Fasting, Intermittent Fasting, Time Restricted Feeding

Dr. Paulina Gasiorowska, MDFasting, Featured

July 5, 2017  /  Fasting, Featured
avocado and proteins

By Dr. Paulina Gasiorowska,


Why has ‘not eating’ has become so popular?

Over the last couple of decades, researchers have looked into the benefits of fasting. I wouldn’t call it a dietary fad, as it has been around forever.

Humans have engaged in fasting out of necessity (no food!) and later, for spiritual reasons for centuries. Many physicians in the past have recommended fasting during times of illness as a way to combat disease. Recently, the practice of fasting has resurfaced. Here is a brief overview of types of fasts and their health benefits.

Types of Fasts

1) Time restricted feeding

Having a 6-8 hour eating window in a single day.

The levels of our hunger hormone (ghrelin) are the lowest upon waking, so it is recommended to take advantage of this by lengthening our overnight fast.

For example, if we consume our last meal at 8pm and we wake up at 8am (12 hours of fasting), it is recommended to extend that fasting period by 4-6 hours and eat our first meal at noon or 2pm. This ensures we are consuming food in a 6-8 hour window.

2) Alternate Day Fasting

Consuming 0-300 calories on non-eating days, followed by a full diet the next.

3) Prolonged fasts (1+ days)

Some researchers recommend an occasional 24-72 hour fast, perhaps monthly or every season.

During all forms of fasting, it is VERY important to hydrate. Water, flavoured with mint leaves or cucumber slices or lemon, and herbal teas are all great choices. For fasts longer than 24 hours, it is recommended to also consume salt. Drinking home made vegetable or bone broths with sea salt is a great source of electrolytes. Lastly, epsom salt baths at night are a great way to take in magnesium, since ingesting magnesium on an empty stomach can cause stomach upset.

Health Benefits of Fasting

1) Metabolic health

During a fast, insulin levels (the hormone that tells our body NOT to use fat as energy) are kept very low. This has been shown to lead to weight loss, (even if same number of calories are consumed), with the loss of body fat and sparing of lean body mass.

Human studies also show a decrease in insulin resistance, improvements in HbA1c, improvements in diabetic kidney disease, fasting insulin, and cholesterol levels.

2) Brain protection

During a prolonged fast, we start to produce ketones. This state is often referred to as “nutritional ketosis”. This can also be accomplished with strict carbohydrate restriction, but getting there with fasting is quite a bit simpler.

Circulating ketones have been shown to protect our neurons from damage as well as decrease inflammation. Early research shows improvements in neurodegenerative diseases, such as Alzheimers and Parkinson’s disease.

3) Autophagy

During a fast, when both insulin and amino acids (from protein) are kept low, our body engages in autophagy. This is a process by which our cells sense a low level of nutrition, and they start disassembling and removing damaged parts of the cell. This is a form of cellular detoxification. Researchers believe that it is this very effect, in combination with circulating ketones that protects us from neurodegenerative diseases. Autophagy may also protect us from various forms of cancer.

As you can see, the health benefits are quite impressive. Engaging in an abstinence from food may seem daunting at first, but for many it is much easier than they had anticipated.

Whether one chooses a one day or a 16 hour fast, what is consistent among all of these methods is a decreased number of meals consumed. Perhaps the recommendation of 5-6 small meals a day was never a valid one?

Maybe asking our bodies to secrete insulin and process food ALL day long is not good?

For now, at the very least, sticking to our old way of 3 meals a day is likely a good idea. For more on the topic, ask one of our physicians at Balance Medical Center.

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Dr. Paulina Gasiorowska, MD

Dr. Paulina Gasiorowska has been a practising physician for 6 years. She completed her medical school education atUBC and her residency training in both Family Medicine and Emergency Medicine at McGill University. Since completing her training, she has worked in numerous Emergency Departments in Quebec, Ontario, British Columbia, as well as Bermuda allowing her to see a wide array of patient populations and pathologies.

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