VALTER Longo is not your average scientist.
A genial Italian in his late 40s, he is professor of gerontology and biological sciences at the University of Southern California, but is also the man behind the revolutionary research that pre-empted the biggest dieting craze in recent years: fasting.
Longo shot to scientific stardom following the 2012 broadcast of the BBC’s Horizon programme Eat, Fast, Live in which presenter Dr Michael Mosley outlined the benefits of fasting based on the scientist’s research.
Watched by 2.5 million viewers hungry for a diet that delivered on every front, including longevity, the content of that documentary resulted in Mosley’s best-selling Fast Diet book, written with Mimi Spencer, and a host of copycat alternatives.
Yet Longo could see that continued, intermittent fasting had its shortfalls.
“Strict fasting is hard for people to stick to and intermittent fasting with low calories is a lot for people to handle,” he says.
“People cheat, they feel it’s too hard.”
And now his research has come up trumps with a far more convenient fasting diet, one that works as well as the weekly version, but that requires you to cut your calorie intake for only five consecutive days yet lose up to half a stone in the process.
Longo describes his latest take on temporary food deprivation as the “fasting-mimicking diet” (FMD).
Even the most reluctant dieter can understand its rules: consume 1,100 calories — roughly what’s provided in a generous serving of chicken breast or salmon with rice and vegetables and a yoghurt — on the first day and about 750 calories — a stir fry made with noodles and chicken, for example — for the next four and you are done.
You can eat pretty much what you like for the rest of the month.
Should you prefer a pre-set plan, then Longo is launching his own version – the ProLon meal plan delivered to your door for around €250 per fast.
It’s a combination of soups, crackers, health bars, supplements and energy drinks formulated to be low in sugar but relatively high in complex carbs and healthy fats.
Unusually for a man who promotes food denial as a means to healthy living, Longo loves his food.
He wouldn’t want to stick to a regimen that was so restrictive it made him miserable, he says, and wants to “enjoy eating normally” as much as he can.
And so, using laboratory mice, Longo demonstrated how a fasted state resulted in a drop in levels of a hormone called insulin-like growth factor 1 (IGF-1), high amounts of which are linked to cancer and accelerated ageing in later life.
“Over the last 20 years, a tremendous amount of work has shown that, by reducing food intake to trigger a drop in levels of certain hormones, the body responds by regenerating healthy cells and getting rid of damaged or unhealthy ones,” he explains, likening our bodies to steam trains that burn fuel to the very bottom of supplies to enable maximal refueling at the next station.
“By emptying our body’s reserves occasionally, we are able to rebuild cells so that they are stronger and better able to withstand disease,” he says.
Everyone I know has tried fasting.
Call it what you will – IF (intermittent fasting), the 5:2 or the Fast diet – the premise of the trend that has satiated our voracious appetite for dieting over the last few years remains the same: cut your calorie intake to minuscule amounts twice a week and you can relieve yourself of dietary starvation the rest of the time.
It’s appeal has always been its simplicity.
Men have loved if for that as much as women and we have all relished not just the accelerated and sustained weight loss, but the promise of improved health and a longer life that comes with sticking to it.
But five years after it revolutionised our approach to eating, there are signs that the monotony of on-off fasting is starting to take its toll.
For all the practical advantages it holds over predecessors like the Dukan and Atkins diets, it still requires a shedload of self-discipline to subsist on the two meals of roughly 250 to 300 calories each — roughly the equivalent of a boiled egg, a slice of toast and a small spoon of baked beans — depending on the person’s sex (500 calories for women, 600 for men) that comprise a typical fasting day.
Female friends tell me they started to get tetchy on the relentless 5:2 cycle and many now do it only when a holiday or wedding looms.
“It made me dizzy and dehydrated,” says one woman I know.
Men are just tired — not only of the routine, but physically, as a result of the energy slump that comes with eating just an egg, an oatcake and a single slice of ham for breakfast.
Longo’s five-day FMD diet is, in effect, a cheat’s fast, one that achieves the same effects as the 5:2 approach, but that can be slotted into even the most hectic lifestyle with poetic ease.
Certainly, Longo’s findings are compelling, the most recent suggesting the five-day fast may prove to be a cure for Type 2 diabetes.
Published in the journal Cell in February, Longo and his team showed how the five-day diet appeared to ‘reboot’ the bodies of mice with types 1 and 2 diabetes, both of which are characterised by problems regulating blood sugar levels due to difficulties in producing or responding to insulin.
“The cycle of fasting meant we were able to demonstrate how non-insulin producing cells could be regenerated into insulin-producing cells,” he says.
Even mice in late stages of the condition saw cells re-programmed so that they functioned effectively.
Other researchers have shown similar benefits of fasting on type 2 diabetes prognosis and, with larger trials planned, the evidence seems ever more convincing.
Longo stresses it’s not without risks — “No diabetes patient should self-administer a fasting diet and it should not be tried even with the help of a doctor since most doctors may not realise that its combination with insulin and other drugs could be very dangerous” — he is confident it has future uses for diabetes and other medical issues.
