Your gut health plays an extensive role in your metabolism and blood sugar levels.

Here’s all you need to know about how your gut health influences your metabolism and blood sugar levels.

In this article we will discuss:

  • Metabolism & Blood Sugar 101: The Basics
  • The #1 Way to Boost Metabolism & Balance Blood Sugar
  • 10 Ways Your Gut Bacteria Affect Your Metabolism & Blood Sugar

Metabolism & Blood Sugar 101: The Basics

Metabolism Definition

“Metabolism” is a buzzword in the health and wellness world that gets thrown around like “clean eating” or “gut heath,” but what does “metabolism” really mean?

Your metabolism refers to the process by which your body converts the food and water you consume into energy for immediate use, or to be stored for later—basically metabolism is how efficiently your digestion (and absorption) of nutrients work.

Many people just think metabolism means how you store fat or burn calories, but it is SO much more.

Your metabolism is responsible for conducting all the cellular processes in your body required to maintain life, as well as absorbing, digesting and utilizing your nutrients.

You are what you digest. If you have a leaky gut, bacterial overgrowth, dysbiosis, low stomach acid or other signs of GI distress (frequent gas, bloating, constipation, skin breakouts, allergies), then your body’s ability to convert carbohydrates, proteins and fats into energy is challenged.

Enter: Your blood sugar levels.

Blood Sugar Definition

Your blood sugar is a blood marker metric that reflects how well your metabolism is working.

Blood sugar is the concentration of glucose (energy) in your blood, and is the fuel your metabolism uses to drive evry single bodily process. In short: Your body needs sugar, or glucose (energy from the food you eat), to function.

Blood sugar itself is not a bad thing, however uncontrolled blood sugar–either too high or too low–is not a good thing.

Uncontrolled blood sugar is the reason why more than 100 million American adults have pre-diabetes and diabetes, why more than 70% of Americans “need” coffee to function, and why you got sleepy in 4th grade math class after your PB & J, Dorito chips and Oreo cookie at lunch time.

Ideal Blood Sugar Levels

Ideal blood sugar levels (measured via blood work or a reliable glucometer should fall between:

Fasting Blood Sugar: 70-140 mg/dl

Beforemeal normal sugars are 70–99 mg/dl

Post-meal or “postprandial” sugars (within 2 hours after a meal): Less than 140 mg/dl.

Generally, if your blood sugar levels stay within this range, you will feel fairly steady in your energy levels, mental clarity and appetite throughout the day—not too hungry (or hangry), and not too stuffed or in a food coma.

In the case of episodes of “blood sugar imbalance,” however, your blood glucose trends out of range. You do not have to be diabetic or “insulin resistant” to experience changes in blood sugar throughout the day.

Understanding the Blood Sugar Imbalance Conundrum

When we have too much blood sugar in our body (hyperglycemia), our cells don’t know what to do with all the extra energy, and have difficulty using and absorbing it into our body, often resulting in high blood sugar, metabolic syndrome, insulin resistance, fat storage, unwanted weight gain or weight loss, and/or blood sugar imbalances (brain fog, headaches, trouble concentrating).

If we have too little blood sugar in the body (hypoglycemia), we equally suffer from blood sugar and metabolic imbalances, like shakiness or feeling hangry before meals, headaches, low energy, sleepiness, light headedness or fainting, insatiable appetite, excess sweating, and/or anxiety. Ideally, we want a balance of blood sugar throughout the day—a body that can utilize and optimize every single nutrient we eat without ending up with too much sugar in the bloodstream, or starved for more nutrients due to malabsorption, deficiencies or too little fuel.

The #1 Way to Boost Metabolism & Balance Blood Sugar

How to balance blood sugar and optimize your metabolism at the same time?

IT STATS IN YOUR GUT!

As simple as it may sound: Look to the gut!

By focusing first on supporting your digestive health, along with a nutrient dense diet and essential lifestyle factors (like sleep, stress management and exercise), you optimize your metabolism and blood sugar to utilize the fuel you consume.

Don’t believe me?

