Have you started intermittent fasting recently only to feel like all you can think about is your next meal? If you’re struggling to make it through your fasting window without experiencing pronounced hunger, fatigue, weight gain, shakiness, brain fog, or mood swings, you may be dealing with an underlying health situation that needs your attention.

Intermittent fasting (IF) is one of the most beneficial, life changing health practices that I’ve come across in all my years practicing medicine. It has led to profound health changes in my patients, resulting in the reversal of chronic symptoms and diseases. Intermittent fasting helps the body enter a state of fat adaptation and self-cleansing that no medication, supplement, or tool can accomplish. Fasting is phenomenal. To learn more about the benefits, check out my previous blog post.

Sometimes, however, IF proves to be challenging and more complicated than it should be. Some people experience tremendous hunger, fatigue, feel shaky, gain weight, or go through mood swings when they try to shrink their eating windows. These symptoms are relatively normal in the first few weeks of beginning an IF routine but when the symptoms drag on, when they are severe, and when the thought of fasting produces anxiety or fear, it usually points to a deeper problem. Symptoms are red flags that need to be listened to, and that includes during any attempts to fast. Always make sure you’re working with a functional doctor who can guide you when you try any fasting routine; you never know how you’re going to react and what your body is going to do as a result.

In my experience, there are 4 main reasons people can’t successfully intermittent fast. Read on and check out my latest video to learn more.




  1. Food Sensitivities

The prevalence of low-grade food allergies and intolerances has risen at an alarming rate over the past two decades. Unfortunately, most people are completely unaware that the foods they are consuming may be having a negative impact on their health. For me, gluten is the main food offender. If I consume even small amount of gluten, I experience severe GI symptoms, brain fog, depression, and joint pains for several days. It took me years to figure out that it was the food I was eating that was making me sick. For my son Mason, it’s corn. Despite having him on a very clean, gluten-free diet, his skin broke out in a severe case of eczema at age three. We could’ve spent years trying treatments, but we started by addressing his diet and found that he simply can’t tolerate corn. Once we eliminated that food from his diet, the eczema completely went away and hasn’t come back. The important thing to keep in mind is that what may be a healing, nutrient-dense food for one person, might be a true health roadblock for another.

Some of the most common food sensitivities we see are:

  • grains and pseudograins (rice, wheat, oats, quinoa, corn, buckwheat, millet, rye, etc.)
  • dairy
  • gluten (a protein complex found in wheat)
  • soy
  • eggs
  • nuts
  • legumes (beans, lentils, peanuts, etc.)
  • processed sugars

The best way to identify whether you have food sensitivities is to try an elimination diet for at least 30 days. During this time, you would eliminate all of the foods that are listed above, as well as any foods you may think are questionable in your own diet. For some people, this might be chili peppers or bell peppers, mushrooms, onion, or certain types of animal protein such as chicken or turkey. After going at least 30 days without the potential food triggers, you would then reintroduce foods one at a time in a systematic order to ensure that you’re catching the culprit.

If elimination diets seem too tedious, there are some great food sensitivity panels you can have run via blood by Cyrex Labs. They typically run upwards of $500, so proceed as you are able to.

When patients are dealing with unidentified food sensitivities, it can cause the body to become inflamed and literally stressed out at a cellular level. When our cells are stressed and inflamed, they will not be able to adapt to using fat for fuel. They will be stuck using glucose, which will make fasting very challenging. It’s important that if you’re not seeing progress with intermittent fasting, or feeling more symptomatic than what you know is normal for your body, that you address potential food triggers in your diet and eliminate them.


  1. Environmental Toxins

Most environmental toxins are fat soluble which means they accumulate in our body’s fat. Our cells are surrounded by a 2-layer membrane of fat. In other words, toxins accumulate in our cellular membranes, often resulting in more cellular inflammation. Stressed and inflamed cells will not adapt to using fat for energy. If you’re fasting and noticing that you’re extremely tired, have brain fog, feel mentally sluggish, or find yourself experiencing bizarre mood swings, you may be dealing with cellular toxicity.

