Intermittent fasting is becoming a rapid trend to help shed unwanted kilos, improve metabolic health, and an anti-ageing and longevity intervention. This article explores the benefits of intermittent fasting and its effect on lifespan, ageing and metabolic disease.
A recent opinion article published by the University of Sydney suggests that the health benefits of intermittent fasting is not as beneficial to our overall health and longevity as it was once thought.
The same article was also published in the Sydney Morning Herald on January 4th, 2023. Both opinion articles stated that whilst intermittent fasting showed modest weight loss in obese patients, it did not reduce inflammation, improve glucose tolerance or insulin sensitivity after six months in obese patients who did the 5:2 fasting model.
This particular 5:2 fasting model allowed participants to have their usual Western diet for five days and only ate non starchy vegetables of two days. This is vastly different to other 5:2 fasting models where participants were encouraged to adopt a healthy eating plan.
What bias do we see?
The results from the study published by the Sydney Morning Herald and University of Sydney did not compare the outcome of this particular fasting model to traditional fasting models. This is frustrating because most people would consider these to be reputable sources of information.
What people do not understand is, there are different models of intermittent fasting. The fasting models which proved to have the most benefit to health and lifespan are:
- Fasting for 12-16hrs and have a eight hour feeding window,
- Fasting for two non-consecutive days and healthy eating on the other five days,
- Periodic fasting lasting 2-7 days and repeated once a month.
It is also important to note that while these fasting models did not have calorie restrictions, participants are encouraged to adopt a healthy diet. Studies show those who experienced the most benefits were participants who adopted a mediterranean diet or plant based diet, or a diet that contained less animal protein.
The Dangers of Intermittent Fasting
We should also note there are limitations to intermittent fasting, when it is taken to the extreme, especially when protein intake falls below 5% of your total daily calorie intake. This can induce muscle wasting. Vitamin and mineral deficiencies are other important considerations.
New studies are also looking at the long term implications of intermittent fasting - e.g. across four generations. We will update on this topic later.
Are we supportive of intermittent fasting?
Absolutely. When done properly, intermittent fasting have shown to produce many health benefits by inducing cell autophagy, weight loss and improve metabolic health in those with diabetes. It is a cost effective and non invasive method anyone can implement into their daily life.
In a world where we have increasing obesity and metabolic diseases, we believe everyone should have access to non-biased information, especially when it is cost-effective and non-invasive.
Although intermittent fasting requires a lot of self discipline, breaking your fasting cycle once in a while does not bring you back to baseline.
Anyone considering intermittent fasting should consult their health professional if they are unsure. The purpose of this article is to share the advantages associated with intermittent fasting based on scientific evidence, and what people need to be aware of. We do not recommend fasting during pregnancy.
Helen Huynh B Pharm MPS
- Belman, O (2019). 'Eat less, live longer? The Science of fasting and longevity.' University of Southern California Leonard Davis. [Access]
- Longo, V et al. 'Intermittent and Periodic Fasting, Longevity and Disease.' J Nature and Ageing. 14 January 2021. [Access]
- Berry, S (2023). 'Intermittent fasting may not be all that it's cracked up to be, study finds.; Sydney Morning Herald. Published January 4, 2023. [Access]
- Unknown (2023). 'Intermittent fasting leads to weight loss, not improved health.' University of Sydney. Published January 10, 2023. [Access]