4 Root Causes of Low Mood & Depression


Low mood and depression are increasingly at an alarming rate in today's modern society. The Center for Disease Control shows 10% of people suffer from depression, but in clinical practice people struggle with low mood at much higher rates in today's constantly connected world seemingly fuelled by processed foods. The World Health Organization has estimated that by the year 2050, one-third of the global population will suffer from either anxiety or depression. This is a moind-boggling statistic. How is this possible? Why are we more prone to depression today than in generations past? As with any complex condition, multiple underlying factors conspire to create an environment where low mood and depression can thrive. Let’s look at a few common root causes to better understand how things go wrong at a cellular and hormonal level. 


Today, 75% of the North American population are classified as overweight or obese. While the annual consumption of processed and simple sugars has dropped a little over the past few years, it's still incredibly high at 100-140 lb. of sugar per person. Combined with the over-consumption of processed carbs and alcohol and you've got five of the top six foods in the American diet; desserts (grain-based), breads, processed chicken, soda pop and energy drink, alcohol and pizza. This leads to an excessive caloric intake, which is further exacerbated by these hyper-palatable foods, meaning the cycle continues over and over again. When your cells are constantly flooded with excess energy, they eventually say "enough is enough" and refuse to take in more energy. This is the state of insulin resistance and further down the road diabetes (type-2). 

How does this relate to mood? Research from Scandinavia has uncovered a clear association between elevated HbA1c - a three-month average of you blood sugar levels - and insulin levels with increased risk of depression. They found that young men with insulin resistance were three times more likely to suffer from severe depression.(1) Another study in Diabetes Care of over 4,000 people showed depressive symptoms were highly associated with higher fasting and 30-minute insulin levels.(2) The authors specifically noted that antidepressant medications did not alter this association because the medications target neurotransmitters (e.g. serotonin, dopamine) and do not address blood sugar and insulin dysfunction. Improving blood sugars and insulin control is an important first step for reducing your risk for low mood and depression.


Inflammation is another potential root cause of low mood. Low-grade systemic inflammation leads to the over-production of pro-inflammatory cytokines that are also associated with depression.(3) The prestigious New England Journal of Medicine recently published a review of the growing connection between chronic inflammation and the development of today’s most common chronic diseases, including depression.(4) The current medical literature tells us that if you are overweight or obese, you likely have low-grade systemic inflammation.(5) This shouldn't be a surprise, as inflammation is "upstream" of blood sugar and insulin dysfunction. A diet rooted in traditional foods - rich in animal protein, healthy fats and antioxidants - will help to cool inflammation and reduce the damaging effects of reactive oxygen species (ROS) produced during the inflammatory response. Polyphenols found in coffee, dark chocolate (even red wine!), as well as vegetables are great sources of anti-inflammatory polyphenols. Extra-long chain omega-3 fats DHA and EPA also exert powerful anti-inflammatory effects and a poor omega-3 to omega-6 fats ratio is also associated with a chronic stress state and increased risk of depression.(6)


The gut microbiota - commonly referred to as your microbiome - plays a key role in your mental health through its constant communication with the brain via the vagus nerve. Key neurotransmitters targeted by medications for improving symptoms of depression – serotonin and dopamine – are actually produced in the greatest concentrations in the gut (not the brain). This gut:axis is highlighted by research showing that if you are overweight, you're at much greater risk of poor zonulin function, a key molecule that regulates gut permeability.(7) Poor zonulin function leads to symptoms of a leaky gut, leading to a pro-inflammatory environment that creates the cytokine storm that contributes to low mood and depression. You don’t need to be overweight to suffer from leaky gut. If you travel across multiple time zones, consume alcohol excessively, or chronically rely on NSAIDs – non-steroidal anti-inflammatory drugs – like ibuprofen and naproxen you'll be much more prone to leaky gut and chronic worsen inflammation.(8,9) A dietary approach rooted in traditional foods - animal protein, healthy fats, vegetables and unprocessed carbohydrates - will help to keep blood sugar levels balanced and support a healthy gut microbiota, thus keeping systemic inflammation and low mood at bay.  


