Fasting - that is, refraining from eating food, for set periods of time, a practice that has been observed for thousands of years, and is an important tradition in many religions and cultures across the world.
In the Neolithic Period/Stone age time, the people would eat between Dawn till Dusk, for example today (8th January 2023) Sunrise was 08.13 and Sunset was 16.06, which is less than 8hours of daylight.
Today there are lots of twists on this ancient practice as trends among dieters, health-seekers change, when advocates claim its benefits i.e. long-term weight loss, improved health and even anti-aging effects.
So what does 16:8 mean - it translates into 16hours of fasting - not eating or drinking except water for that period of time each day and eating for 8hours of the day.
16:8 is also known as 16:8 Intermittent Fasting - which you can repeat the cycle as frequently as you'd like i.e. just once or twice per week to everyday, its completely up to you and how you feel when actively observing this practice. (You can give yourself some flexibility when Fasting if you need it, by doing what's known as 'Dirty Fasting', which is where you can eat /drink up to 100kCal in your actual Fasting period.)
The benefits of fasting 16:8 are in the scientific early stages of research, and currently the 'Zoe Project' are working with Kings College London, Stanford Medicine, Harvard T.H. Chan School of Public Health and Massachusetts General Hospital, conducting 'The Big IF (Intermittent Fasting) Study'. Today (8th January 2023) is day 76 of reporting of 148,532 contributors.
The early results before this current study report Intermittent Fasting supports weight loss, improves blood sugars, reduces cholesterol and increase longevity.
We all actively practice Intermittent Fasting, as none of us eat when we are sleeping but our fasting windows are all different and unless we have studied Intermittent Fasting would not recognise what we were actively doing.
Why should we not eat for a 16hour window, because someone who eats regularly throughout their waking hours is constantly topping up their livers source of Glycogen, a stored form of Glucose energy gained from Carbohydrates. When we stop eating, the body depletes the Glycogen quite quickly. Those Glycogen stores can get used up in about 10hours if you are Fasting - more quickly if you add in a workout. Once Glycogen stores are used up the body starts searching for alternative sources of energy. Its at that point, the body starts beginning to break down stored Fats into substances called Ketones to get the job done. This metabolic switch does so much more than meets the bodies energy needs, the switch from using Glucose to Ketones is a triggering point - it shifts your metabolism from focusing on storage and growth to being all about repair and replace.
How can you start actively practicing Intermittent Fasting. Start by identifying your current Eating and Fasting windows.
Then question why are you eating at those times i.e. Routine, Hungry, Social...
Decide on a new eating window that fits you.
i.e.
9am - 5pm
10am - 6pm
11am - 7pm
12pm - 8pm
1pm - 9pm
You don't need to start with the 16:8 Fasting window, it might be you chose 10:14.
i.e.
8am - 6pm
9am - 7pm
10am - 8pm
11am - 9pm
and gradually work your way up to 16:8, if this is something you wish to practice.
Resources:
Book: The Complete Guide to Fasting: Heal your body through intermittent, alternate-day, and extended Fasting. Author Jason Fung, MD and Jimmy Moore.