Here are 10 Ways Your Gut Bacteria Affect Your Metabolism & Blood Sugar…

10 Ways Your Gut Bacteria Affect Your Metabolism & Blood Sugar

People who gain weight easily or have a “slow metabolism” have a less healthy gut bacteria.

 While the main cause of unwanted weight gain is an excessive energy intake, the wide variation between individuals in microbiota composition and energy-harvest abilities highlights the often “missing link” in why some people gain unwanted weight more easily than others or have a “slower metabolism” than others.

For instance: Differences in the abundance of Bacteroidetes and Firmicutes in the microbiota’s of obese mice vs. normal controls have demonstrated that there is an enhanced abundance of Firmicutes and reduced Bacteroidetes  (1) (Firmicutes is correlated with weight gain, whereas Bacteroidetes is correlated with lean individuals).

This same association was observed in followup nutrition-intervention study involving obese human subjects followed by an increase in Bacteroidetes with weight loss (2). Levels of Bifidobacterium species are also higher in leaner people vs. overweight and obese ones (3, 4).

Poo and gut bacteria are different in lean people compared to obese people. Mice that receive gut bacteria transplants from overweight humans are known to gain more weight than mice transplanted with gut bacteria from normal weight subjects, even when the mice are fed the same diet (5). These findings have been observed in multiple studies as well: Transplant of the microbiota of lean subjects into subjects with metabolic syndrome via FMT (fecal microbial transplant) improves insulin sensitivity, metabolism and increase microbiota diversity and abundance (6-9). For instance, another study in humans showed that when obese individuals diagnosed with Type 2 Diabetes underwent a stool transplant from lean healthy donors, they experienced significant increase in insulin sensitivity (as measured by the median rate of glucose disappearance) and fecal microbiota diversity, and decrease in fecal SCFA in the allogenic versus autologous group (10).

 

The Standard American Diet’s influence on metabolism is not just about calories or sugar. You know eating fast food and processed foods is “not good for you.” However, what many people in the diet and health industry don’t realize is the reason why our Westernized diet is “not” good for us goes far beyond just eating too many calories or sugar. The Western diet promotes inflammation that causes both structural and behavioral changes in the microbiome. When our gut bugs encounter indigestible, inflammatory foods it increases our gut bugs’ expression of “virulence factors” (pathogenic and destructive effects) and inflammation througout our gut microbiome as a whole (11-13), resulting in a decrease in metabolism as our gut fights to cope with stress.

4. Gluten-free, Keto or Vegan diets aren’t the “cure all” to boost metabolism or blood sugar.
The “Western diet” doesn’t just refer to Big Mac’s and French fries either. It can also include gluten-free processed foods, high fat “dirty” Keto diets (without enough greens) and meat free vegan diets, high in soy, grains and beans (and not enough vegetables). In other words: Not enough gut-friendly foods (i.e. fiber, essential proteins, vegetables and non-inflammatory fatty acids). High inflammation, nutrient deficiencies or poor absorption of nutrients are all gateways to metabolic disturbances that stem from an unhealthy gut microbiome. For example, many people who follow a standard gluten-free diet have lower levels of beneficial bacteria, often due to the fact they are eating gluten-free Mac & Cheese, gluten-free pizza crust and gluten-free Cheerios (14). Similarly, the ketogenic diet boasts wonderful short-term impacts on the gut microbiota, especially those with cognitive impairments like epilepsy and Alzheimer’s (15, 16). However, high ketones as well as lack of short chain fatty acids and fermentable fibers have also been shown to invite candida (yeast) or the overgrowth of other bacteria (17, 18). It’s also important to note that low carb diets may inhibit short-term therapeutic protocol that will actually get rid of the Candida and conditions like SIBO since fermentable carbohydrates are essential for bringing out the targeted unwanted yeasts and bacteria that supplements are used to treat. As for meat-free diets, similar decreased fecal microbial diversity has been found in both vegans and metabolic syndrome patients (19), suggesting that Westernized vegan diets may result in a decrease of beneficial bacteria if the diet is not inclusive to enough vegetables. (Fact: only 1 in 10 Americans eats the recommended number of vegetables, 20). Additionally, without enough beneficial bacteria, amino acid metabolism (protein digestion) is significantly altered (21). This could explain why many meat-free advocates actually feel worse (not better) if they do eat meat, often reporting they feel “heavy” or like they can’t digest their meat (it could be lack of healthy gut bacteria and low stomach acid). This also explains why why high protein diets are often connected to inflammation (22, 23) in headline news (translation: it may no actually be the protein but lack of beneficial bacteria to digest the proteins).

