Intermittent Fasting For Weight Management & Health
Every single week there seems to be some brand new diet on the health scene that promises the world. In the end, it delivers very little. When a way of eating really sticks around, we start to take notice.
Enter intermittent fasting.
What is intermittent fasting?
To put it simply, intermittent fasting describes small periods of eating that are broken up by longer periods of not eating (AKA fasting).
When looking at this concept, it is important to take a step back and realize that we all fast during the night while we sleep. Overnight we abstain from food. We break our fast with whatever we choose to eat the following morning.
So, the term ‘intermittent fasting’ covers a range of eating patterns – some of which involve much longer fasts than others. As a result, there are several different approaches to intermittent fasting that you can choose to use.
Some intermittent fasting protocols suggest that you simply extend your overnight fast by a few hours. Others recommend you abstain from eating for days at a time.
For the sake of simplicity, in this article, we are going to be talking about the most common form of intermittent fasting. It is also known as time-restricted feeding. This intermittent fasting is the type that revolves around simply extending your overnight fast.
How to do intermittent fasting?
When using this time-restricted feeding approach to intermittent fasting, some people recommend adhering to regimented and timed fasting protocols.
In this scenario, you would allocate yourself an eating window that remains the same every single day, and limit your daily food intake to that window – for example, some people will only eat between 1pm and 9pam every single day.
In this manner, they will obviously avoid food outside of these times to ensure a longer period of fasting is maintained each and every day.
Now, although this approach does seem logical, it won’t suit everybody.
This is because these somewhat arbitrary and regimented eating windows don’t factor in the individual variances in the time people wake up or go to bed. As such, a single eating window will not suit every individual circumstance.
You see, the benefits of intermittent fasting ultimately come from spending time in a fasted state. This means that a fasting period that lasts from anywhere between 14 and 18 hours will work effectively no matter what time that fast starts.
This means that to implement intermittent fasting daily, you can simply choose to break your fast (by eating your first meal) around 6 hours after waking every single day.
This will work no matter what time you wake up, irrespective of whether that happens to be 5am, 9am, or even 11am.
One thing to remember is that during your eating window, it isn’t like you can eat whatever you want. Intermittent fasting isn’t a magic bullet, but a way to improve your health and your eating habits.
So, your intent should be to eat regular healthy meals during your eating period – just like you would under normal circumstances.
Related Article: The Ketogenic Diet: How It Affects Athletic Performance
What are the benefits of intermittent fasting?
Intermittent fasting has made waves within the health industry of late due to its implications for both health and weight loss. As a result, I have tried to cover off some of the key benefits you can expect to see when it comes to intermittent fasting.
Intermittent Fasting & Weight Management
When it comes to how intermittent fasting can help weight management, it comes down to the effects it exhibits on the hormonal system.
Firstly, after a prolonged fasting period, your insulin secretion declines rapidly (Heilbronn, 2005).
Insulin is what we would commonly consider an ‘energy storage hormone’, because it helps shuttle proteins, carbohydrates, and fats, into the body’s cells, where they can then be used at a later date.
When your insulin is high, your body is in an ‘energy storage’ state. Alternatively, when your insulin is low, your body will have easier access to fats for energy.
Now, the second big hormonal change that you see with a prolonged period of fasting is a significant increase in your secretion of human growth hormone (Ho, 1988).
As human growth hormone is involved in both the breakdown of fat for energy and the growth of muscle tissue, it stands to reason that fasting can have further favorable effects on your body composition – namely by reducing fat and increasing muscle growth (Blackman, 2002).
To summarise, intermittent fasting ultimately places your boy in a state where it is easier to lose weight, thus making weight management easier (Byrne, 2018).
With all this in mind, there is a bit of a caveat here – we know that weight management is still ultimately determined by your total caloric intake.
So pretty simple, if you still eat more energy than you burn (even while intermittent fasting) you will still gain weight.
Intermittent fasting, therefore, provides a way to facilitate the process of eating less and expending more energy on a physiological level, which sets the foundation for successful weight management.
How does intermittent fasting affect health?
In conjunction with their impact on weight management, the hormonal changes mentioned above can also have some pretty positive implications for health.
We have already mentioned that intermittent fasting the above protocol can lower your insulin levels – but what I failed to mention is you will also see a general increase in insulin sensitivity, as well as a chronic reduction in resting blood glucose levels (Arnason, 2017).
Both of which are key markers of metabolic health.
These often come with associated reductions in blood pressure and marked improvement in blood cholesterol, typified by increases in HDL cholesterol, and subsequent reduction in LDL cholesterol (Moro, 2016; Sutton, 2018).
As a result, intermittent fasting in this way appears to cause a huge improvement in both cardiovascular and metabolic health, reducing your risk of developing heart disease and diabetes considerably.
Pretty damn impressive if you ask me.
Who is intermittent fasting good for?
If we were to look at the above information, it would be hard to see any negatives associated with intermittent fasting. However, like all other diets, this isn’t necessarily the case.
