Do Tomatoes Have Too Many Carbohydrates?

Eat greens for vitamin K

Looks reasonable to me

Dr. Richard Bernstein wrote a great book advocating strict carbohydrate restriction for folks with diabetes.  I’m talking about a max of 30 grams a day, compared to 250–300 g in the standard American diet.

Dr. Bernstein cautions his diabetic patients and readers of Diabetes Solution to keep a tight lid on consumption of tomatoes.  An excerpt from page 149:

If you have them uncooked in salad, limit yourself to one slice or a single cherry tomato per cup of salad.

His concern is that tomatoes will raise your blood sugar too high.

That doesn’t make sense to me.  A 3-inch diameter tomato has 7 grams of carbohydrate, 2 of which are fiber.  So the digestible carb count is only 5 grams.  That’s not much.  So do tomatoes have a high glycemic index?  Unlikely, although it’s hard to be sure.  Good luck finding a reliable GI for tomatoes on the Internet.

I think Dr. Bernstein’s wrong about this one, which is rare.  I suppose it’s possible that tomatoes deliver some other substance to the bloodstream that interferes with carbohydrate metabolism, but Dr. Bernstein doesn’t mention that.

Do tomatoes play havoc with your blood sugars?

Steve Parker, M.D.

5 responses to “Do Tomatoes Have Too Many Carbohydrates?

  1. I have to agree with you. I’ve never experienced that from even eaten an entire tomato 🙂

  2. Dr. Bernstein Diabetes Solution is about his success managing diabetes. You want his results, you can follow his prescription. We are blessed with inexpensive blood sugar meters and the freedom to self-experiment to find what works best for our health. Most people (me included) find it very difficult to be as disciplined as Dr. Bernstein. Eat a tomato and test. Even if he is wrong I don’t think it is something to worry about.

  3. If you really love your tomatoes and are worried about blood sugar, you can always ferment them.
    That is the old school way to make salsa, ketchup etc.
    Easy to do, and tastes great.
    One example here, but google it and you’ll find many.

    That said, you would have to eat a lot of (overripe) tomatoes to get a lot of sugar. But those same overripe tomatoes are perfect for salsa and ketchup making.

  4. “Do tomatoes play havoc with your blood sugars?”
    Not mine!!
    Tomato GI of 15 here

  5. Sadly tomatoes do cause a huge blood sugar spike for me. If you are diabetic (or prediabetic) the best thing you can do for yourself is test & track as Dr. Bernstein describes in his book. Each person is different. Once you understand that cellular damage starts at BS levels of 140 it is much easier to practice the level of discipline needed.