Intermittent Fasting - The Pros, Cons and Doing It Safely!

Most of us have heard the term ‘fasting’ getting thrown around over the last few years. There seems to be two camps - those that love it or those that feel completely overwhelmed by it. I’m a bit of both. It works beautifully for some people and not so well for others. Let me help you understand the pros and cons of intermittent fasting and how you can do it safely.

Fasting isn’t a new health strategy. Humans have always fasted - it’s how we were metabolically designed to eat and live. We used to feast then have famine periods.

When we talk about intermittent fasting most people think of a time-restricted eating window, so you fast for a number of hours each day and eat your meals within specific hours each day. There’s also 24 or 48 hour fasts; but let’s focus on intermittent fasting for a second.

There’s a number of different fasting techniques now (some I’m all for and others I’m not)

Recent data shows 42% of adults are currently trying to lose weight, while another 23% are fighting to maintain their weight. For this reason, fasting has taken off, as people turn to it to help with weight loss and weight management.

Here’s a few of the most popular fasting techniques:

• 5:2 diet

This is when you eat ‘normally’ for five days of the week, while the other two restrict calories to 500–600 per day (which is a quarter of your daily calorie requirement)

• 16:8 approach

This is when you fast for 16 hours and eat meals within an 8 hour window. For example, if you finish dinner at 8pm you’ll fast until midday the following day.

• Alternate Day Fasting

This is when you fast one day and eat the following day; often referred to as ‘fast and feast’. People tend to do this for one, two, three or four days a week

The research on fasting &

the pros and cons:

Let me be clear - there is only a handful of human studies for fasting (there’s a number of studies on mice/rats but those results don’t necessarily translate to humans.)

What we see in the studies with rodents is that females and male rodents respond very different to fasting and the fasting technique.

Males can thrive with more extreme fasting measures (like alternate day fasting), whereas for females long fasting periods this can drive hormonal imbalances, including stress and sleep disturbances.

Research shows that for most people, having a gentle intermittent fasting window (of 12-14 hours every 24 hours) can be beneficial in terms of giving the digestive system a break, lowering insulin and supporting healthy weight management/fat loss.

For example, if you finish dinner at 7pm then you fast overnight until 7am. Ofcourse, you can drink water in the fasting window - but no food, as every time you eat it causes your digestive system ‘on’, and your body has to release insulin in response to the change in blood sugar.

Pros of intermittent fasting:

• Improve insulin sensitivity, weight loss/weight management and metabolic health

• A number of patients will experience improvements in clarity, focus and energy

• During periods of famine our bodies are forced to use fat as fuel (rather than food)

• We can develop a connection with our hunger cues and appetite. This seems to have been lost overtime, as there’s now an abundance of food, and usually it’s cheap and nasty food that’s full of crap!

Cons of intermittent fasting:

• It takes into account the TIME your eating meals but it doesn’t consider WHAT you’re eating.

• People can consume too few calories - this can drive deficiencies, hormone imbalances, bowel irregularities including constipation, mood swings, fatigue etc.

• Lack of nutrients - it can be hard to consume all the nutrients you need in a day when you’re only eating 2 meals. I often see people lack with their 5-6 serves (= 5-6 cups!) of vegetables when they’re eating within a 6 or 8 hour window, right?!

• It doesn’t suit everyone, including those with a history of eating issues/disorders, those with hormonal imbalances/fertility issues, underweight people, low blood pressure, etc. You should check with your practitioner before starting ANY new eating pattern or diet.

My approach to fasting:

Most people tend to eat for 14-15 hours every 24 hours, which we know is proven to be linked with insulin resistance, weight gain (especially around the middle) and metabolic disease.

So, I often talk to patients about two key starting points: focus on meals over snacks, and practice a gentle fasting window.

• Meals over snacks

  We’ve never had a more overweight, obese or insulin resistant population; over 64% of Aussies are now overweight/obese. We tend to overeat. Every time we eat our body releases insulin, so one of the best ways to get control and balance insulin levels is to stop grazing and eat meals! Aim to eat 3 nourishing and nutrient-dense meals a day.

• Your digestive system has an inbuilt cleaning crew, the MMC (migrating motor complex), and their job is to move undigested food through the small intestine and move any excess bacteria through. However, the MMC is activated after 3 hours of fasting; this is another reason to have small fasting pockets in your day, as enabling your MMC to be activated supports digestion, absorption and your whole gut microbiome. Read more about your MMC here

• Gentle Fasting Approach - 12:12

  Most of us benefit from starting with a gentle fasting approach; fast for 12 hours and eat your meals within a 12 hour window.

  • This is doable when you consider that if you finish dinner by 7.30pm you fast overnight and don’t eat brekkie until 7.30am the following day.

    • Water, herbal tea and black coffee are absolutely OK during the fasting window

For some patients, when they’re on a weight loss journey we may practice a longer fasting window, such as a 14-hour fasting approach. However, this is individual and is closely monitored to ensure it suits them and meets their needs.

Keep in mind, fasting isn’t for everybody, especially children and teenagers, pregnant and lactating women, highly stressed men/women, those with low blood pressure and other specific conditions.

Always check with your doctor or health practitioner if fasting or the type of fasting that would be best for you.

If you’re after some nutrient-dense meals/snacks to consume while slowly switching to a more meal-based lifestyle with a gentle restricted feeding time, check out my latest wholefood recipe eBook here

If you’ve enjoyed this, you’ll love catching my free training on fasting - here