Movement is a critical component of mental health and wellbeing. Long, busy workdays make it difficult to find time to exercise, however it should be a foundation of every mental health plan. A recent meta-analysis of 92 studies on more than 4,310 people showed that light to moderate exercise significantly reduced the incidence of depression.(10) Try adding 15-20 minute walks at lunch or the end of your day to increase your activity level.

Strength training can also play a key role in mental health. Basic movements like squatting, lunging, bending, pushing, and pulling are deeply engrained in our DNA and exert tremendous positive benefit on multiple systems of the body: improving blood sugars and insulin, reducing inflammation, boosting testosterone (low levels have been associated with depression), and supporting healthy gut flora. If you’re not active, start slowly with 10-20 minutes of strength training 2-3 times weekly and focus on bodyweight type movements.

There is no “magic bullet” to fix depression. It’s a complex multi-factorial condition that is impacted by numerous systems of the body. From a biochemistry and physiology standpoint,  addressing root causes like blood sugar and insulin dysfunction, chronic inflammation, dysbiosis and leaky gut and maintaining an active lifestyle are great places to start so you can raise the playing field. (It's also important to consult a qualified mental health professional to address the underlying emotional root-causes). Take control of your mental health by making the small changes to your nutrition, movement and lifestyle so you can get back to feeling your best. Many people and athletes alike experience low mood and depression, you're not alone.

Dr. Marc Bubbs ND, CISSN, CSCS

Want to learn more? High blood sugar and insulin levels are strongly associated with depression. Listen to diabetes expert Dr. Jason Fung MD in Episode #15.




1. Timonen. M et al. Insulin resistance and depressive symptoms in young adult males: Findings from Finnish military conscripts. Psychosom Med 69(8):723-28.

2. Pyykkonen AJ et al. Depressive symptoms, antidepressant medication use, and insulin resistance: the PPP-Botnia Study. Diabetes Care. 2011 Dec;34(12):2545-7.

3. Felger J, Lotrich FE. Inflammatory cytokines in depression: neurobiological mechanisms and therapeutic implications. Neuroscience. 2013 Aug 29;246:199-229.

4. Emerging Risk Factors Collaboration. Diabetes mellitus, fasting glucose, and risk of cause-specific death. New England Journal Medicine, Mar 2011;364;9:328-341.

5. G. S. Hotamisligil, N. S. Shargill, and B. M. Spiegelman, “Adipose expression of tumor necrosis factor-α: direct role in obesity-linked insulin resistance,” Science, vol. 259, no. 5091, pp. 87–91, 1993.

6. Larrieu T, et al. Nutritional omega-3 modulates neuronal morphology in the prefrontal cortex along with depression-related behaviour through corticosterone secretion. Transl Psychiatry. 2014 Sep 9;4:e437.

7. Moreno-Navarrete JM et al. Circulating zonulin, a marker of intestinal permeability, is increased in association with obesity-associated insulin resistance.. PLos One 2012;7(5):e37160.

8. VanWijck K et al. Aggravation of exercise-induced intestinal injury by Ibroprofen in athletes. Med Sci Sports Exerc. 2012 Dec;44(12):2257-62.

9. Matsui H et al. The pathophysiology of non-steroidal anti-inflammatory drug (NSAID)-induced mucosal injuries in stomach and small intestine. J Clin Biochem Nutr. 2011 Mar;48(2):107-11.

10. Rebar A, et al. A Meta-Meta-Analysis of the effect of physical activity on depression and anxiety in non-clinical adult populations. Health Psychol Rev. 2015 Mar 5:1-78.

Brain Fog: Symptoms, Causes & How to Naturally Treat It

Have you ever struggled with mental performance at work?

Have you ever felt like your brain is stuck in slow motion—like a fog is settling inside your head? You don’t feel quite right at your desk, but you can’t put your finger on the reason why.

