When you don't eat for a while, several things happen in your body. The main benefits are found when the body initiates important cellular repair processes and changes hormone levels to make stored body fat more accessible during a time when no calories are consumed.
Here is a quick look at some of the beneficial changes that occur in your body during fasting:
- Insulin levels: Blood levels of insulin drop significantly, which promotes insulin sensitivity whilst also facilitating fat burning.
- Human Growth Hormone: During fasts, blood GH levels may increase as much as 5-fold. Growth Hormone has been touted as the ‘anti-aging hormone’ and higher levels of this hormone can facilitate significant fat burning and muscle gain.
- Cellular repair: The body induces important cellular repair processes, such as removing waste material from cells, repairing damaged DNA, binding free radicals with anti oxidants via NRF-2 gene activation and removing dead or damaged Mitochondria.
- Gene expression: There are beneficial changes in several genes and molecules related to longevity and protection against disease.
So what's the bottom Line?
Many of the benefits of intermittent fasting are related to these changes in hormones, gene expression and function of cells.
When you fast, insulin levels drop and human growth hormone increases. Your cells also initiate important cellular repair processes and change which genes they express. To simplify further, your body heals, grows and burns fat!
Now that we have established how fantastic fasting is for our health in general, the remainder of this article will focus on several fasting models that have been popularised in media in recent times.
For each fasting model, we will analyse the most popular methods, see if the benefits stack up, and give recommendations on how to implement these into a healthy lifestyle for the average Joe.
Here are 3 of the most popular ways to implement a fasting protocol:
1. The 5/2 Diet
This is a popular introduction to the fasting world for a number of reasons, but primarily because it does not involve fully fledged fasting. It is essentially a structured approach to calorie restriction.
The basics of this dietary style are on two, non-consecutive days of the week you will eat approximately 25% of your daily caloric needs.
For the average male, this will work out to be around 500-600 calories, and for the average female, it will be approximately 350-400 calories.
The arrangement of the days is not important, as long as they are not consecutive.
It’s that simple! Eat normal 5 days per week and restrict calories on the other two days.
Now in terms of benefits, calorie restriction is the only proven way to lengthen one’s lifespan and is indeed a powerful tool in your health arsenal. In studies on mice, it was found that chronic calorie restriction increased lifespan by 10-20%!
Extrapolate that to the human example and that could be the difference between living to 80 or 100!
Although the relative percentage may not be the same, you get what I'm saying.
Seeing as the foundation of this 5/2 diet is essentially just structured calorie restriction, and there is a host of solid science backing restriction as the only real method of lengthening our lives, it is safe to say that whilst it isn’t technically a fasting based diet, it does stack up well!
Furthermore, it is relatively easy to stick to and it will benefit your health.
At the very least, this diet will generate a calorie deficit of approximately 3000 calories per week in men or 2200 in women per week, which is nearly half a kilogram of weight loss worth of calories you are no longer consuming every week!
To this end, I give the 5/2 diet a big tick of approval for the average Joe looking to live longer, be healthier and generally watch the waist line!
2. The 16/8 Intermittent Fast (IF)
Popularised by such celebrities as Terry Crews, the 16/8 IF approach is perhaps the most flexible, adaptable and actual fasting based diet strategy to implement.
Essentially, you fast for 16 hours of the day and restrict food into an 8-hour window. This may look something like having an ‘eating window’ from 10am to 6pm (8 hours) and then not eating again once you finish at 6pm until the next morning at 10am.
For many, this is a VERY convenient fasting structure to adopt into their lifestyle.
Most people can withhold breakfast until 10am and most can have dinner by 6pm, allowing 16 hours for their body to fast between 6pm and 10am where they are repairing, building and burning.
Our take home on the 16/8 IF model is that it gives all benefits of fasting, can be adopted and maintained easily, and is still plenty of time spent feasting when applied to 7 days per week. It is also worthy of note that 10-6 were just exemplary schedules, you can customise this 16/8 split into whatever best suits your daily routine.
Shift workers, for example, may rotate this window, whilst 9-5 workers will find great ease implementing the fasting window to literally just their working hours, 9am to 5pm.
It is entirely up to you how you wish to utilise the eating window and regardless of how you do, you will reap the health benefits!
3. 24-hour Fasts
Definitely the least popular of all the fasting methods, the 24 hour straight fast has fantastic health benefits.
However, there is one major drawback... There are VERY few people with the willpower to not eat for 24 hours straight on a regular basis! This is not to discredit the method, however!
On the contrary, it is the most puritan of all the methods and will have the most pronounced health benefits of all 3 approaches to fasting discussed here.
For example, provided you eat normally on the days not fasting, the average male with a 2000 calorie daily requirement will lose approximately 300 grams, or 1/3rd of a kilogram per week just from one day of fasting per week!
One day of sacrifice, for significant weight loss, cell repair and hormonal optimising benefits!
Over a month this is 1.2kg that will be primarily from pure body fat due to the nature of the hormonal response to fasting. Pretty cool stuff!
To finalise, fasting has a host of health benefits that anyone from any walk of life could benefit from.
Therefore the question should not be ‘if’ you employ IF, but rather, under what model you will implement it to make it a sustainable change to your diet.
Whether it’s the super flexible 16/8, the hard line 24 hour fast or the calorie restricting 5/2 diet, all will benefit your health immensely.
It is all about finding which one suits your lifestyle so that you can stick with it for the long-term in order to really see some pronounced benefits!