To Fast or Not to Fast?

Wednesday, May 19, 2010 | 0 comments »

By Steve Edwards

As our Nutrition 911 series transitions from drinks to food, what could be more natural than to discuss something in between, like fasting? Most people think that the simplest way to lose weight is to not eat. But if you don't eat, you'll die, which renders this "theory" ineffectual or, at best, short-lived. As we've discussed, we need nutrients to live, and we also need nutrients to transform our bodies from being overweight and out of shape to being svelte and toned paragons of fitness. So what's the deal with fasting? Is it a trend? Is it dangerous? And should you do it?

First of all, fasting isn't a trend. It's one of the oldest therapies in medicine, and its recorded practice dates back thousands of years. But these days, it's hard to peruse the magazines at your local market without being provided with myriad "trendy" fasting options promising health and spiritual enlightenment, and most importantly, weight loss. It's also pretty easy to find literature warning of the dangers of fasting. So let's have a look at its history, benefits, and potential dangers.

If you've read any historical literature, you know that fasting has been around a long time. Many of the oldest healing systems have recommended it as an integral part of a healthy lifestyle. Hippocrates, the father of Western medicine, believed fasting enabled the body to heal itself. Paracelsus, another famous healer, wrote, "Fasting is the greatest remedy, the physician within." Sounds good, but what exactly is it: simply not eating, or using some sort of product you've seen pitched on TV?

By definition, anytime that you don't eat, you are fasting—hence the word "breakfast." Most therapeutic fasts last longer than one night, usually from 1 day to a few weeks. Juice or liquid fasts, while not traditional, are quite common because many of the desired results are achieved without as much stress on the body (see 2-Day Fast Formula® for one option). It's also common to begin a fast by eating cleansing foods, like veggies or soups. A modern fast is often synonymous with a cleanse, or it's a very restricted diet designed to reprogram your body. Most fasts only last a few days. Provided that you stay hydrated, the body can function without food for this long with little stress (though it may not feel like it to you, especially the first time).

Those wanting to participate in the longer and more traditional fasts should have medical supervision, or at least be certain they are in condition to undertake such a venture. While strict nutritionists rarely recommend such things, most alternative medicine practitioners, including homeopaths, naturopathic doctors, and ayurvedic doctors, are well versed at supervising and monitoring patients during fasts. Monitored fasts are almost always safe, but they should be entered and exited with care.

We'll get to the different types of fasts in a moment. First, let's look at 10 reasons why you might want to try fasting or make it part of your lifestyle.

  1. To cleanse your system. Most of us eat more than we should, take in more toxins than we'd like, and are subjected to many other things, like pollutants, that we'd rather avoid. Furthermore, most of us carry around a lot of undigested food in our systems that comes from eating more than we can process. Essentially, a fast will flush these things from your system. Yes, you'll lose weight. But more importantly, your body will run better than it did before.
  2. To change bad habits. When you don't eat, your body craves sustenance and becomes more sensitive to toxins. Most habits are based on cravings, but when you completely change how your system is running, those cravings also change. Coffee is the easiest example. During a fast, your body is too sensitive to tolerate highly acidic substances or caffeine. Coffee will often make you feel terrible during fasting, when ordinarily it has the opposite effect.
  3. To change your health. Many chronic conditions can be treated effectively with fasting, including allergies, anxiety, arthritis, asthma, depression, diabetes, headaches, heart disease, high cholesterol, low blood sugar, digestive disorders, mental illness, and obesity. Fasting is thought to be beneficial as a preventative measure to increase overall health, vitality, and resistance to disease.
  4. To reset your body clock. Fasting gives you a clean slate. Without nutrients, you become more sensitive, and sleep and other patterns change. It's an easy time to revamp your schedule and get your body clock working in your favor.
  5. To bring your body into homeostasis. This is the balance point your body prefers to be at but is rarely achieved with our hectic lives. When the intake of food is temporarily stopped, many systems of the body are given a break from the hard work of digestion. The extra energy gives the body the chance to heal and restore itself—plus burning stored calories gets rid of toxic substances in the body. Essentially, you force your body to work efficiently, and thus bring everything into balance.
  6. For increased mental clarity. Most of us probably first heard of fasting as a spiritual exercise. There are examples of it in most religious texts. It's a great tactic for mental and spiritual rejuvenation because it forces you to focus on important thoughts and frees the mind from everyday clutter. When you are deprived of nutrients, your body—in survival mode—begins to focus on things of true importance.
  7. To make changing your diet easier. When you fast, you become more sensitive to what you put into your body. It's easier to understand how nutrients affect you, and hence how bad foods make you feel worse. The easiest time to change your diet for the better is after a fast. Your body will crave healthy foods. All you need to do is give it what it wants.
  8. To get a better feel for how exercise and diet make your body work. When you take away nutrients, your body can't function as well as it did from a performance standpoint. When you add nutrients back, y ou'll feel your energy increase, and understand how exercise affects you and how your body utilizes nutrients. This understanding can be a great dietary aid. Most of us have a hard time understanding what fats, carbohydrates, and proteins do for us, but coming off a fast, you'll more easily understand their functions, especially if you are exercising.
  9. To improve fat mobilization and physical efficiency. Many physiological changes occur in the body during fasting. Your body turns to stored fat for energy, and this process becomes more efficient under the stress of a fast. Furthermore, the brain, which has high fuel requirements, still needs glucose (sugars converted from glycogen) to perform well. To obtain glucose for the brain, the body finds two sources of fuel, ketosis and muscle, so the body begins to break down muscle tissue during a fast. However, to fuel the brain, the body would need to burn around a pound of muscle a day.