Brain fog is a clinical symptom, which is characterized by an inability to focus or think clearly, memory loss (short-term and long-term), difficulty learning new tasks, and a possible feeling of being more discouraged than normal.

If you can’t think clearly, have memory trouble or difficulty learning, you’ve got brain fog.

The tricky aspect of brain fog is that it’s a common symptom, which can arise from many different root causes.

What Causes Brain Fog

The following is a list of the most common causes. Uncovering which items may apply to you can help clear your mind and reboot your focus and concentration. Here are the major causes of brain fog.

Too Much Connectivity

Technology is incredible. It allows us to communicate at a record pace and push the limits of productivity in all domains. However, too much technology can be a big problem. Today, the average person checks Facebook at least 14 times a day, and over 50% of the human race uses more than two social-media apps daily. (1)

It’s information overload for your brain. As a result, your workday is likely to be too fragmented; the average person spends 2-3 minutes on each task, bouncing around from one task to another all day long.

The Fix: Research shows that concentrating your work into blocks of at least 10-12 minutes can dramatically increase the brain’s efficiency and reduce stress-induced fatigue. (2) Or, try a total digital detox!

Your Blood Sugars Are Out of Balance

If you eat a high-carb diet, crave sugar, or are overweight, your body’s ability to produce regular blood sugars may be compromised. The worse your blood-sugar control is, the greater the likelihood for big swings (highs and lows) throughout the day.

High or low blood sugar levels are linked to depression and brain fog.

Blood-sugar lows leave your brain sluggish and stuck in the mud. Research shows that high blood-sugar levels multiply your risk of depression by 2.5, and your cognitive decline by 7. (3,4) In fact, the reverse is also true. If you struggle with depression, it significantly increases your risk of blood-sugar dysfunction; each one makes the other worse! (5) (Experts aren’t sure if it’s the ‘chicken or the egg.’)

The Fix: Reduce your intake of starchy carbohydrates; breads, pastas, potatoes, rices. A Paleo diet is the ideal plan for a low-carb, high protein and fat diet to restore blood sugar balance. Also be sure to eliminate all added simple sugars.

You’re Going Gluten Crazy

A Paleo diet is free of all grains. Specifically, it is void of public enemy #1: gluten. Gluten is a group of proteins found in wheat, rye, and barley, which can exert detrimental effects on your gut and brain. If you regularly consume too much gluten, it damages the lining of your intestinal tract, creating hyper-permeability or a leaky gut. (6)

While most doctors would agree that this damage occurs in celiac patients (i.e., people with 100% gluten intolerance), the new research shows damage actually occurs in all of us. Some can tolerate more gluten than others, but damage still occurs.

Of course, if you have a leaky gut, we now know that you are likely to also have a “leaky brain”—which negatively impacts cognitive function. If you struggle with brain fog and also have digestive problems (e.g., gas, bloating, abdominal discomfort, and constipation), fix your leaky gut to fix your brain fog.

The Fix: Eliminate all gluten from your diet for 4 weeks so you can see for yourself the impacts gluten has on your brain and cognitive function. Dairy products can also cause a similar reaction, called cross-reactivity, to gluten so you’re best to eliminate all dairy for one month as well. This will help reduce the damage to your gut wall and allow you digestive system time to heal.

You’re Anemic

Oxygen is what gives you life, and the hemoglobin protein found in your red blood cells is responsible for carrying it around your body. Hemoglobin needs iron to bind oxygen and fuel all the cells in your body (and your brain!). If you struggle with low iron, you’ll likely also struggle with brain fog.

The Fix: Great ways to start correcting low levels include following a Paleo-based diet and eating iron-rich animal proteins like red meat, wild game, and seafood. The research shows a strong association between good iron status and cognitive function, so boost your iron intake to boost your brain function. (7)

Your Body Is On Fire

The immune system’s hallmark response to an infection or injury is inflammation. Inflammation is caused by the release of cytokines and histamines (i.e., powerful pro-inflammatory weapons that your immune system uses) to kick up inflammation and try to heal your body.

