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  • Danielle Stephens

Myth Busting: The Sirtfood Diet

Updated: Jan 14



I’m sure a lot of you have come across the Sirtfood Diet in the last few weeks…the diet that Adele a allegedly followed to lose 7 stone. The headline for this diet is ‘lose 7lbs in 7 days’ and is endorsed by various media outlets and celebrities that claim, ‘you can still eat chocolate and lose weight’.


So, what is the Sirtfood Diet? Is it really the new healthy lifestyle choice that we should all be following? Or is just another fad diet?

What is the sirtfood diet?

The diet focuses on including specific foods that contain high amounts of compounds known as polyphenols. They are found in relatively high concentrations in various plant foods. There is evidence to suggest that a few specific polyphenols can increase our metabolism and induce various health benefits, including increased cognitive functioning and anti-ageing effects. This is due to their activation of genes called sirtuin genes; these have been aptly named the ‘skinny genes’.


The founders of this diet identified foods that have high concentrations of these specific polyphenols and named them ‘sirtfoods’. Examples of sirtfoods include:

  • Green tea

  • Dark chocolate (85%)

  • Apples

  • Citrus fruits

  • Turmeric

  • Kale

  • Buckwheat

  • Blueberries

  • Capers

  • Parsley

  • Red wine


There are two phases to this diet. Phase one involves the consumption of only 1,000 kcal per day for the first 3 days, in the form 3 ‘sirtfood green juices’ and one ‘sirtfood rich’ meal per day. Phase two comprises of the remaining 4 days; calorie intake is increased to 1,500 kcal per day and consists of consuming 2 ‘sirtfood green juices’ and 2 ‘sirtfood rich-meals’ a day.


These two phases are usually followed for 2 weeks, followed by a ‘maintenance phase’. Dieters are encouraged to find what works best for them, consuming high amounts of these so called sirtfoods in sirtfood rich meals.



What this diet claims to do...

The headlines behind this diet are rapid weight loss (7lbs in 1 weeks!!), increased energy and alertness, better sleep and protection against chronic diseases (heart disease, cardiovascular disease).


But are these claims true? Is there robust scientific evidence suggesting the beneficial effects of the consumption of these foods? And therefore, should we all start adopting this diet?


First, let’s dive into some simple science behind the diet.

First up, what are polyphenols and why all the hype?

There has been much interest and research undertaken on polyphenols in the past few years because of their potential health benefits. Polyphenols are found in various plant food sources and are involved in various important functions in our bodies, including the regulation of metabolism.


Scientific studies have shown that they have antioxidant and anti-inflammatory properties that may have preventative effects against various chronic diseases such as obesity, type 2 diabetes and cardiovascular disease.


Resveratrol is the polyphenol that has been identified as the specific sirtuin gene activator. This polyphenol has been shown in petri dish experiments, and in animal experiments to activate our sirtuin genes and exert the beneficial effects outlined above.

Clinical evidence for the use of resveratrol and its health effects

Unfortunately, there is no strong clinical evidence from human intervention trials that this sirtuin activator found in the so called sirtfoods, actually has any anti-ageing effects or directly increases our metabolism.


Another factor to consider when looking at the scientific evidence behind this diet, is the dose of polyphenols used in the clinical trials. The participants are often given high doses of polyphenols which cannot be obtained from the diet, therefore for you and me the results may not be relevant.

Is this yet another fad diet?

To put it simply, yes. Yet again we come across a diet that hooks us in with claims of rapid weight loss and improved brain function and energy levels. However, these effects are most probably not down to the inclusion of these specific foods.


The rapid weight loss seen in the first week will be mostly water weight. This diet is inherently low in carbohydrates. Carbohydrates are stored in the muscles and the liver as glycogen. Your body breaks down glycogen into glucose to be used as a fuel for energy. Glycogen is stored alongside water in our tissues, so when glycogen is lost, so is water. Consequently, the 7lbs that an individual apparently loses is in fact mostly just water.


The first phase of the diet restricts you to only consuming 1,000 kcal, that is more than half the recommended daily intake of calories! To sustain this for 3 days will be extremely hard.


Additionally, the diet says to consume 3 green juices. The Public Health England Guidelines recommend only consuming 1 juice drink/smoothie per day due to the high amounts of free sugars.


Weight loss takes time. It’s not something that can occur overnight. Achieving a sustained healthy weight can be done through following a nutritious well-balanced diet – when I mean balanced, I do also mean including something sweet (yes, chocolate is good for the soul!!). This coupled with regular exercise (walking, running, dancing) is the best way to lead a healthy lifestyle.

Inclusion or exclusion diet?

The founders of this diet claim that this is not a fad diet, it’s a lifestyle, and say the diet does not focus on excluding foods but focuses on including foods in our diet. However, I disagree.


This diet focuses on specific food groups and consuming specific foods that are high in the sirtuin activators. This therefore cuts out many other nutritious foods from our diet which also have many beneficial health effects.


This diet is very low in carbohydrate which can have health consequences. This also means that the diet is low in dietary fibre – a nutrient that is extremely important for gut health. Therefore, following this diet on a long-term basis may have more detrimental than beneficial health effects.


How can we follow a healthy lifestyle without the need of another fad diet?

Despite the claims that the sirtfood diet is a long-term lifestyle, there has been no scientific evidence suggesting that individuals adhere to the diet and its long-term health benefits.


The founders of the diet claim that it was evidence from the beneficial effects of the Mediterranean diet that sparked their interest in sirtfoods.

There have been ample observational and randomised control trials that have looked at the health benefits of this Mediterranean dietary pattern on many disease outcomes.


Following a Mediterranean diet has been shown to decrease the risk of cardiovascular disease, cancer, obesity, type 2 diabetes and neurodegenerative diseases such as dementia.


This is a dietary pattern, not a ‘diet’. Dietary patterns look at our whole diet and our lifestyle; it does not focus on specific foods or food groups, including or excluding them.


The Mediterranean diet focuses on including a range of food groups such as:

  • Plenty of fruit and vegetables

  • Nuts and legumes

  • Oily fish that contain high amounts of mega 3

  • Wholegrains high in dietary fibre

  • Unsaturated oils – specifically olive oil

So why not adopt a Mediterranean style diet? It is a dietary pattern more inclusive that does not state that we should only drink green juices and have specific foods.


The Mediterranean diet has been through rigorous scientific trials with strong evidence suggesting that it has long term beneficial health outcomes.

Let the evidence do the talking.

P.S. we should be following a lifestyle that makes us feel great about ourselves. We shouldn’t feel the need to be ‘skinny’ or lose weight for other people. This diet is marketed as a way to ‘look better’. This angers me!! Please remember that your body shape and size do NOT define who you are!!

Let's all EAT HAPPY and LIVE WELL.


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