Should I Exercise While on the GAPS Intro Diet?

This is a common question from those who are just starting the GAPS introduction diet. The first couple phases of the introduction diet consist of pretty much nothing but broths, well-cooked meats, a little well-cooked vegetables as tolerated, and healthy fats and herbal teas. Depending on what your body can tolerate eating at first, which may not be much, it does not always provide a significant caloric intake.

What is happening in your body during the introduction diet? Several things:

1. Herxheimer Reaction. During the introduction diet, most people who are doing the diet to heal significant health problems will be experiencing a Herxheimer reaction, which is a temporary worsening of symptoms due to die-off of harmful flora. Symptoms may include fever, nausea, diarrhea, constipation, flu-like symptoms, headache, etc. For myself, who was a chronic-fatigue profile with yeast overgrowth, I experienced about 10 days of mild "intoxication" symptoms. As crazy as that sounds, it is actually possible for the brain to become "drunk" from all the toxins being released from flora die-off (See Gut and Psychology Syndrome by Dr. NCM, pages 50-53; see also multiple scientific studies/articles on "auto-brewery syndrome" here; and an interesting case report here.). I felt slightly dizzy, befuddled in my thinking, and slightly blurry of vision. Also, my fatigue increased significantly and I had insomnia - my brain just would not turn off to go to sleep. In short, I was pretty incapacitated. Obviously I was an extreme case, but if you are really sick, then chances are it won't be pleasant for the first couple weeks.
2. Sugar Withdrawal. In addition to "herxing," most people will also be having carbohydrate withdrawal symptoms. Yes, sugar is actually biologically addictive to your body, and you will probably get the shakes and grumpies from withdrawal (see this scientific study which found that refined sugar is more addictive than cocaine!). Even if you thought you weren't eating that much sugar before, you would be surprised how much sugar you were feeding your body from grains, starchy vegetables, processed foods, and that daily dessert or soft drink.
3. Metabolic Shifting. Also, the body will be learning how to switch from a carbohydrate-driven metabolism to a fat-driven metabolism. Your body has been primarily processing its energy from carbohydrates, and now it has to learn how obtain its energy primarily from healthy fats. This is a huge shift in how your body functions, and it will likely include some low blood sugar symptoms temporarily until things balance out (see this helpful article about fat adaptation).
4. Physiological Fasting. The first few stages of the GAPS introduction diet are also essentially a form of fasting. During a fast, your body is focusing less on digestion and more on detoxification and rebuilding, and numerous physiological changes occur. For example, during a fast your body cleans out old, worn out white blood cells and replaces them with fresh new ones, thereby giving your immune system a little "reset" (see a study about this here). Intermittent fasting also has an anti-inflammatory effect (see a study here). Of course, your body is working hard to do all this, and you may feel increased fatigue at first (see a helpful article about intermittent fasting here; and a scientific article about fasting benefits here).

So now that you have a greater appreciation for what your body is experiencing during the introduction diet, you should be able to make wiser judgments as to whether maintaining your workout regimen is good for you during this time. For most, if not all people, I would recommend either not exercising during the intro diet, or else, making significant modifications - like walking an easy mile instead of running three. For me personally, I did not have the physical resources to even walk around the block many days during the first couple weeks on the intro diet. Listen to your body. If you are experiencing significant fatigue, and feeling sick and "tapped out," don't push yourself. Let your body rest and do the hard "exercise" of cleansing and rebuilding itself instead. The benefits you are gaining from your diet change are even greater long-term than what you would receive from a regular exercise routine. Don't get me wrong. The body needs exercise. But there is a season for everything, and if you are doing the GAPS diet for health problems, then most likely this is a season for rest, rejuvenation, and energy conservation rather than for energy expenditure through exercise. Once your body is equipped with good nutrition and properly functioning healing mechanisms, there will be plenty of time and energy for exercise later.

Two years after my own journey on the introduction diet, I am now able to do strenuous physical exercise, like heavy yardwork, for hours on end without feeling weak or hungry. Whereas two years ago, exercise would have only been perceived by my body as an added stressor that contributed to further physical breakdown, now my body is now able to respond to physical exertion with beneficial rebuilding and strengthening.