You can reverse a slow metabolism by altering the gut microbiome. 99% of all diets fail. Why? The answer could be in the microbome. A study on yo-yo dieting and weight regain following a diet in obese mice found that their gut microbiota naturally shifted in a positive direction during weight loss; however, in the aftermath, researchers concluded that when the post-obesity gut is not continually supported to become healthier in the stages following weight loss (such as prebiotic fiber, probiotics and a non-Westernized diet), the study subjects eventually re-gained weight. Additionally, when researchers introduced antibiotics (i.e. “gut stressors”) into the mix, weight re-gain also accelerated (24).

Metabolism is not just about weight gain or weight loss. It is also about how well your body absorbs and uses the glucose (carbs), proteins and fats you eat. A person can be skinny, skinny fat or lean with horrible digestive issues (like IBS, malabsorption and sill have metabolism “issues.” Metabolism is really a matter of blood sugar regulation and how your body optimizes the amino acids (proteins), fatty acids (fats), glucose (carbs) and micronutrients (vitamins and minerals) you eat. Ultimately, the ability to use and/or store calories from food is greatly impacted by gut microbes (94). Have you ever wondered why cruciferous veggies, plants and berries are hailed the “antioxidant” superheroes against cancer? Answer: They encourage fermentation in the gut and beneficial bacteria (25).

 

High fiber diets are linked to remission of Type 2 Diabetes. A Finnish Diabetes Study (26) showed that people who ate more fiber had more of an anti-inflammatory chemical in their blood called indolepropionic acid (which is made by gut bacteria) and were also less likely to go on to get type 2 diabetes. For the study, researchers put 27 people with type 2 diabetes on a very high-fiber diet (37+ grams/day) and followed them for 12 weeks, measuring changes to their blood sugar, and also to their gut bacteria. hey compared subjects with 16 others who also had type 2 diabetes but received standard advice on exercise and eating right for diabetes along with a diet that had roughly same number of calories, but only 16 grams of fiber—about what American adults average. Both groups also took acarbose, a medication to help manage their blood sugar; and if anyone was taking insulin, researchers monitored and controlled it regularly. By the end of 12-weeks, noth groups improved, but the group on the very high-fiber diet was healthier than the group receiving standard care. They had better control of their blood sugar, lost a bit more weight, and about 90% of them sent their Diabetes into remission with a Hemoglobin A1c reading under 7%, the target recommended by the American Diabetes Association — compared with just 50% of the group on a standard diabetes diet. Researchers concluded that the high fiber from a wide variety of food sources, fertilized the growth of 15 different strains of bacteria that produce certain short-chain fatty acids—required for optimizing metabolic function, blood sugar and blocking out bad bacteria.

 

Gut bacteria produce secondary bile acids that affect blood glucose levels., Well-known links to blood sugar imbalances in conventional medicine include history of antibiotic exposure, poor diet, sedentary lifestyle and stress. However, no one ever really explains little why these things affect blood sugar. Why do “stressors” like antibiotics, granola bars, sitting at a desk or lack of sleep affect blood sugar stability? Research suggests that bile acid disruption may be at play. Bile acids are digestive aids produced in the liver that help facilitate digestion and absorption fuel in the small intestine, as well as regulate cholesterol balance. In a 2018 study (27), researchers examined what happened to mice with dysbiosis (bacteria imbalances) when they were administered with antibiotics, compared to non-antibiotic treated mice. In the dysbiotic mice, they discovered that the production of secondary bile acids by gut bacteria decreased, as well as the reserves in their liver/ However, when secondary bile acids were supplemented at the same time as antibiotic administration, the mice’s blood glucose and blood triglyceride levels recovered. Researchers concluded that the secondary bile acid produced by intestinal bacteria affects sugar (glucose) and lipid (fatty acid) metabolism of the host.

