As its name implies, intermittent fasting involves eating nothing for extended periods of time.
Fasting is a natural phenomenon for most animals, because food is not always readily available. In times of hardship, certain metabolic changes occur to allow the body to adapt.
As a result, humans evolved to be able to function without food for extended periods of time. In fact, fasting from time to time is more natural than always eating 3–4 (or more) meals per day.
Fasting is also often done for religious or spiritual reasons, including in Islam, Christianity, Judaism and Buddhism.
So how does fasting work?
The reason fasting is thought to be effective in weight loss is because it increases your body’s responsiveness to insulin. Insulin, a hormone that is released when you eat food, causes your liver, muscle and fat cells to store glucose. In a fasting state, blood glucose levels drop, which leads to a decrease in insulin production, signaling your body to start burning stored energy (carbohydrates). After 12 hours of fasting, your body runs out of stored energy and begins burning stored fat.
So the body only really exists in two states – the fed (insulin high) state and the fasted (insulin low) state. Either we are storing food energy (increasing stores), or we are burning stored energy (
How to fast?
There are several different ways of doing intermittent fasting — all of which involve splitting the day or week into eating and fasting periods. During the fasting periods, you eat either very little or nothing at all.
These are the most popular methods:
- The 16/8 method: Also called the Leangains protocol, it involves skipping breakfast and restricting your daily eating period to 8 hours, such as 1–9 p.m. Then you fast for 16 hours in between.
- Eat-Stop-Eat: This involves fasting for 24 hours, once or twice a week, for example by not eating from dinner one day until dinner the next day.
- The 5:2 diet: With this method, you consume only 500–600 calories on two non-consecutive days of the week, but eat normally the other 5 days.
Many studies have been done on intermittent fasting, in both animals and humans. These studies have shown that it can have powerful benefits for weight control and the health of your body and brain. It may even help you live longer.
Some handy tips to consider with fasting:
- Avoid sugars and refined grains. Instead, eat fruits, vegetables, beans, lentils, whole grains, lean proteins, and healthy fats (a sensible, plant-based, Mediterranean-style diet).
- Let your body burn fat between meals. Don’t snack. Be active throughout your day. Build muscle tone.
- Consider a simple form of intermittent fasting. Limit the hours of the day when you eat, and for best effect, make it earlier in the day (between 7 am to 3 pm, or even 10 am to 6 pm, but definitely not in the evening before bed).
- Avoid snacking or eating at nighttime, all the time.
Who should not fast?
- Underweight (BMI < 18.5) or have an eating disorder like anorexia.
- Pregnant – you need extra nutrients for your child.
- Breastfeeding – you need extra nutrients for your child.
- A child under 18 – you need extra nutrients to grow.
If you are interested in fasting for improved health benefits then we recommend reading the book “What the fast” by Caryn Zinn, Craig Rodger, and Grant Schofield or have a chat with your chiropractor in your next appointment.
Reference:
https://www.health.harvard.edu/blog/intermittent-fasting-surprising-update-2018062914156
https://www.healthline.com/nutrition/intermittent-fasting-guide#safety-and-side-effects
https://www.sciencedirect.com/science/article/pii/S1550413118302535
https://jamanetwork.com/journals/jamainternalmedicine/fullarticle/2623528