Overview

For many years, scientists believed that postprandial (post-meal) glycemic impact (GI) of the foods you eat solely determined the glucose increases after meals. Your doctors and nutritionists rely on GI to determine how friendly each food is to your overall blood sugar. 

This idea was formed because humans share the same physiology, so naturally, our bodies should respond in the same way… But do they?

Controlling postprandial glucose spikes has been a goal of physicians for decades. This is because having continuously elevated glucose levels can lead to diabetes, and other related illnesses such as dementia.

Scientists constantly debate the best way to control blood sugar levels. However, new data regarding a personalized postprandial targeting diet may be the best way to keep control of your blood sugar levels. 

By gathering enough information about how your body responds to different foods, you can ultimately create a personalized diet that optimizes your blood sugar. Healthy blood sugar control is essential for optimal health, no matter what goals you have.

In this article, we will briefly explain the physiology of food absorption, as it is paramount to understanding how a personalized postprandial-targeting diet is so effective. Then we’ll switch gears to a deep dive into the science behind individualized blood sugar response to food, and the personalized postprandial-targeting diet.

What Happens When You Ingest Food With Respect to Blood Sugar?

When you ingest food, your gut digests the food into simple units that can be absorbed. The digestion of food starts in your mouth, where chewing and some salivary enzymes start breaking down your food. As it moves through the stomach and small intestine, your digestive enzymes break down carbohydrates, proteins, and fats into sugars, amino acids and peptides, and fatty acids and glycerol, respectively.

Different carbohydrates have different structures and additional food components, which can affect their glycemic index. Also, combining carbohydrates with fibers or proteins and fats will slow down carbohydrate absorption, thus reducing the glycemic impact of your meal. This is why the dietary recommendations for managing blood sugar tell people to never eat high-carb foods without adding protein or fibers.

After food moves through your small intestine, it enters the colon or the large intestine. Aside from absorbing water, minerals, and vitamin B12, it houses your gut microbes. These microbes aid in the breakdown of complex foods and produce certain nutrients (i.e. vitamin K). Some are also involved in regulating blood sugar levels as they act directly on the liver.

Your gut flora partly controls how your body responds to food, and your microbiome signature is unique to each individual person, just like your fingerprint is. A personalized postprandial-targeting diet is so effective because it is personalized for your microbiome. No two microbiomes are the same, and no two postprandial-targeting diets are the same.

Previously, nutritionists and researchers thought that blood sugar responses to each food were the same for everyone. So, they developed standardized ways to measure blood sugar responses to food called glycemic index and glycemic load, which you can read about in our Slow Carb Diet article.

How Does Personalized Postprandial-Targeting Diet Benefit You?

Recently, technologies such as continuous glucose monitoring (CGM) have made it possible for you to monitor your blood sugar from home, and it’s actually accessible to non-diabetics too. Clinical studies also show that they can help you identify which foods stabilize your blood sugar the most and which foods tend to throw off your blood sugar. 

In a recent study, researchers collected data from 327 American individuals without diabetes. The mean age of the participants was 43, and they were 78.0% female. Participants logged their food intake for 6 days. Then, they used a CGM to measure blood glucose levels every 5 minutes.

To prevent interference with participants’ regular diets, only 4 meals were standardized. 

The standardized meals revealed that glycemic responses varied greatly from one individual to another. The maximum blood sugar increases varied from 6 to 94 mg/dL among the participants.

To improve the accuracy of this approach, researchers refurbished a predictive model that took the following factors into consideration :

• The individual’s body mass index (BMI)
• Waist-to-hip ratio
• Cholesterol level
• Hemoglobin level
• Details about the composition of the microbiome (using feces)

Combined with CGM devices, this model was significantly more accurate in predicting postprandial glycemic response compared to using caloric and carbohydrate content alone.

In another study that included 800 participants without prediabetes or diabetes, researchers attached continuous glucose monitoring devices to participants and observed their glycemic responses to more than 46,000 meals.

Participants were also provided with a smartphone app to write down different activities during the day (e.g. exercise, sleep, etc.). Finally, researchers collected stool samples to analyze the composition of gut microbiomes.

Interestingly, certain foods spiked blood sugar in some individuals, but had minimal effects in others. For example, a specific set of participants had higher postprandial glycemia after eating sushi compared to when they consumed ice cream. Interestingly, the original glycemic impact model would predict higher blood sugar in response to ice cream than sushi.

Using all of this data, researchers were able to develop a machine-learning algorithm that takes into account the individual’s:

• Dietary habits
• Physical features (e.g. weight, height)
• Physical activity
• Hemoglobin and cholesterol levels
• As well as their gut microbiome

This new algorithm successfully predicted post-meal blood sugar in all 800 participants. It also worked perfectly for 100 other participants.

This new information makes it possible to confidently develop personalized postprandial-targeting diets for all types of individuals.

The Role Of The Gut Microbiome In Postprandial-Targeting Diet

Now that you know that the gut flora affects your blood sugar responses to food, let’s look at how the microbes do so through this clinical study.

So, let’s break down the design of the study:

Researchers conducted this clinical trial in the United States, where participants came from a multiethnic group. All participants had an HbA1c below 6.5. This was necessary to exclude anyone with diabetes. 

Participants ate either an omnivorous or vegetarian/gluten-free diet, and researchers measured their blood glucose every 15 minutes, using CGM devices. The study spanned more than 27,000 meals and their postprandial glycemic response. 

Approximately 18,000 of the meals were standardized and provided to the participants. These meals had a diverse range of macronutrients. They also did the analysis along with looking at the participants’ bacterial profile based on their ribosomal RNA. 

Analyzing the final results revealed that postprandial glycemic response is controlled by more than just the chemical composition of the food itself. Instead, individual characteristics, such as height, weight, and physical activity, play a crucial role.

More importantly, researchers highlighted the massive role of the gut microbiome composition in determining how your body responds to food intake.

Microbiome balance, along with genes related to carbohydrate and amino acid metabolism influenced glucose fluctuations after meals. The study concluded that having a suboptimal gut microbiome is correlated with suboptimal glycemic regulation.

Personalized Postprandial-Targeting Diet Versus The Mediterranean Diet

The Mediterranean diet is well-known for its balanced composition that promotes good health and stable blood glucose levels.

To analyze the practical uses of a personalized postprandial-targeting diet, researchers conducted a study placing this type of diet, versus the Mediterranean diet.  

For 6 months, 225 participants with prediabetes followed either a personalized postprandial-targeting diet or the Mediterranean diet. After 6 months, researchers compared the results of the two diets.

The study concluded that the personalized postprandial-targeting diet was significantly more effective at controlling post-meal blood sugar response and lowering the risk of prediabetes compared to the Mediterranean diet.

Six month HbA1c levels dropped by 0.08% in the participants following the Mediterranean diet, and by 0.18% in the personalized postprandial-targeting diet group.

Takeaway 

Personalized postprandial-targeting diets can revolutionize the world of healthy eating by using unique characteristics about each person to determine what they should be eating. This diet is not a “one size fits all” approach; it is a way of eating that’s unique from person to person.