 

Probiotics lower blood sugar. In one clinical trial (28) published in Lipids in Health and Disease, researchers gave volunteers a daily shake containing Lactobacillus acidophilus and Bifidobacterium bifidum. After 30 days, participants showed a significant balancing of glucose levels (nearly a 40% change from their initial readings: 191.11 to 116.78 mg/dL) while the placebo group, who received a shake without the beneficial microbes, showed no change. Countless other studies support these findings, with probiotic bacteria improving Hemoglobin A1C (diabetes’ marker), fasting insulin and glycemic control in subjects compared to placebo controls (29, 30, 31)

 

Ketogenic diets & fasting may boost metabolism and improve blood sugar balance in some people because they shift the microbiome
Ketogenic (Low carb, high fat) diets, fasting and intermittent fasting (12-16 hours between meals) are popular dietary fads in health and nutrition world that often have two divided camps: (1.) One camp of people claiming keto and fasting is the “panacea” for every health aim imaginable—from weight loss, to blood sugar regulation, brain function and energy; (2.) Another camp complaining “keto and fasting don’t work for me!” Who is right? Answer: There is no one-size-fits-all approach to the “best” nutrition strategy for you. Instead, the real answer may lie in how a particular diet effects your gut microbiome. For those whom experience great blood sugar and metabolic success on keto and/or fasting, research points to the fact that this may be because these folks’ microbiomes benefited from the switch.

 

Intermittent fasting has been shown to preserve gut homeostasis (balance), strengthen the gut lining and reduce bacterial abundance in the gut (32). It is a style of eating that humans have done since the beginning of time and for good reason—food was not always available at the local Whole Foods. Hypothetically, fasting is also particularly great for those with underlying gut conditions like SIBO (small intestinal bacterial overgrowth) or intestinal permeability prior to a regular fasting practice. Since fasting gives the body a break to rest and repair from the work of digestion, many people report experiencing initial improvements in gut health, blood sugar balance and metabolic function. Likewise, a ketogenic diet may work similarly for some folks as fasting and intermittent fasting (33, 34), particularly in those with former dysbiotic or overgrown bacteria prior to “going keto”—at least in the short-term. Since ketogenic diets greatly restrict carbohydrates, diet adopters may naturally deprive overgrown gut bacteria or yeast of certain sugars and starches that once fed their unhealthy gut bacteria foods in favor of more fats, greens and proteins instead. The result? An initial shift in their own gut bacteria—without even trying, along with improved insulin sensitivity, blood sugar balance and weight loss.

 

On the flip side, for those who experience negative side effects from one or both of these dietary strategies, the opposite may be true as well—a shift in the gut microbiome may happen initially, however since fiber rich, whole food carbs also help feed beneficial gut bacteria, if these gut bacteria are deprived from carbs too long, negative side effects may occur, including increased dysbiosis and inflammation, decreased short chain fatty acids and altered bowel habits (35, 36). This side effect is not just limited to high-fat ketogenic diets either; high protein, low-carb diets also produce similar results, decreasing fecal cancer-protective metabolites and increased concentrations of hazardous metabolites (37). Additionally, fasting can be detrimental for individuals who have sluggish GI motility already when faced with a high caloric load at once on their body during their feeding periods, digestive difficulties may ensue; as can lack of soluble carbohydrates in particular that help “push” food through the GI tract and have a soothing effect on the gut lining. Other research supports the fact that in some people, long term high-fat diets actually feed pathogenic gut bacteria (37). In the study, scientists designed an artificial intestine and used donor fecal matter to recreate the bacterial environment found inside the human colon. Next, they added in a typical “Western diet,” followed by a therapeutic intervention ketogenic diet (rich in fats; no carbs or protein), and measured the composition of metabolites before and after the change in nutrients. Their findings? The ketogenic-like diet increased the prevalence of certain strains of bacteria that metabolize fatty acids and lowered the number of good bacteria needed to break down protein and carbs, revealing potentially have negative health consequences on the host. The ultimate conclusion? While much research still remains to be done, keto and fasting may work better for some folks more than others, dependent on their unique gut bacterial profile before, during and after the dietary intervention.

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