Intermittent fasting is the latest trend in health circles and a growing body of research seems to indicate that this eating pattern may help with weight loss and add years to your life.
Abstaining from food or water for a certain period of time is not new concept and has been practiced for centuries. Fasting has been practiced for cultural or religious rituals, for greater clarity of mind, and or for healing purposes. In the last couple of years there has been an unsurpassed interest in intermittent fasting and time-restricted eating due to a small body of research, which suggests that controlled fasting may produce a multitude of health benefits such as: weight loss, improved insulin sensitivity, better mental focus, improved sleep and increased autophagy, a form of cellular cleansing.[1,2,3,4,5,6]
Many of the traditional forms of fasting involved abstinence from food for days on end. The health benefits were noted, however the practice entailed discipline and was not always comfortable. New methods as seen in the 5:2 intermittent fasting method, and the 18:6 and 14:10 time-restricted eating methods are easier to follow and not as uncomfortable. Some participants have reported a period of adjustment including hunger pangs and headaches at first, but after a few weeks have sailed through with no adverse effects.
Fasting is the greatest remedy- the physician within
Intermittent fasting or Time-Restricted Eating- Which method is better?
Fasting is not for everybody! Expecting or nursing mothers, children, teenagers or people with severe health conditions should refrain. If you are unsure make sure you have a chat to your GP to get the all clear. Most of the research is based on the 5:2 intermittent fasting method or the 18:6 Time-restricted Eating method. A recent study (Wilkinson et al. 2020) with a 10-hour eating period and 14 hour fasting period also produced favourable results for weight loss, restful sleep and some cardiometabolic improvements.  It should be noted that the participants in the study had metabolic syndrome and results should not be compared against the general healthy population. Metabolic Syndrome is a cluster of risk factors that may predispose a person to cardiovascular or kidney disease and diabetes. Some of the risk factors (three are necessary for diagnosis) are elevated waist circumference, high triglycerides, blood pressure, blood glucose levels or reduced HDL-C. 
Most of the studies for intermittent and time-restricted eating methods have shown positive health outcomes. It is really a matter of what suits your lifestyle and what you are most comfortable with.
5:2 Method involves eating regularly for 5 days and eating very little for two. This means the energy intake is 2000-2500 kilojoules on two of the days. It is important to optimise the nutritional quality of what you eat on the 5:2 intermittent fasting method. Foods to include are plenty of vegetables, fruit, lean protein and whole grains.
The other two methods involve eating solid food and beverages in either 6- or 10-hour windows with 18 or 14 hours of fasting. Drinking lots of water is encouraged in the feeding and fasting windows as this helps to remove toxins from the body. The window of eating is up to the individual and should suit your lifestyle requirements. For example, an office worker who follows an 18:6 pattern of eating will have their first meal at work at 1pm and finish with the last meal at home at 7pm each day for the duration of the program.
Top Tips for Fasting for Beginners
Avoid highly processed foods and focus on vegetables, fruit, legumes, lean proteins and whole grains.
Stop snacking and drinking liquids (soda, coffee, juices, smoothies) other than water between meals.
Burn extra fat by building muscle tone such as resistance training.
Start with a form of fasting that works for you and your lifestyle.
Drink plenty of water and carry a glass or metal container with you at all times.
Include protein (plant-based or meat) with every meal.
Ultimately, whilst much remains to be learned about Intermittent Fasting and Time-restricted Eating, the positive outcomes from the research to date cannot be ignored in an increasing obesity pandemic. It is hoped that long-term efficacy and future research is warranted in larger human studies with attention in long term efficacy.
Unfortunately, the 5:2 intermittent fasting method, 18:6 and the 14:10 methods are open to personal interpretation and susceptibility to misinformation. A qualified nutritionist can work out your kilojoules requirement for weight management and recommend a tailored and balanced food plan that meets your body’s nutrient needs for energy, muscle growth and recovery, skin health and wellbeing.
1 Anton SD, Lee SA, Donahue WT, McLaren C, Manini T, Leeuwenburgh C, et al. The effects of time restricted feeding on overweight, older adults: A pilot study. Nutrients [internet]. 2019 Jul 1 [cited 2020 Feb 8];11(7):1-9. Available from: https://www.ncbi.nlm.nih.gov/pubmed/31262054
2 Antoni R, Johnston K, Collins A, Robertson MD. The Effects of Intermittent Energy Restriction on Indices of Cardiometabolic Health. Res Endocrinol [Internet]. 2014 Jun 28 [cited 2020 Jan 28];1–24. Available from: http://www.ibimapublishing.com/journals/ENDO/2014/459119/459119.html
3 Mattson MP, Longo VD, Harvie M. Impact of intermittent fasting on health and disease processes., Ageing Research Reviews [internet]. 2017 [cited 2020 Feb 20]; 39:46–58. Available from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5411330/pdf/nihms831290.pdf
4 Rynders CA, Thomas EA, Zaman A, Pan Z, Catenacci VA, Melanson EL. Effectiveness of intermittent fasting and time-restricted feeding compared to continuous energy restriction for weight loss. Nutrients [internet]. 2019 [cited 2020 Feb 10]; 11(10). Available from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6836017/
5 Sutton EF, Beyl R, Early KS, Cefalu WT, Ravussin E, Peterson CM. Early Time-Restricted Feeding Improves Insulin Sensitivity, Blood Pressure, and Oxidative Stress Even without Weight Loss in Men with Prediabetes. Cell Metab [Internet]. 2018 [cited 2020 Feb 10]. 27 (6):1212-1221. Available from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5990470/
6 Mark Mattson. Why fasting bolsters brain power ; 2014 [cited 2020 Feb 10] TEDx John Hopkins University. Available from: https://www.youtube.com/watch?v=4UkZAwKoCP8
7 Wilkinson MJ, Manoogian ENC, Zadourian A, Lo H, Fakhouri S, Shoghi A, et al. Ten-Hour Time-Restricted Eating Reduces Weight, Blood Pressure, and Atherogenic Lipids in Patients with Metabolic Syndrome. Cell Metab [internet]. 2019 [cited 2020 March 2]; 31(1); 92-104. Available at: https://www.sciencedirect.com/science/article/pii/S1550413119306114
8 Australian Family Physician. Australia. RACGP 2016. The Metabolic Syndrome 2013. [cited 2020 March1]. Available from: https://www.racgp.org.au/afp/2013/august/the-metabolic-syndrome/