Is Intermittent Fasting Safe?

Intermittent fasting is a dietary approach that involves cycling between periods of fasting and eating. It has gained popularity for potential health benefits, such as weight loss and cellular repair.

Common intermittent diet regimes include 5:2 or 16:8

But does it stand up to the hype?


Intermittent fasting and cell renewal

The research on intermittent fasting is still evolving but as it stands a lot of the claims that are made around improving longevity are not substantiated by the evidence.  These claims evolve from a process in the body called autophagy; the removal of damaged cells, proteins and pathogens. 

People have oversimplified this process to conclude that more removal of these cells = better, but as with most things more does not always equal more! 

Autophagy happens anyway despite fasting and will probably be more influenced by other activities such as exercise than it will by fasting and in in some tissue types increased autophagy would be a sign of a diseased state.  There is some emerging research in animal models that there could be a link to fasting and increased longevity, but this doesn’t translate into the human research as yet, and of course we are not the same as mice, so although with further research this may change as it stands, I can’t make any specific claims that Intermittent fasting will increase your lifespan.

Intermittent Fasting for Weight Loss

Intermittent fasting can be one tool to help people to manage their weight.  It is successful for some, but for many it is unsustainable.  The research does not show intermittent fasting to be more beneficial or superior to any other calorie deficit diet and therefore if you are going to struggle to maintain not eating for long periods of time, feel tired, hungry, deprived or lacking in energy because of this eating plan then there is no reason to put yourself through it!

Is Intermittent Fasting Safe?

It can be safe, but it needs careful planning, and it is not for everyone.  If you have a medical condition or take certain medications it is always best to check with your Doctor before starting a regime like this.

Some of the regimes suggest extended periods without food, sometimes a whole day or more and this can certainly be risky to your physical and mental wellbeing.  I would not recommend these extended fasts to anyone. 

For those of you who struggle with your relationship with food, comfort or emotionally eat, binge eat, have a history of an eating disorder or struggle with your body image I wouldn’t recommend this diet for you.  By being restrictive with your food in such a strict and inflexible way can often lead to disordered eating behaviours and impact on your mental wellbeing. 

Many are not aware that their relationship with food is suffering, common signs are feelings of anxiety when you eat certain foods, labelling food as good or bad, feelings of guilt or shame after eating foods, removing foods from your diet; these are just some of the signs that you may have a poor relationship with food and restrictive diets are likely to risk causing you harm.

If we do not get enough of the nutrients our bodies need then we can impact on our health and wellbeing and this is something to consider when intermittent fasting, if you skip a meal, can you still get all your nutrition into your day?  Most of us do not get enough fibre, which is vital for gut health and reduces risk of diseases such as type 2 diabetes and cardiovascular disease, many women do not get enough iron and calcium- is this going to be further reduced by this way of eating?  Earlier we were talking about fasting for longevity, but being malnourished is certainly not going to contribute to increase life expectancy and so there is always a bigger picture to consider.

Should I intermittent fast?

Remember we are all different and just because intermittent fasting is working for someone you know, doesn’t mean it will be right for you- you need to find a way of eating that fits in with your lifestyle, values and goals- not someone else’s.

This is why I encourage my clients to follow a more intuitive approach to eating where they are focussing on health rather than weight as this often leads them to eating in a way that is both enjoyable and health promoting. 

If you decide to try intermittent fasting, it’s important to approach it safely and responsibly. Start with shorter fasting periods and gradually increase the duration over time. It’s also crucial to maintain a balanced diet and ensure you are getting all the necessary nutrients during your eating windows.  Listen to your body and monitor how you feel during fast periods and make adjustments as needed.

In summary, I personally think from the evidence we have to date on intermittent fasting there is no need to be rushing out to do follow this diet regime.  We already naturally fast overnight and I think focussing on what you can add into your diet to make it balanced and nutritious is a healthier approach to restriction and rules, but of course do what works for you based on your goals and lifestyle.

Disclaimer.  This is general information and is not meant to be individual advice.  If you are struggling with your nutrition or relationship with food and want further support with this then please ask for professional help from a Dietitian or a Registered AfN Nutritionist.