Fasting and intermittent fasting (IF) has been getting a lot of attention for the past few years now. The interesting thing about fasting is that, it’s not a diet as many people refer to it as. It’s a pattern of eating.
There are several different variations of intermittent fasting, the most popular being the 16/8 in which you only eat in an 8 hour window. The 5:2 version is where you eat normally for 5 days and keep your calories extremely low for 2 days, keeping calories at 500-600. There are several other versions and if you would like to learn about each here is a nice summary https://www.healthline.com/nutrition/6-ways-to-do-intermittent-fasting.
For our purposes here I am going to use the 16/8 version as an example and discuss how it would work and what the pros and cons are.
I have done this for a few years and it has worked well for me but let’s talk about some of the benefits of fasting that science has uncovered:
- Intermittent fasting changes the function of cells, genes and hormones- The bottom line when you fast insulin levels drop and human growth hormone increases.
- Intermittent Fasting Can help you lose weight and belly fat: According to a 2014 review of the scientific literature, intermittent fasting can cause weight loss of 3-8% over 3-24 weeks (1). This is a huge amount.
The people also lost 4-7% of their waist circumference, which indicates that they lost lots of belly fat, the harmful fat in the abdominal cavity that causes disease.
One review study also showed that intermittent fasting caused less muscle loss than continuous calorie restriction (2).
- IF reduces insulin resistance, lowering your risk of type 2 diabetes.
- IF can reduce oxidative stress and inflammation in the body: Several studies show that intermittent fasting may enhance the body’s resistance to oxidative stress (3, 4).
- IF may be beneficial for heart health
- IF induces various cellular repair processes: When we fast, the cells in the body initiate a cellular “waste removal” process called autophagy (8, 9).
This involves the cells breaking down and metabolizing broken and dysfunctional proteins that build up inside cells over time.
- IF may help you live longer: Studies in rats have shown that intermittent fasting extends lifespan in a similar way as continuous calorie restriction (12, 13).
In some of these studies, the effects were quite dramatic. In one of them, rats that fasted every other day lived 83% longer than rats who weren’t fasted (14).
Although this is far from being proven in humans, intermittent fasting has become very popular among the anti-aging crowd.
AS you can see when you look at the above science based information it looks very promising but now let’s talk about the practical application and the pros and cons of that.
Speaking from experience, I have practiced the 16/8 method for a few years now and would say during that time I did that about 350 days out of 365.
In reading all of the benefits you might be saying, “Why wouldn’t I do this?”
Those were the benefits, there are some challenges. The most obvious one is waiting until 10-11 in the morning before you eat anything. The only thing you can have is water, black coffee or tea. Some people really struggle with this.
Another challenge is eating all of your calories in a short window. If you are trying to restrict calories this can be a benefit but for some they feel to full.
If you want to try IF and have trouble waiting that long to eat start slow. If you normally eat at 8, try and wait until 9. Work your way up to it.
Here is a quick list of benefits/pros:
- Less planning vs. eating 4-6 small meals per day
- Easier to consume less calories if weight loss is your goal
- All the possible health benefits listed above
- Takes the focus off of food
- Body composition benefits
- May cause severe hunger
- Eating a lot of calories in a short time period
- Concerns for those on medications
- Some people feel fatigued in the morning
- May cause low blood sugar in some
There are more pros and cons that you can find but it gives you a good starting point.
I would say that IF is not for:
- Folks with diabetes or other metabolic disorders
- People taking medications that require food
- Anyone with a history of disordered eating
- Women who are pregnant or trying to conceive
- Children and teenagers food
Intermittent fasting is not magic but simply a different way of eating with some possible health benefits that works very well for some people and not so much for others.
The only way to see if this is good for you is to try it. As I said earlier, you may need to ease into it but like anything I recommend, give it at least 30 days of being on it consistently before you make any judgments as to how it is working for you.