Writing about diets is something I’ve tried to stray away from when writing a fitness section: the suggestion that radical shifts away from simply eating well are worth our time, or not feeding into male body image issues, is hard to justify. But sometimes a diet is getting so much attention, and something new appears as a part of it, and so it feels like a great chance to take a look at one of the dieting terms we’ve never really discussed here at GQ.
The Sirtfood Diet was originally launched in 2016 by Aidan Goggins and Glen Matten. Those who follow it eat a diet of foods rich in “sirtuin”, which they say protect the cells in the body from dying when they are under stress. These foods are, fundamentally, a very healthy list, with some great antioxidant additions that can make the diet very appealing: 85 per cent dark chocolate; coffee and red wine are there alongside a lot of more conventional whole foods. The diet has been followed by celebrities including, reportedly, Adele, David Haye and Conor McGregor.
In terms of calories, the original Sirtfood Diet has a week-long initial phase in which calories are reduced to 1,000 per day for three days, consisting of one sirtuin-rich meal and several green juices. This is then extended to 1,500 calories (two juices and two meals) by the end of the week. There is then a second phase, known as “the maintenance phase”, which lasts two weeks, which begins to look at a longer life plan of eating three balanced sirtfood-rich meals with one green juice a day.
The latest variant on the Sirtfood Diet is now available at KX, an exclusive gym in South Kensington. It is here that the Sirtfood Diet was first created, and now it is offering the “Vital Diet” – a week-long crash course that focuses on NRF2s rather than sirtuins. When NRF2 is activated, the Vital Diet proposes, “something truly remarkable happens: a loud wakeup call is delivered to a vast number of genes, which then go on to produce hundreds of different enzymes and compounds that protect and revitalise our cells – including the body’s most powerful antioxidant, anti-inflammatory and detox chemicals”. Each day consists of two meals that are rich in ingredients they say increase NRF2 production. Plus, every day, those following the diet consume a smoothie, a turmeric shot, a “watercress wonder juice” and a couple of chocolate cherry bites for when the sweet tooth hits. Each day comes to a total of 1,500 calories.
With the recent renaissance in the sirtfood approach, I had to wonder: what were the benefits for men (and women) in such a brief, specific diet? Is there any benefit in changing how you eat for seven days, can this much of a calorie deficit be sustainable if you train intensely, and will any results I see in that week be the sign of more long-term change?
First, the diet itself: I turned up to KX on a Monday morning and did two blood tests: a Free Oxygen Radical Test and a Free Oxygen Radical Defence examination. I then did a full-body composition scan and was handed my first day’s worth of food (each day’s food was couriered to me). The menu handed to me for the week really sets the Vital Diet apart from other meal plans you may have done as part of a fitness regimen: there’s shakshuka, a grilled fillet of beef, chicken with miso and truffle, and a steak tartare. Everything that arrived was delicious, well-seasoned and a joy to eat, even if the amount of bottles and containers you’re left after each day is a bit daunting (they are, however, compostable and recyclable).
The first day went relatively fine. But by the second day, I began to notice something odd. I’d been told this diet and calorie intake was appropriate for someone doing regular exercise, but by my Tuesday workout I found even the warm-up to be a struggle: I had never known what it was to feel leaden before this, but I could barely move. Wednesday’s workout, too, suffered and afterwards I couldn’t cope with just the calories on offer and had to supplement with some carbs just to get through the day.
A diet plan like this is never easy: it makes it harder to see people because your diet is very strict, drinking is off the table and you do find yourself sitting and waiting for the next intake. But it’s also hard when, at the tail end of a pandemic, your mental health begins to go off a cliff. There were a few days when I was completely destroyed mentally, and not having anything substantial, enjoyable or comforting to eat was a hard pill to swallow. But then again, this is really my own circumstances and not the diet’s: I don’t think that what I was eating had any effect on whether I was up or down.
During the week, friends thought I was looking healthy. At the end, when I got my results, I’d lost a kilo in weight and three inches round my waist in a week. I had expected this to be a brief trial of something that is offered longer-term for clients, but discovered all Vital Diets are just a week, before proposing other nutrition plans for clients at KX. But so brief a diet seemed, to me, suspect: how could one week of living differently have any effect on my long-term health? Plus, while the results are brilliant, I also had to wonder: was this not just the immediate shock of your body changing how it fuels itself? Would this be sustained?