Intermittent fasting appears to be a great fit for those who are looking to lose weight and maintain health. It also may offer another potential tool for people with cardiovascular disease and diabetes to improve their life without medication.
But, given that intermittent fasting does limit the amount of food you can physically consume in a day by providing a shorter eating window, it may not be optimal for athletic performance or those looking to build muscle mass.
As such, if you are in either of these circumstances, you may want to strictly use intermittent fasting on your rest days, and stick to normal eating patterns to increase energy intake on heavy training days and during competition.
This is a good way to maximize health without dropping your performance.
Related Article: FODMAPS and Exercise
Male vs Female Intermittent Fasting
There is also some evidence to suggest that the sharp calorie restriction that can result from intermittent fasting may lead to a disruption of the menstrual cycle (De Souza, 2004).
While uncommon, this is still something that needs to be considered.
In this scenario, it may be best for females to start with a 12-14 hour fasting window initially. This is to test the waters (so to speak). This should still be enough time to cause some positive hormonal changes. This time works without running the risk of a severe and chronic energy deficit.
What happens when you stop intermittent fasting?
There is currently no real research on what happens after you stop doing intermittent fasting after a prolonged period of time. However, there is anecdotal evidence that would suggest that you will have no issue.
The weight that you lose while intermittent fasting should stay off and the improvements in health should also be retained.
But (there is always a but…), this is very much built on the assumption that you do not overeat once you return to your normal eating habits.
As a result, I would be inclined to think of intermittent fasting as a semi-consistent lifestyle change – a way of eating that you revert to for most of the time.
Are there any long-term effects of intermittent fasting on metabolism?
Similarly, there is currently no evidence to suggest that you will see any long-term effects on your metabolism after a chronic bout of intermittent fasting.
It is always important to remember that your metabolism is most heavily dictated by the amount of muscle mass you carry on your body. It is also determined by your activity levels. Therefore, assuming you maintain those two factors throughout the duration of your intermittent fasting period, you should see no change in your metabolism at all.
How does exercise play a role in intermittent fasting?
I really wanted to finish this article by giving a little bit of information around how you can manage exercise while undertaking intermittent fasting.
In the perfect circumstance, you would exercise somewhere in between your first and second meal. This would approximately be early or late afternoon.
This would guarantee that you have enough energy available to manage your exercise session. Additionally, it would provide you with everything you need to recover from that training session.
But I understand that life doesn’t always allow for this sort of thing, which leads into our next point perfectly…
Can I exercise fasted?
In short – yes.
In my opinion, it is a bit of a misconception that you must have a pre-workout meal. You see, if you choose fasted training, your body will still be full of all the energy you consumed the previous day.
Subsequently, neither your performance nor your recovery will be all that limited.
This will hold true for a normal 45-60 minute training session. However, it’s probably not a good idea to perform a really long duration event in a fasted state. It will impair both performance and recovery.
Be smart about it and use your head.
Take Home Message
It really does appear that intermittent fasting deserves the hype it has received from the health and fitness community. This interesting way of eating can seriously help improve weight management while causing substantial improvements in cardiovascular and metabolic health.
So, what are you waiting for? Give it a go and get back to us – we would love to hear from you.
Heilbronn, Leonie K., et al. “Alternate-day fasting in nonobese subjects: effects on body weight, body composition, and energy metabolism.”. The American journal of clinical nutrition 81.1 (2005): 69-73.
Ho, Klan Y., et al. “Fasting enhances growth hormone secretion and amplifies the complex rhythms of growth hormone secretion in man.”. The Journal of clinical investigation 81.4 (1988): 968-975.
Blackman, Marc R., et al. “Growth hormone and sex steroid administration in healthy aged women and men: a randomized controlled trial.” Jama 288.18 (2002): 2282-2292.
Byrne, Nuala M., et al. “Intermittent energy restriction improves weight loss efficiency in obese men: the MATADOR study.” International journal of obesity 42.2 (2018): 129.
Arnason, Terra G., Matthew W. Bowen, and Kerry D. Mansell. “Effects of intermittent fasting on health markers in those with type 2 diabetes. A pilot study.” World journal of diabetes 8.4 (2017): 154.
Sutton, Elizabeth F., et al. “Early time-restricted feeding improves insulin sensitivity, blood pressure. Oxidative stress even without weight loss in men with prediabetes.” Cell metabolism 27.6 (2018): 1212-1221.
Moro, Tatiana, et al. “Effects of eight weeks of time-restricted feeding (16/8) on basal metabolism, maximal strength, body composition, inflammation. And cardiovascular risk factors in resistance-trained males.”. Journal of translational medicine 14.1 (2016): 290.
De Souza, Mary Jane, et al. “Fasting ghrelin levels in physically active women: relationship with menstrual disturbances and metabolic hormones.” The Journal of Clinical Endocrinology & Metabolism 89.7 (2004): 3536-3542.
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