What is Intermittent Fasting?

What is Intermittent Fasting?

In recent months, more light is being shined on an eating pattern known as Intermittent Fasting. Some famous
individuals like Terry Crews and Joe Rogan have come forth to personally testify to the effects of intermittent fasting. But just what is it?

Intermittent Fasting is a term used to describe many different methods of fasting. These include
those derived from religious context and of different durations/ratios of fasting and feeding. For example, Ramadan is considered a form of intermittent fasting, as is flip-flopping between fasting and feasting days.

What is the most common method? The most common method of intermittent fasting in the context of health, weight loss, and fitness is known as Time Restricted Feeding. As the name implies, this eating pattern is characterized by narrowing the window in which you eat to 8-10 hours per day. For example, if you find yourself finishing dinner at 7 pm, your first meal the following morning would be between 9:00 and 11:00 am (depending if you are adhering to the 8 or 10 hour window). It should be noted that one is not imposing a caloric deficit or skipping meals, but instead is eating the same amount of nutrients in  a shorter period of time during the day. Also, during the fasting period there are no restrictions on low calorie fluids (water, tea, etc.)  however, individuals with body composition goals are advised to reduce/eliminate liquid calories (soft drinks).

What are the benefits of adopting this eating pattern? There are numerous benefits associated with intermittent fasting and time restricted feeding. One of the most consistent findings after adopting this eating pattern is improvements in body composition (decrease fat mass). As fasting hours increase beyond 10-12 hours the human body will shift its metabolism from mainly carbohydrate metabolism to fat metabolism. In addition, one study looking at various Intermittent fasting methods on health and disease process found that normal weight and overweight individuals who adopted the time restricted feeding method (eating 8 hours per day or less) saw improvement in their body composition and improvements in markers of cardiovascular disease and metabolic
disorders 1 .

Another study looking into time restricted feeding and its effect on circadian rhythms and cardiometabolic disorders found that adhering to a total caloric intake in less than 12 hours per day prevents excessive body weight gain, improves sleep, and attenuates age- and diet-induced deterioration in cardiac performance 2 . A new pilot study looking into the effects of intermittent fasting on health markers of people with type 2 diabetes found those who met the fasting goal of 18-20 hours per day may improve key outcomes including body weight, fasting glucose and postprandial variability (after meal glucose level variability) 3 . As you can see there is mounting scientific evidence to support this eating pattern.

Key notes:
● Intermittent fasting is a catch term
● Time restricted feeding is narrowing the window in which you eat to 8-10 hours per day
● Benefits of this eating pattern:
○ Improve sleep
○ Improve body composition
○ Improve insulin resistance
○ Improve markers of CVD
○ Dietary intervention for T2D

[1] Impact of intermittent fasting on health and disease processes
[2] Time-restricted feeding for prevention and treatment of cardiometabolic disorders
[3] Effects of intermittent fasting on health markers in those with type 2 diabetes: A pilot study

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Anthony Barsby
Anthony Barsby
abarsby@deerfields.ca

As DeerFields’ Lifestyle Coach, Anthony uses the five pillars of lifestyle to provide clients with comprehensive and customized lifestyle coaching through face-to-face consultations and online mentoring. A Certified Exercise Physiologist, Anthony is proficient at fitness assessments and implementing exercise prescriptions catered to individual’s unique needs and capabilities.