Here’s how to do intermittent fasting safely and sustainably

Lucky Kwong Chinese food

By Gabrielle Newman – The Fast 800

Science is evolving all the time, and it’s important to be aware of all the latest findings. It is also important to be discerning of these findings.

There have been news headlines in recent years suggesting that intermittent fasting, in particular 16:8 time restricted eating, doesn’t work (fasting for 16 hours and eating all required calories in 8 hours). But – after reviewing the science – the reality is rather more complex. 

For example, a study out of California, put a 16:8 time restricted eating plan to the test. Two groups of overweight and obese individuals were randomly allocated to a control group and an experiment group who was advised to consume all calories within an 8-hour window of time. The results – analysed across the 12-week period of the trial – suggested that there was very little difference between the two groups and in fact the experiment group seemed to have lost some muscle. However, the experimental group were given no advice around what to actually eat.

Intermittent fasting has health benefits

The Fast 800 recommends various forms intermittent fasting, not just for the weight loss potential but many health benefits.

Intermittent fasting has been shown to:

  • Burn fat – when you spend some time fasting, the glucose (primary energy) supply temporarily runs out, and your body has to switch to taking fat from your fat stores to burn as fuel.1
  • Reduce risk of Type 2 Diabetes – Excess fat impacts the function of the liver and pancreas, affecting your ability to produce insulin and keep your blood sugar balance in check. By fasting, you reduce your fat stores, improving liver and pancreas function.2
  • Help you live longer – Short term fasting activates a process within the body called ‘autophagy’ whereby dead, diseased or worn-out cells are broken down and gobbled up (autophagy means ‘self -eat’) to make way for the shiny new cells that keep us young.3
  • Improve your cardiovascular health – Studies show intermittent fasting can reduce blood pressure and make your body more efficient at clearing fat from the bloodstream after a fatty meal, thus reducing your risk of heart disease.4
  • Improve sleep – fasting causes levels of the sleep-promoting hormone, melatonin, to rise, which can help you fall asleep faster and stay asleep longer.5
  • Bolster immunity – fasting provides the opportunity for the body to repair cells and deal with inflammation. IF also encourages the breakdown of white blood cells and triggers stem cell-based regeneration of new immune system cells.6

We also advocate time restricted eating (TRE), acknowledging that longer periods of fasting are not necessarily more beneficial and, for most people, trying to stick to 16:8 long term will be challenging.

16:8 time restricted eating is not for everyone

Instead, we encourage people to begin by eating within a 12-hour period (12:12). For some, this is challenging enough and some health benefits have been seen in this form of TRE. Once you are comfortable with that, if you’d like, move to 14:10. The advice from the experts is, once you have reached the weight you want to be, move back to 12:12. Like the Mediterranean Style Diet, eating to a 12:12 pattern can form a permanent part of a healthy lifestyle.

What you consume in your eating window is just as important

The type of calories you consume throughout your eating window are just as important as maintaining a fasting period; preserving your muscle mass through adequate protein consumption is a key part of The Fast 800.

Creating calorie-controlled meal plans to help you thrive through your journey and to enable your fasting takes a lot of planning and experience. I formulate the meal plans to be balanced for variety, nutrition, calories, protein and deliciousness! The Fast 800 programme is based on the latest science to support long-term health – it is designed for you to ebb and flow with different dietary approaches that support your changing health and life circumstances.

Intermittent fasting is not suitable for everyone, particularly those who are under 18, pregnant or breastfeeding or are on medication. Seek advice from your GP before commencing any diet or fitness regime.


  1. Human trials of TRE at the University of Surrey found eating breakfast 90 minutes later than usual, and dinner 90 minutes earlier each day led to a drop in body fat and falls in blood sugar levels and cholesterol.
  2. A major study published in 2018 by Professor Roy Taylor of Newcastle University and Professor Mike Lean of Glasgow University, showed that nearly half of those people who followed an 800 calorie rapid weight loss diet not only lost a lot of weight, but by doing so were able to put their diabetes into remission and come off medication.
  3. VALTER LONGO studies show short term fasting activates a process within the body called ‘autophagy’ Longo, Valter D., and Satchidananda Panda. “Fasting, circadian rhythms, and time-restricted feeding in healthy lifespan.” Cell metabolism 23, no. 6 (2016): 1048-1059.
  4. Intermittent Fasting in Cardiovascular Disorders—An Overview
  5. The effect of intermittent fasting during Ramadan on sleep, sleepiness, cognitive function, and circadian rhythm
  6. Prolonged Fasting reduces IGF-1/PKA to promote hematopoietic stem cell-based regeneration and reverse immunosuppression

ABOUT Gabrielle Newman – BHSc (Nutritional Medicine)

Gabrielle Newman is a Clinical Nutritionist, BHSc (Nutritional Medicine), with a special interest in weight management, hormonal and metabolic health. She has a love of food that stemmed from her previous career as a short order cook, as well as a Permaculture Design Certificate.

Gabrielle is the Nutritionist and Recipe Developer for The Fast 800. She has a passion for making good health attainable and sustainable through educating people to make the right health choices for them.

Gabrielle Newman