design flaw. The problem is that you have been low carbing for months or years, and that has altered your glucose metabolism, producing an artificially high reading when you suddenly consume carbs. I experienced the same phenomenon after a year or two of low carbing, and was afraid I'd become diabetic. Your pancreas is no longer responding to carbs as sensitively as when you were eating carbs on a daily basis. If you were to take a 2 or 3 week "break" from low carbing or keto, you would get altogether different results in your experiment. This is not to say that there is anything wrong with low carbing -- just that it changes your body's response to carbs, at least temporarily, so your results are probably quite skewed.

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