Intermittent Fasting 101

What is intermittent fasting (IF)?

Intermittent fasting (IF), also known as time-restricted-eating, is an eating pattern that cycles between periods of fasting and eating. While most diets focus on what to eat, intermittent fasting aims to control when you eat.

Fasting for a certain number of hours each day exhausts the body’s sugar stores and starts burning fat. This is known as metabolic switching.

There are several different types of fasting schedules that generate positive results, but the most common is the 16/8 method. This involves restricting your daily eating period to 8 hours, and fasting for 16 hours in between (most of which is overnight). As an example, you could start your first meal at 11am and finish eating dinner by 7pm.

A minimum fasting window of twelve hours per day will allow improved blood sugar regulation and reduce the exposure to gut-associated toxins. A longer fasting period might be required to enter ketosis (14-18 hours) or trigger autophagy (16-24 hours).

What happens to our bodies during intermittent fasting, and what are the corresponding health benefits associated with these changes?

Cellular Repair: In a fasted state, your cells initiate important cellular repair processes, namely autophagy, which is known to:

• Remove defective cells that are attributed to neurodegenerative diseases and cancer.
• Provide energy and building blocks for cells that could still benefit from repair and prompts regeneration of healthy cells, which promotes anti-aging. Studies have shown that fasted rats lived 36–83% longer.
• Positively alter the expression and regulation of genes related to longevity and protection against disease.

Anti-Inflammation: Some studies show IF reduces markers of inflammation, which is a key driver of many chronic conditions.

Heart health: IF may reduce “bad” LDL cholesterol and blood triglycerides, a type of fat that occurs when you eat more calories than your body needs.

Brain health: IF increases the brain hormone BDNF and may support the growth of new nerve cells. It may also protect against Alzheimer’s disease.

Weight Loss: After hours without food, the body exhausts its sugar stores and starts burning fat.

• In order for your body to access these fat stores, Human Growth Hormone (HGH) increases (as much as 5-fold), which supports fat loss and muscle gain.
• IF can also reduce insulin resistance, lowering blood sugar by 3–6% and fasting insulin levels by 20–31%. This is thought to help protect against type 2 diabetes and minimize risk of cancer.

Does overeating during non-fasting windows negate the benefits of intermittent fasting?

If the feeding times are packed with high-calorie and high-sugar foods, you are less likely to see the health benefits. It makes it harder for your body to turn on its metabolic switch, so when your sugar levels fall, you can experience hunger cravings that will affect your ability to avoid eating and experience the benefits of intermittent fasting.

How does intermittent fasting impact hormone production and regulation?

Fasting can play a direct role in balancing hormones; when you fast, insulin levels go down and fat cells can release the stored sugar from the body. High amounts of sugar in the body can throw hormones off balance, so fasting is a great tool to manage insulin levels. When the body is in balance with circadian rhythm (we eat mostly when it's light and fast when it’s dark), proper functioning of hormone production is enabled.

Would everyone benefit from some form of intermittent fasting?  

Mostly everyone (exceptions below) would benefit from some form of intermittent fasting. It’s easy to incorporate intermittent fasting into your wellness routine by making a conscious effort to eat your last meal earlier in the day and not right before bedtime, as well as to make better snacking choices. Once these conscious efforts become routine, your body will be guided by intuition.

Who in particular should be wary of intermittent fasting?

General rule of thumb: Make sure to consult your primary care physician before trying intermittent fasting.

• People with advanced diabetes or who are on medications for diabetes
• People with a history of eating disorders
• People who take medications for blood pressure or heart disease and may be more prone to electrolyte abnormalities from fasting
• Women who are trying to get pregnant, are pregnant or are breastfeeding