Quick Facts on 3 Types of Fasting


By: Joy Stephenson-Laws, Founder


Fasting has become a widely popular diet trend. If you do it right, many believe it is the answer to losing weight. But there is more to fasting.  There is a vast body of scientific research that says fasting may promote longevity, reduce your risk of developing cancer, cause cellular repair and detoxification, boost brain function, improve blood sugar and cholesterol levels and more.

But before you jump on the fasting bandwagon, it is always good to speak with a competent healthcare professional to see if fasting is a viable option for you. You also have to consider your lifestyle and be honest with yourself about whether you are just looking for a “quick fix” for weight loss. Remember, there really are no quick fixes when it comes to sustainable weight loss. Fasting takes patience, diligence, discipline and really educating yourself about what your body needs. 

There are many types of  fasting. We’ve previously blogged about intermittent fasting, which is basically when you don’t eat for a certain period of time during the day (sometimes as long as 16 hours).  To help you get started on your fasting journey, let’s discuss three methods that you may be interested in..

The three methods, time-restricted feeding, intermittent calorie restriction and periodic fasting, are extensively discussed in this report. For each method of fasting described, very credible doctors stand behind the method he or she believes in. And each of the doctors came to the conclusion to support a certain method through his or her own research. These doctors are basically fasting experts.

Here are the three methods:

  • Time-restricted feeding.

This is a type of fasting in which you restrict your calorie intake on a daily basis for a certain period of time, usually eight to 12 hours. The doctor referenced in the report is an advocate of this type of fasting and suggests that this method is beneficial for our circadian rhythms. It is also known as the 24-hour sleep/wake cycle. Some refer to circadian rhythms as the body’s clock. Circadian rhythms may influence hormone release, eating habits and digestion, body temperature and other important bodily functions (including wound healing).

But according to the doctor, we have more than one circadian clock. For example, he says we have a clock in the gut, a clock in the kidney and one in the liver that “make up the whole of our biological rhythm.” Each of these clocks is turned on and off at certain times. And the concept is that when these clocks are all in sync, our body’s overall system works best.

Those people who do not fast never really turn their digestive systems off.

According to the doctor, time-restricted feeding gives your digestive system a break and time to repair itself. Think of it this way: your digestive system is turned on when you first consume calories during the day. And every time you eat, your digestive system is being turned on. Most people eat throughout the day, never really giving their digestive system a chance to turn off and repair itself. And apparently, a seven to eight hour window of not eating while you are sleeping is not enough.

The doctor conducted a study with mice and found that those who followed time-restricted feeding performed better at fitness tests and also were better protected against obesity and other metabolic diseases as well as inflammation.

If you and your doctor decide this is a good fasting option for you, you may want to start fasting eight to nine hours during the day and then working your way up to 10-12.

  • Calorie restriction

This type of fasting entails reducing the amount of calories you consume in a day, to around 800 to 1,000 calories. It is less time-focused oriented than the method discussed above. It is also called the 5:2 diet or 2-day diet, because you restrict your calorie intake for two consecutive days out of the week and then the other five you eat “normally.” This does not mean you get to eat processed, junk foods on the off days. Or that you can eat an 800 calorie candy bar and nothing else on the diet days. This fasting method stresses always maintaining a nutrient-dense diet with whole foods, such as fruits and vegetables.

On the restricted calorie days, it is recommended to avoid carbohydrates and focus on eating protein (which may help you feel full with such a low calorie intake).

The doctor who is an advocate of this method is a breast cancer researcher, who focuses on breast cancer and weight loss. Through her studies she has found that weight loss can reduce the risk of breast cancer.

She believes calorie restriction is better than total fasting (zero calorie consumption), because, in her opinion, it is more practical and does not cause you to lose lean body mass. She also said that total fasting can cause big fluctuations in your body’s fatty acids and can lead to insulin resistance. Furthermore, you can continue to workout with calorie restriction fasting, which is very attractive for people who do not want to consider fasting if it is going to deter them from working out.

I know for me, this type of fasting seems more appealing because I don’t like to go a day without some physical activity - even if it is hiking with my dogs.

But on the flip side, the doctor advocating for this type of fasting does not recommend this diet for healthy people. There is limited evidence to support that people who are not sick or do not have metabolic issues should do this type of fasting. But, again, speak with your doctor and get a second opinion to be extra diligent. Being proactive about your health is educating yourself to the fullest and finding answers.

  • Periodic fasting

This type of fasting is pretty intense. In a nutshell, “Periodic fasting requires limiting calories for between three and five days, such that cells deplete glycogen stores (glucose from food stored as energy) and begin ketogenesis (breaking down fatty acids for energy).”

You can also achieve ketogenesis by not eating anything at all, but this could lead to malnourishment and other health issues. The doctor advocating for this type of fasting created a five-day diet program in which your caloric intake is limited to between 770 and 1,100 calories per day. 

“This helps with the mental and physical rigors of fasting by providing nutrients to the body without stopping the fasting process at the cellular level.”

The doctor’s concept is that you destroy when you starve, and you rebuild when you feed. You are not starving to a dangerous level, but the idea is that you deplete your body’s glycogen (a storage form of glucose) stores and then begin feeding off of the body’s fat stores. He does not believe in the 5:2 diet (method discussed above), because he says this does not allow the body’s cell to enter a fasting state.

Through his studies of humans adopting this fasting practice, he found that people experienced improvement in body weight, waist circumference and BMI, absolute total body and trunk fat and risk factors for aging and disease such as systolic blood pressure (which measures the pressure in your blood vessels when your heart beats).

The doctor also found even greater results in animals who practiced periodic fasting. They showed extended longevity, lower visceral fat (the dangerous belly fat), reduced cancer incidence, improved immune system, better cognitive function and more.

So as you can see, there are different methods to the madness! But again, speak with a competent healthcare specialist before you attempt to fast. And you always want to be proactive by taking routine nutrient tests. These tests will identify whether you have any nutrient deficiencies or imbalances. If you do, a competent healthcare professional can work with you on making the necessary dietary changes and possibly recommend quality supplements you can take.

Enjoy your healthy life!

The pH professional health care team includes recognized experts from a variety of health care and related disciplines, including physicians, attorneys, nutritionists, nurses and certified fitness instructors. This team also includes the members of the pH Medical Advisory Board, which constantly monitors all pH programs, products and services. To learn more about the pH Medical Advisory Board, click here. 




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