In another trial published last month, Longo and his colleagues randomly assigned 100 healthy adults, only a small number of whom had significant weight to lose, into a group that followed his FMD and a control group.
All of the participants underwent a battery of tests, with the five-day fasters showing improvements in a range of metabolic markers linked with ageing and diseases, such as fasting glucose, cholesterol and blood pressure.
Additionally, their levels of IGF-1 and C-reactive protein, a risk factor for cardiovascular disease, had gone down.
On all of the research programmes, weight loss is a welcome side effect, with participants shedding an average 5.7lbs in one to three months.
“If you have excess weight to lose, the drop will be greater,” Longo says.
“If you don’t, then it’s more about maintaining weight and improving health.”
Total body fat, trunk fat, BMI and waist circumference are also significantly reduced on the plan.
It’s a format that has now been tested on almost 4,000 people and Longo says people are continually drawn to the approach not just because of fat-shredding, but because it’s less risky and hardcore than a full-blown fast.
“We still don’t know how safe long-term fasting is,” he says.”
We do know that there are some risks, such as gallstones, with frequent fasting of more than 12 hours duration, but there may be other side effects we don’t know about yet.”
Last year, a study published in The Lancet medical journal showed that, along with Britain, Ireland is set to become the most obese country in Europe, within a decade.
Irish men already have the highest body mass index (BMI) — a key measure of overweight —in Europe, while Irish women rank third, the study revealed.
According to Healthy Ireland, there are well in excess of one million adults in Ireland who need to consider making healthy changes to their lifestyles and diets.
The organisation says there are 854,165 adults over 40 who either currently have Type 2 diabetes or at a high risk of developing it because they are overweight.
More alarmingly, there are a further 304,382 in the 30-39 year age group that are overweight.
But is it recommended we jump on to the five-day fast?
Longo stresses that nobody with Type 1 or Type 2 diabetes should ever fast, or attempt a diet, without seeking medical advice first.
Aveen Bannon, a dietician and nutritionist based at the Dublin Nutrition Centre, agrees.
“Definitely anyone with Type 1 diabetes should avoid this diet completely,” she says.
“Also it’s not recommended for anyone who is active, has osteoporosis or is a growing teenager.”
She is hesitant about its benefits.
“The approach will result in an overall calorie reduction over a seven-day period so of course you will lose weight,” she says.
“But, to be honest, I’m not a fan of strict regimented diets. When you have some days of very low calorie intakes you run the risk of not meeting nutritional requirements on those days”.
Bannon falls shy of saying it’s dangerous, but wouldn’t recommend it.
“Firstly, I think it would be difficult to preform work wise or exercise without fuelling ourselves properly,” she says.
“And, secondly, it is not a long-term healthy plan.”
However, others are more open to the concept that it could improve our health —and our waistlines.
“Fasting has its advocates,” says Paula Mee, a dietician and past president of the Irish Nutrition and Dietetic Institute.
“Krista Varady, an associate professor of kinesiology and nutrition at the University of Illinois at Chicago, found that those in the alternate-day fasting group lost approximately 1lb per week and experienced cardioprotective effects at the end of treatment. She also found that alternate-day fasting seemed to help lower diabetes risk.”
While Mee says it can leave you tired and struggling to concentrate in the short term, a mini fast might be a reasonable approach for some people.
“Depending on your age, health and lifestyle, semi-fasting could be good or bad,” she says.
“If you want to go down the fasting route, it is important to choose an evidence-based plan and consult a medical professional to ensure that this is done in a healthy and safe way.”
For those with 5:2 fatigue who are on a fasting mission, it certainly seems an easier and in many ways more digestible option.
While you need to fast for five days on the trot, the calorie allowance of 1,100 or even the 750 allowed on the most extreme days is more generous than the paltry 500 permitted on the 5:2.
And Longo says you needn’t even do it that often— for a normal weight person with no heath issues, the health benefits of a single five-day fast can extend to several months which means it is short-term torture for long term gain.
What’s certain is that your dress size will drop even after one five-day fast.
And that, surely, is a motivation in itself.
1. “Anyone interested in trying this approach should firstly check with their GP or specialist to ensure it is safe for them to do so,” says Paula Mee. Do not attempt it if you have diabetes or if you are feeling unwell.
2. Set aside five days when you know you will able to tackle the fast without too much stress. “You need to pick a time that is right for you,” says Longo. “If you have a lot of work or social engagements, then postpone it.”
3. Invest in a calorie counting book or app. It will help with meal plans: 1,100 calories on day one and 750 calories daily for four days.
4. Plan your meals in advance. You are far less likely to stick to the allotted calories if you decide what to eat at the last minute.
5. Steer clear of refined carbs like white pasta and rice, cakes and biscuits as they will not sustain you. Wholemeal versions are far better.
6. You are permitted water, black coffee and tea on a fast – just make sure you don’t add flavourings, milk or sugar. Stay hydrated — often the headaches that are a common side effect of fasting are the result of dehydration.