Last year I came across a Facebook forum for people practising a form of Intermittent Fasting (IF) known as OMAD. One Meal A Day? It sounded unsustainable and extreme. Who could stomach that? A few months on, this April, we discovered exactly who when Twitter CEO Jack Dorsey revealed he eats one meal a day in a short early evening three hour window.
The response to news of Dorsey’s diet was uniformly negative. Rolling Stone called it, “Bonkers”. But my thinking, by then, had changed, fasting has a new found credibility, not just from the actual science, but also from the cherry picking amateur enthusiasts bolting from the Internet and the celebrity stable. Intermittent Fasting has been endlessly hyped by lad hero, comedian and megastar blogger, Joe Rogan, and a predictable parade of Hollywood specimens achieving perfection for their latest movies. Virgin Radio DJ Chris Evans confessed last week he’d converted to fasting 12 hours at minimum and sometimes for as much as 16 hours, confining his eating to an 8 hour window (known as 16:8).
In its annual survey of American dietary habits by the International Food Information Council, Intermittent Fasting came top in 2018 and was narrowly beaten only by the ambiguous ‘clean eating’ in 2019. A raft of apps have emerged to help people manage their new fasting lifestyles, one of the most popular, Zero, announced in August it had 2.5 million downloads since it launched in two years ago.
In evolutionary terms and physiologically, OMAD isn’t as loony as it first seems. There are credible, scientifically-backed arguments to suggest that we are suited to eating far more healthy fats and much less regularly than late 20th Century and, indeed, existing government dietary advice suggests.
Scientists at the Salk Institute found the average person’s feeding window to be about 15 hours long, from that first frothy cappuccino to the last little biscuit or the whiskey before bedtime. Eating exactly the same obesogenic, read sugary, diet, mice with access to food 24 hours a day were carrying four times the body fat of mice eating exactly the same quantity of food for only eight hours a day. The Institute’s 2018 study concluded that, “eating in 10-hour window can override disease-causing genetic defects and nurture health”.
However, that was not all that interested me. Studies suggest that a phalanx of health issues, like Alzheimers, cancer, polycystic ovary syndrome and the 21st Century’s top grim reaper, metabolic syndrome, respond positively to us eating less often. For more day to day health issues, blood tests prove that many health markers including cholesterol, blood sugar levels, inflammation, human growth hormone and a brain performance protein called BDNF can be positively impacted.
Less scientific are claims that it will take the human body into a state where it starts to eat its own dead and damaged - read cancerous - cells after about 16 hours. This state is known as autophagy and the latest advances in understanding this process won Yoshinori Ohsumi the Nobel prize in Physiology or Medicine. However, despite promising animal studies, so far nothing scientific has actually shown when it kicks in in fasted humans.
Annie Hart, 49, a health coach, usually fasts for 16 hours at a time, but finds OMAD even more effective: “Within a week of doing OMAD my brain had woken up, I was less depressed and foggy. I thought I was starting the menopause but turns out I was not, it was how my body was reacting to food.
“I know OMAD is not for everyone. Having said that, it worked so well for me that I now have my 90 year old father thriving on a two meal a day protocol. I firmly believe everyone should fast for at least 12 hours (best often overnight).”
One of the most high profile proponents of fasting is Dr Jason Fung, a fasting expert whose Toronto Metabolic Clinic treats metabolic disorder with fasting and ketogenic (high fat) diets.
In his book, The Obesity Code, Fung recommends high fat, medium protein and low carbohydrate meals, spaced many hours apart. When we eat, insulin goes up, instructing the body to store food as body fat. When we don’t eat, insulin goes down, signaling the body to burn this stored fat. Fasting, properly managed, is a sure way to lose weight.
Nutritionist Petronella Ravenshear, 62, is the author of The Human Being Diet, which she describes as a “A blueprint for feasting and fasting your way to feeling, looking and being your best.” She says she naturally thrived on OMAD for most of her adult life, until, ironically, being forced into what she sees as the three meals a day with snacks dogma while she was training to be a nutritionist, which made it far harder for her to go back to her OMAD habits, “When I do, it’s always worth it.”
She sees the benefits of OMAD as mimicking, “The metabolic flexibility in the hunter-gatherer lifestyle versus the metabolic inflexibility of the modern sedentary lifestyle. When we fast, i.e. when we stop eating for extended periods, which was very common for Paleolithic man, the brain is forced into pulling energy rather than storing energy mode and that’s good for us.”
It all sounds grand, so why aren’t we all at it? In a word, hunger. In my early attempts at OMAD I followed Ravenshear’s recommendation that I give my body a complete rest from eating, and to drink only water. I felt desperately denied, a tad deranged even. I managed only 16 hours at the most, food free - the last four of which were a white knuckle ride of insane longing for a milky coffee with toast and eggs. This continued for a few weeks and I found any excuse to break the fast. Obviously I was not a natural OMADder, like Ravenshear.
These hunger pangs disappeared when I read Dr Jason Fung’s, A Complete Guide to Fasting, which recommends I ward off hunger with homemade bone broth, a couple of chicken carcasses cost 70p from the butchers, and I boiled them for a couple of hours with herbs and veg, strained it, which I drank with added salt (for the electrolytes). After that, with a bit of black coffee and green tea, incredibly, the day passed with very little thoughts of food at all. This was my OMAD epiphany. Now I find 18:6 doable most days. If I’m busy and running about, 20:4 is a cinch. Any sign of high stress or a hangover, though, and my eating returns to chaotic.
Yes, a word of warning to drinkers. All the eating chaos and rabid hunger always returned after a night of drinking more than two glasses of wine and after a 50th birthday my eating fitted less into a window and more into patio doors flung wide open. The snacking returned as did the lack of focus. For this reason, I think a more civilised 16:8 lifestyle is probably best for me. Some days when OMAD went wrong my eating was without question verging on bingeing, and that is what makes eating disorder professionals concerned about OMAD and the other more extreme IF trends.
British Dietician Associaton’s spokeswoman, Priya Tew, is dismissive of such extreme fasting: “It is unsustainable long term, so it is a crash diet, which could potentially lead to gaining any weight lost, and more.” Having said that, reasonable restricted eating windows are, Tew says, a good thing. “It is a good idea to stop snacking and focus on meal times for breakfast, lunch and dinner. And there’s nothing wrong with skipping breakfast if you’re not hungry, as long as you aren’t compensating by eating more mid-morning.”
Deanne Goddard of the National Centre for Eating Disorders gives OMAD short shrift. “The kind of people attracted to these diets also have poor body image and although they claim that they are restricting their food for health, they’re probably over focused on appearance. People who live most happily are those who practice moderation, not extremes of any form. They do not impose pain on their bodies to achieve their life goals. It’s well-proven food restricting diets lead to bingeing and that rigid dieting systems have a negative impact on both self-esteem and the way we view feel and behave around food.”
I mention autophagy, and she says, “I believe they are based on pseudo-science because no one has taken into account the negative impact food restriction of any kind has on the neuro-chemicals in the brain that govern appetite and mood.”
The problem with replicating the eating patterns of Palaeolithic man is that unlike back in the Stone Age, food is in plentiful supply. Had Paleolithic woman come across a big bag of Burt’s Crisps in her cave she would have stuffed them all down too. Bingeing is a natural animal response to hunger. No matter how thrilling the science in its favour, until we live in a world without wine and Burt’s crisps, fasting will remain peppered in edible pitfalls.