To fast is to go without food. We do this every time we go to sleep and then break our fast with the first food we eat that day (breakfast). Wikipedia defines Intermittant Fasting (IF) as an umbrella term for various diets that cycle between fasting and non-fasting during a defined period. Some folks take a day off food, and then a day on. Some choose to eat only during a restricted period of time during the day over the course of the fast (Time Restricted Feeding). How long you choose to fast is up to you and your metabolism. Some folks have unsteady blood sugar and would need to have a little something available, others don’t need anything and won’t feel hungry even after 2 days (me – I tried it. I was a little peckish at the end of day 2).
The question of “is it safe?” can be answered easily; YES. It is fine to take some time off eating. We carry hundreds of thousands of calories and store other nutrients in our bodies, so we don’t really need to eat everyday. Early on in our evolution we were not guaranteed daily food, it depended on foraging and hunting success. Food availability changed with the advent of agriculture and food storage. However, it’s a pretty wriggly can of worms involving habits, customs, culture, food addiction and lots of potentially conflicting information. As always, the answer is a qualified “It depends”, however research is supporting the use of Intermittent Fasting (IF) to maintain body health. There is something called a metabolic switch - after a certain time following the onset of fasting (12hrs) the body switches fuel sources and starts to metabolize “fat through fatty acid oxidation and fatty acid-derived ketones, which serve to preserve muscle mass and function. Thus, IF regimens that induce the metabolic switch have the potential to improve body composition…” . But this is not true in all bodies (of course) or for all time courses because everyone metabolizes at different rates. Many studies have show that IF has led to improved insulin and blood glucose levels, lower blood pressure, and sustained weight loss.
If you are going to try Intermittent Fasting (IF) start with simply pushing your breakfast time back and see how you feel. A recommended time frame is 16 : 8, or 16 fasting hours to 8 eating hours. It has been noticed that keeping the 8 eating hours during the daytime has improved outcomes (Circadian rhythm theory) because you are matching your fuel intake to your more active times.
Take away: Intermittent Fasting is an age-old protocol that is gaining more research support and recognition. Adding mindful fasting to nutritious diet choices and movement habits are some of the most sustainably healthy things you can do for yourself.
