Empty plate.
August 21, 2019 | by Jasmine Miller MS, CN

One of the most popular dieting tools today is fasting. Though many people view fasting in a negative light, there are several reasons why fasting can be a great tool in maintaining good health and a healthy weight. Here are the facts about fasting and a few reasons why it may be something to consider trying.

Fasting Benefits

Fasting, in the purest sense, is abstaining from consuming any food or beverages for a certain period of time. This, however, does not include water, unsweetened tea, and coffee. Today, fasting is used for weight loss, cleansing, and regulation of blood sugar levels. When done correctly, fasting can also improve blood pressure and increase brain-derived neurotrophic factor (BDNF) which is a protein that plays an important role in memory and learning.

Types of Fasting

Generally, the most popular methods of fasting last between 12 hours to 72 hours. One method that is particularly popular is the “16:8 method” where you consume meals during an eight-hour period and then use the other 16 hours of the day to fast. For more prolonged periods of fasting, 24 hours, 48 hours, 72 hours, or even longer, this will largely depend on your current health status. Anyone who wants to fast longer than 24 hours should consult with a medical provider first and would need to ensure proper electrolyte consumption during that time frame. Frequency of fasting will depend on your current health status and whether or not you decide to add it into your routine indefinitely. Many physicians recommend fasting 1-2 times per week.

How Fasting Works

The point of fasting is to let the body have a period of time to take a break and “refresh” the system. This gives your body a break from the energy demands of digesting and absorbing food. Some individuals may also achieve a state of ketosis. Ketosis can occur when there is no longer glucose (sugar) available as an energy source. As a result, your body breaks down fatty acids and produces ketones that your body can use for energy. You can achieve ketosis either by fasting or significantly reducing your carbohydrate intake. This limits the availability of carbohydrates and sugars for energy. Many of our cells prefer glucose when it is available, but when it’s not available those cells can and will use ketones for energy.

Fasting and Athleticism

For the average person who is regularly active by doing aerobic exercise like walking, jogging, swimming, or biking for 30 to 60 minutes per day, fasting should not impact performance at all. It may actually help improve fatty acid oxidation (the use of fat for fuel) when exercising in a fasted state (i.e. first thing in the morning before eating any breakfast). For someone who is engaging in much more strenuous and/or prolonged physical activity, fasting can still be beneficial for improving fatty acid oxidation but it becomes more complicated in terms of when and how frequently fasted training sessions should be done. For those who are fairly inactive, fasting can be a helpful tool in maintaining bodyweight.

Fasting and Caloric Intake

The idea that our body will “eat” muscle in times of fasting is inaccurate. Protein and muscle are “expensive” fuel sources to rely on and your body would much rather use its stored fat for energy. People who use the 16:8 fasting method often reduce the number of daily meals they consume. It is important to note that if you are eating only one or two meals per day it is important to make sure the food you eat contains adequate nutrients and is not just “whatever you feel like.” You want to make sure you are choosing nutrient-dense foods. If you are only eating one meal a day that meal should include several servings of vegetables, at least six to eight ounces of protein, and some form of natural fat like olive oil, avocado, or nuts.

It is important to keep in mind that fasting may not be a great option for everyone. If you are considering fasting, check with your physician to ensure it is the right decision for your body.

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