    So we've developed another survival mechanism to create energy that saves important muscle mass, a process called ketosis. Via ketosis, the liver converts stored fat into ketones, which can be used by the brain, muscles, and heart as energy. Those of you versed in the Atkins diet may have a negative association with this process, but "Atkinsers" somewhat abused it. It's another survival mechanism the body has that can be developed and utilized. Where Atkins may have overdone it was by promoting it as a way of life, not a phase toward improving the body's functionality.
  10. To get a forced rest phase. Our bodies do better when we train periodizationally. This is training in phases of intensity, one of which is rest. P90X® is based on periodizational training. Since we tend to skip the rest phase because we feel like we'll regress if we don't exercise (either that or we overly embrace it to the point of not exercising), fasts force a recovery phase because you can't do hard exercise. The most exercise you should attempt is low-intensity movements, like walking, hiking, or easy yoga or stretching. During this time, the body heals its cumulative microtrauma that has resulted from exercise. When you come off a fast, your body will be slightly deconditioned. However, its capacity for conditioning will have increased. This means that once you catch up to the fitness level you were at prior to fasting, you will more easily exceed this level, instead of hitting a plateau.
What are the different types of fasts?
  • The simplest are the "beginner" fasts—Beachbody's 2-Day Fast Formula® is a beginner fast. These usually provide some liquid nutrients, like fruit and veggie juices or a shake, to make things less stressful. You still get most of the benefits of fasting, and well, you still get to look forward to some meals.
  • More complex fasts are ones like the Master Cleanse diet, which allows you to get some nutrients, though very few. With Master Cleanse, you're supposed to fast for a longer period of time than with a beginner fast, usually at least 10 days. These fasts require that you have a lot of self-knowledge. It's always recommended to begin with a shorter fast to see how it affects you.
  • Spiritual fasts are traditional and strict. They often mean going for long periods of time with no nutrients at all; you just drink water. Since their aim is more mental than fitness oriented, they're rarely—if ever—recommended by the fitness and nutrition industry.
How often you fast depends a lot on what type of fast you do. Longer fasts should not be done often, but 1-day fasts can be done regularly. An old common religious practice was to skip eating 1 day per week, which can be easily done without any associated fitness loss. So it's fairly easy to make fasting a regular part of your "diet."

To enter a fast, no matter which type it is, it's best if your diet is gradually lightened over a few days. First, heavy foods like meats and dairy products should be eliminated. Grains, nuts, and beans should then be reduced. The day before you begin, eat only easily digested foods like fruits, light salads, and soups. Likewise, you should break your fast gradually, going from lighter to heavier foods progressively. The diet after a fast should emphasize fresh, wholesome foods, which is easier because junk and convenience foods will usually make you feel awful. It's also vital that before, during, and after a fast you drink a lot of plain water. This keeps you hydrated and helps flush your system.

It's also important to note that fasting is not appropriate for everyone—especially pregnant and nursing women—and in some cases, it could be harmful. Those with health conditions should always have medical support during fasting.

Now that we've covered how not to eat, next we'll look into how we should eat, starting with the best food in the world.