I reached out to a few nutritionists we’ve worked with before at GQ and generally the responses were all the same: the Sirtfood or Vital Diets are not doing anybody any harm and are diets full of delicious and healthy whole foods. But that doesn’t mean that it’s a sustainable way to change the way I eat, nor does it mean that the results of the first week would stay the same for a long time to come.
Mike Molloy, the owner of M2 Performance Nutrition and who has a PhD in molecular biology, said that while sirtuins absolutely do have a role in modulating inflammation and the metabolism, the Sirtfood Diet “has no real scientific evidence to back it up”. He pointed out that there’s evidence in in vitro experiments – with cells in Petri dishes – that these proteins can be affected by isolated compounds in some foods. In humans? That evidence is lacking, Molloy says. A study that showed the efficacy of the Sirtfood Diet, for example, featured in Goggins and Matten’s original book, was seemingly not peer reviewed and so Molloy is unsure whether it can even be taken as gospel.
Rupy Aujla, an NHS doctor and the founder of The Doctor’s Kitchen, was equally unconvinced of sirtfoods as a basis of a diet and found any focus on one part of our biology lacking. “If I wanted to do a new diet today,” he went on, “I could call it ‘the NRF2 diet’ because I’ve got this list of foods and they impact on this inflammatory pathway that has been purported to reduce the incidence of dementia and cardiovascular disease and it reverses a whole bunch of visceral fat improvements. I could put a list of all these different ingredients down, give it to some celebrity, and it’ll make them feel wonderful, because obviously they will. It’s a bit of an Emperor’s New Clothes situation.”
“I don’t want to make you sound like too much of a prophet,” I replied, “but that’s exactly what I’m about to ask you about.”
“Oh, my God,” he said, laughing.
Molloy agreed that an NRF2-centric diet fell into the same traps as the original Sirtfood Diet: “There are extremely healthy aspects of including these foods into your diet. To say that you should only eat these foods for one-week periods throughout your life is just taking it too far.” Aujla also found the diet’s specific food list unnecessarily restrictive. “It gets people thinking about food in an interesting way and how food can interact with our physiology – in this case, sirtuins – but there are a whole bunch of other pathways that your humble carrot or apple or savoy cabbage can also influence,” he explained. “It’s distracting from the answer, which is finding a way of eating that is sustainable for the long term.”
Mike Molloy also found the fact both the Sirtfood and Vital Diets required such a heavy calorie deficit to be incredibly dubious. “One thousand calories per day is not really sustainable for most human beings. It’s just on the borderline of a medically supervised starvation-based experiment,” he explained. Registered nutritionist Rob Hobson agreed: “If you’re a six-foot-tall bloke and you want to increase your time in the gym and be really, really active, I just don’t think it’s enough food. I think it’s really, really quite restrictive.” They said that the 1,500 calories I was on for the Vital Diet was absolutely part of the reason my workouts had been affected.
For both of them, the quick weight loss of the first week was pretty inevitable. “That’s probably water you’re losing, to be honest,” said Hobson. “It’s like that show The Biggest Loser,” agreed Molloy. “People lose insane amounts of weight in that first week and then it slows way down from there.”
While the actual food list for the diet is far from unhealthy, everyone agreed, the calorie deficit is not suited for everyone and their lifestyles and, on top of that, eating like this is simply unsustainable over long periods of time. While there is evidence to suggest fasting and caloric cutting can extend life in studies on mice, said Molloy, “they starve them every other day. So imagine only eating 50 per cent of the days for the rest of your life. And if you decide to stop from that process, all the benefits are essentially gone at that point.” To all three experts, doing anything for a week didn’t, to them, suggest it would have any long-lasting impacts on an individual’s life. “Nothing that you do for one week is going to impact you in 12 months’ time,” concluded Molloy, “never mind 12 years.”
As previously said, there is no reason not to try the Vital Diet for a week, experience it as part of KX’s really excellent and broad health and fitness offering, and take away some recipes from it that might add some new healthy meals to your repertoire. It might just be the diet that changes how you eat for good, but it wasn’t that for me. I’ve kept hold of the menu and I’m sure I’ll be trying out some of the salads, flavour combinations and ingredients it introduced to me that week for a long time to come. And if those continue to have a benefit for my NRF2 system? All the better. But diets this brief, and this specific, are probably not the way forward if you’re looking for meaningful, long-lasting change. “You’ve got a really long life to live,” added Hobson. “Are you really honestly going to eat this weird diet for the next 50 years? And if the answer’s no, then why the hell are you trying to do it now? Just get your diet on track.”