Leading Personal Trainers: 477-479 Glen Huntly Road, Elsternwick

Why Intermittent Fasting Can Be Bad For You

IF (Intermittent Fasting) can be bad for you if you’re not very good at handling stress or if you have a high stress load. I’ve personally had success applying IF in my early training days when my goal was weight loss. When I started training I was 100kg and through IF and shitty exercise routines (I wasn’t as educated back then) I still managed to lose 10-15kg’s, so yeah it works to a point.

When it can be bad for you?

You’re not good at handling stress: IF requires long periods of fasting 8,10,16+ hours before eating your first meal and if during that period of fasting you’re causing intermittent releases in your stress hormone cortisol that’s going to impact your gut microbiome and gut lining. A change in your gut microbiome can affect your mood and nutrition decision making through the gut to brain axis and an increase in inflammation can lead to leaky gut.

You have a high stress load: Similar to not being good at handling stress having an already high stress load through work, over-training, not getting enough sleep, relationship drama etc IF only adds to that stress load especially if it’s your first time experimenting with IF. This is something you have to be aware about because perceived mental stress produces the same hormonal reaction and causes as physical stress.

Turning the bad into good.

The good thing is that your body is adaptable and It’s going to adapt to stress by learning how to deal with it better as long as you’ve taken the time to recover and learn from what went wrong. For e.g. your first day doing an 8 hour fast is going to be harder than your 4th or 5th day of fasting. You’ll consciously exert less stressful efforts during your fasting phase. You’ll get into less arguments at work, get less irate at your colleague making a mess in the lunch room and overall you’ll let things that aren’t worth stressing over slide a lot more.

If you know you have a high stress load than focusing on your overall health is more key than any nutritional fad. Managing your blood sugar with more regular meals, getting in quality nutrition and making sure you’re getting in a good balance of strenuous exercise plus rest is going to be better for your goals especially if it’s fat loss and weight loss. If you really want to do IF you can apply it in a less stressful way by doing once or twice per week instead of everyday.

IF final thoughts:

IF will always work better for someone if they’ve got more to lose. It’s going to be more effective if you have 15+kg’s to lose compared to if you have the last 5kg’s because of a see-saw affect. When you’ve got more to lose a release of cortisol and adrenaline throughout the day promotes more energy burning which helps weight loss. When you’ve got less to lose a release of those same hormones only helps you to a point; more becomes detrimental because it negatively impacts your recovery affecting your ability to efficiently release cortisol and adrenaline next time.

IF can be great as a nutrition method lifestyle tool if you’re already where you want to be with your body composition and training goals. You can execute IF once or a couple days a week as a convenience and maintenance tool. It’s good to give your gut a break every now and then if you’re consistently fuelling it with protein, carbs and fats to support training (usually requires more nutrition). You can also afford to have an IF day if you’re travelling or having a really busy day at work because it’s not going to have that much of an impact to your body composition or training performance, it’s more for convenience for that day.

If you’ve been doing or done IF before with success and it no longer works it’s because your physical and nutritional needs are different to what they were before. When someone loses a bunch of weight through training they usually become more outgoing, do more activities, socialise more, meet more people and train more. It’s natural that their body requires more protein, carbs and fats to fuel this new lifestyle and to also increase their training performance which will have even more positive effects to their body composition.


Experience a more efficient and individualised way of training to achieve your fitness goal. Meet Gordon, discuss your goals and be taken through an individualised PT session in our studio.

Book in below:

We will only send you awesome stuff


This privacy policy sets out Dr. Nicole Beukens uses and protects any information that you give us when you use this website.
Dr. Nicole Beurkens is committed to ensuring that your privacy is protected. Should we ask you to provide certain information by which you can be identified when using this website, then you can be assured that it will only be used in accordance with this privacy statement.
Dr. Nicole Beurkens may change this policy from time to time by updating this page. You should check this page from time to time to ensure that you are happy with any changes.


We only ever collect the information that we need in order to serve you.
Generally, this just means collecting your first name and email address that you enter, for example, when you request a resource, register for a webinar, or submit a message via a contact form.
if you are a paying customer, we also collect your billing information including your last name and your postal address.