Our environment is full of toxins…we can’t escape this fact. Heavy metals are a huge concern for nearly everybody. Mercury is found in amalgam fillings and fish; aluminum is found in cookware, deodorant, and vaccinations; lead is passed down generationally through our mothers in utero; cadmium is in the air from cigarette smoke, and the list goes on. Additionally, we’re literally inhaling, eating, and drinking pesticides and herbicides daily due to the heavy spraying on our crops, in parks and communities, and in our own gardens (i.e. Round Up). Mold has also become a growing problem in a vast majority of homes. As mold grows, the spores travel like pollens and can cause extreme illness in susceptible people. Literally everywhere we go, we’re being bombarded with toxins.

The good news is that our bodies are strong and capable of purging these toxins through our elimination organs: kidneys, skin, liver, and gut. The bad news is that, for many of us, these organs are overworked and sluggish and can’t adequately handle the toxic overload. One of the biggest problems we see with intermittent fasting difficulties is the deeper issue of cellular toxicity. As we begin to fast, toxins stored deep within fat cells begin to get liberated as our body goes through a process called autophagy. In healthy people, this is amazing and profoundly healing, but in people who are dealing with significant cellular toxicity, it can be really tough because the detox organs are compromised and unable to properly eliminate the toxins.

During fasting, the cells dump toxins, but if those toxins have nowhere to go, this leads to a marked increase in symptoms and can lead to “autointoxication,” a form of self-poisoning. It’s crucial you work with a practitioner when it comes to detoxifying the cells. Make sure you’re working with someone who’s skilled at opening the detox pathways and binding the toxins once they reach the gut for elimination. Once you’ve addressed the toxicity appropriately, fasting should become much easier and something that you’ll actually look forward to.


  1. Hidden Infections

One of the top reasons I see patients struggle with intermittent fasting is hidden infections. These come in the form of viruses, bacterial or yeast overgrowths, or parasites. It’s one of the most overlooked steps in healing, and addressing these infections is crucial, both for intermittent fasting and for living a healthy, thriving life.

“Hidden infections” can be difficult to identify hence the name. Most people are completely unaware that they are suffering from an infection because they don’t experience the typical acute fever or flu-like symptoms. Deep down, these infections subtly suppress the immune system, add to the toxic burden, and cause systemic inflammation throughout the body. Needless to say, this will make it very difficult to intermittent fast successfully.

Hidden infections are one of the most common underlying causes of chronic disease. When they are properly dealt with, I witness tremendous improvements with my patients. In fact, hidden infections are so prevalent, I recommend that most people go on an herbal “deworming,” or antimicrobial protocol, at least once, if not twice, per year. For patients who are chronically symptomatic even after finishing an appropriate antimicrobial protocol, testing for viruses can be vital. If you are struggling with intermittent fasting, it’s likely that you have a hidden infection.


  1. Nutritional Deficiencies

When we ask our bodies to fast, we’re counting on the nutrient reserves that we’ve acquired through years of good eating to get us through our fasting windows. If we haven’t addressed the issues listed above, however, or we’ve had poor nutrition for a prolonged period of time, we simply won’t have the nutrient reserves to get us through a fast.

Whenever we’re fasting, it’s important to maintain a healthy, well-rounded diet during the times that we are eating, and address any potential nutrient deficiencies so that we don’t do more harm than good. If the cells are missing nutrients, they won’t be able to adapt properly, and we’ll feel unfit to fast.

Some of the most common nutrient deficiencies include magnesium, b-vitamins, and vitamin D. One of the reasons patients struggle with nutrient deficiencies is a compromised digestive tract. Again, if there are lurking infections, toxicity at the cellular level, or if you’re being bombarded by a food trigger on a regular basis, the integrity of the digestive tract will suffer and nutrient deficiencies will follow.


Are you struggling with intermittent fasting? Have you addressed any of the factors listed above with success? Let me know in the comments below.