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Tale of Two Blood Sugars: How Carbs Affect Us Differently

When it comes to carbohydrates, the specific foods that contain them are just as important as purely the amount you eat. If you want to normalize and stabilize your blood sugar levels and insulin secretion, it's important to avoid foods that spike these markers. Eating highly processed foods brings its own set of problems due to the mostly unhealthy ingredients and the high refinement of their natural components. And we all know what these «junk foods» are.

But what about carbohydrate-rich foods that we consume in their natural form - like fruit or whole grains? Do these have the same effects on blood sugar in everyone? Can you assume they are «good» for you if they are less problematic for other people?

A groundbreaking study by the Weizmann Institute of Science published in 2015 provided the first deep insight into this question and the impetus for further studies of a similar nature. In this study, the blood glucose levels of 800 people were monitored with continuous glucose monitors for one week. They recorded all the meals the participants ate and also had them eat identical high-carbohydrate meals.

The most important finding was that blood levels differed significantly between individuals.

Image from my book: FOOD FOR HEALTH, available on Amazon

It turned out that the composition of the microbiome - the accumulation of microbes in the colon - contributed most to these differences. It was also found that blood glucose could be stabilized by avoiding blood glucose-triggering foods, and consistent changes in the microbiome were observed.

Example 1: Pure glucose solution versus bread

One would assume that a pure glucose solution, like the one you sometimes have to drink at the doctor's office for a blood glucose test, would raise blood glucose levels higher than the same amount of glucose in the form of starch in a whole food. But that's not the case for everyone.

Here, two participants consumed the same amount of glucose solution, and both had blood sugar responses in a similar and healthy range. But when confronted with bread, as expected, one participant showed a lower blood glucose spike than with the glucose-only solution. Still, the other participant had a much higher blood glucose spike than with glucose-only!

Image from, D. Zeevi: Personalized Nutrition by Prediction of Glycemic Responses.

Example 2: Cookies versus banana

You can already guess what happened in this challenge - again, one of the participants responded to the cookies with a higher blood glucose level than to the banana, but for another participant, the response was just the opposite.

Image from, D. Zeevi: Personalized Nutrition by Prediction of Glycemic Responses.

What can we learn from this?

Because blood glucose responses vary so much from person to person, dietary optimization must be individualized for high-carbohydrate foods.

Image from my book: FOOD FOR HEALTH, available on Amazon

Don't just assume that whole wheat bread is necessarily better than white bread (yes, there's a study on that, too) or that fruit is okay because it's a «natural» product. Always pay attention to your reaction to certain foods. If you feel tired, hungrier, or even ravenous after a meal, chances are, you are not reacting well to it.


Find more nutrition facts and tips in my book FOOD FOR HEALTH, available now on my shop and on all Amazon Marketplaces!


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