If you suffer from an undiagnosed chronic infection (or you’re overweight or out of shape), your levels of systemic inflammation will be elevated. The histamine and cytokines released in this state result in brain inflammation, which may slow cognitive function and memory. (8) This “brain on fire” scenario can leave your mental function chronically stuck in neutral—and you searching for answers.

The Fix: Inflammation can arise from many root causes, but a great place to start is to correct blood sugar imbalances (i.e. adopt a low-carb Paleo diet) and any digestive problems like gas, bloating, IBS, etc. Removing dietary triggers like gluten and dairy is a great place to start.

Not Enough Quality Sleep

During deep sleep, your brain and body recover. You rebuild and restore optimal function from head to toe, so you can start fresh again the next day. The problem is that most people don’t get enough sleep. Americans average about 6.5 hours of sleep per night—a far cry from our grandparent’s generation, who usually tucked in for 8 hours per night.

Too much technology, caffeine and alcohol all contribute to a poor night’s sleep.

However, it’s not just total sleep time that impacts recovery; it’s also sleep quality. Your capacity to get into a deep, restorative sleep is impaired by things like caffeine and alcohol. They also impair growth-hormone release, which means you won’t be able to efficiently recharge your brain or body. (9)

The Fix: To improve sleep quality, make sure to disconnect from all your mobile devices at least one hour before bed and aim to get to sleep before midnight for the next four week. Remember, to boost recovery and clear brain fog, you must also skip your afternoon coffee or glass of wine in the evening for the next months to restore mental clarity and performance.

Too Much Training

Exercise is phenomenal for boosting brain function and health, but you can get too much of a good thing. If you’re a CrossFit, running, or boot-camp class addict (and you’re not periodizing or planning your training regime throughout the month), you could be overtraining. Classic symptoms of overtraining include low mood, increased muscular pain, increased likelihood to catch colds and flus, and decreased cognitive capacity. (10)

The excessive inflammatory response (discussed above) has a significant impact on both your body and brain.

The Fix: If you’ve been pushing your limits on the training front, make sure to taper off the last week of every month by reducing your training volume (i.e., how much you train) and training intensity (i.e., how hard you train) to allow your nervous system (and your brain) the chance to recover.

Early Menopause

Menopause is officially diagnosed when you’ve gone for 12 consecutive months without menses. The most common age range of menopause in American women is 48-54, yet for some, it can start at a much earlier age. A hallmark symptom of menopause is brain fog, but for years, doctors dismissed this claim. However, new research is uncovering a strong association between menopausal transition and memory complaints. (11)

The Fix: Researchers aren’t sure why this type of brain fog occurs. (Is it genetics, lifestyle factors, or hormonal shifts?). Nevertheless, your best bet is to mitigate factors that commonly aggravate the shift into menopause like a high caffeine, sugar, alcohol intake. During menopause, your liver and digestive system clear excess estrogens, therefore limiting the burden on these organs typically helps reduce menopausal symptoms in clinical practice.

Side Effects of Drugs

People often forget to include drugs they’ve been taking for years on medical intake forms because they’ve become so second-nature to them. However, when another drug or supplement is added into the mix, interactions can take place that lead to a whole host of negative side effects, including brain fog.

The Fix: If you’re currently experiencing brain fog and have recently added any new medications or supplements, talk to your doctor about potential interactions that can impact cognitive function.

If you’ve been struggling with low energy, irritability, headaches, trouble concentrating, or poor memory, then brain fog may likely be the culprit. The root cause of brain fog is multi-factorial. However, by addressing the fundamentals of diet, exercise, and lifestyle factors (e.g., sleep quality and “screen” time), you can help clear the clouds between your ears. It will get you back to feeling focused, sharp, and creative—at work and play.

Dr. Marc Bubbs ND, CISSN, CSCS


Enjoyed this article? Check the podcast interview with gut expert Mike Mutzel to upgrade your brain game!