Diet fads are as old as humankind itself. In 175 BC, the Roman statesman Cato advocated the virtues of eating plenty of cabbage.
Fast forward to this century, and cabbage soup diets are still used by those in search of the holy grail of weight loss -although, in terms of popularity, they've been supplanted by Dukan, South Beach, the 5:2, Paleo, alkaline and blood type diets, to name a few.
If we've become inured to the sometimes 'miracle' claims made by campaigners for diets, a new development has turned certain cornerstones of nutritional science on their head. For many years, the importance of a low-fat diet was drummed into us; now that 'official advice' is, we are being told, both dangerous and incorrect. Instead it is sugar that is deemed public enemy number one.
The latest nutritional sacred cow to come under attack is breakfast, seemingly the "most important meal of the day".
In a new book, however, the British professor Terence Kealey, whose background is clinical biochemistry, says that it's potentially lethal.
Breakfast is a Dangerous Meal makes a convincing argument for skipping eating first thing, and its publication comes alongside a recent study from the UK which found that school children are consuming half of their recommended sugar allowance at breakfast because of fruit juices, spreads and sugary cereals.
When we eat breakfast, Kealey argues, we're increasing the amount of calories we consume, we're creating hunger pangs later in the day, aggravating the metabolic syndrome (which raises risk of heart disease, stroke and diabetes), and, in all likelihood, eating far too many carbohydrates, breakfast being a meal that tends to centre around toast, pastries and cereals.
Kealey's own interest in the topic stemmed from personal reasons. In 2010 he was diagnosed with Type 2 diabetes and was told to "eat a good breakfast". But he discovered, via a glucometer, that his blood glucose levels were alarmingly high in the mornings (over time this can lead to serious complications for people with diabetes) and would rise much further after eating breakfast.
When he skipped breakfast, his levels fell to normal and would rise a little after lunch and dinner, but noticeably less than after eating in the morning. His conclusion: the advice he had been given was wrong and could potentially hurt him, so he set about investigating the science of breakfast.
In the book, he assails all that we cherish to be true about the 'all-important' meal: that it's good for the brain; that people who eat breakfast are thinner than those who don't; that it kick starts your metabolism. He also looks at how breakfast is a big business and how many studies supporting the health claims of a morning meal are funded by cereal or other breakfast food manufacturers. In one chapter he examines misleading experiments, and the systematic bias of the research papers he studied surprised him.
"I never encountered a single example of dishonesty and I read hundreds of papers," he says. "However, I read paper after paper after paper in which I was astonished by the degree to which the scientists were obviously fooling themselves. The scientists had clearly approached this problem with a preconception and whatever data they found, they moulded their conclusions."
He added: "People engage in what scientists call 'paradigm protection'; they intuitively behave in confirmation bias and try to find evidence to support because it's so hard to acknowledge error."
The book's message is unequivocal: from reduced blood pressure to weight loss and greater life expectancy, not eating breakfast is the healthiest choice. There are two exceptions: professionals such as pilots and surgeons who are responsible for other people's lives (although he warns them that they are shortening their own) and the 'privileged minority' - AKA the slim, fit and young - may eat first thing.
Overall, he recommends a diet devoid of sugar and refined carbohydrate, as well as avoiding red and processed meat (these are inflammatory, which is linked to hardening of the arteries and Type 2 diabetes), steering clearing of processed foods in general and eating lots of plants.
"We're asking too much of the body to expect to eat three delicious meals a day," he says. "If you can go to two delicious meals a day then suddenly, you're giving your body a chance because you're giving it that morning to recover from the day before and that morning fast is really very important for the body to recover."
According to dietitian Sarah Keogh of Eatwell, the idea of skipping breakfast isn't a new one.
"There's a trend around some nutritionists where they talk about eating just for a few hours a day and the idea is that there is only so much food you can fit in. Often in that scenario, people will skip breakfast and might only eat from 10am through to 8pm in the evening and it does seriously limit the amount of food they can eat," she says. "I have to say from years of working with people who are losing weight, I tend to be a fan of whatever works. I generally tend to encourage people to eat breakfast but if for some reason, that's going to work differently, let them off."
Her issue with skipping breakfast is from a nutritional as opposed to a weight-loss viewpoint. "Studies looking at women find that women who skip breakfast rarely make up the iron that they need during the day, or they miss out on B vitamins and everybody misses out on fibre," she says.
She also warns against demonising carbohydrates. "It's one aspect of nutrition and people forget that a healthy diet has so many nutrients involved. What people tend to do is that they pull out one - 20 years ago, people went on about fat in the way that they go on about carbohydrate today."
She maintains that carbs haven't solely caused the obesity crisis, pointing to our sedentary lifestyles, lack of sleep, changes in our gut bacteria and 'casual eating'.
Keogh says: "What we do know about carbohydrates is that if you go for unrefined, high-fibre carbohydrates, that's very helpful because fibre is really incredibly effective in terms of managing weight."
There is one small consolation. Kealey is not going to upset those who are addicted to their brunch fix - in fact, he's a fan of the meal.
"Most of us eat quite healthily at weekends, we'll have a lovely brunch and a nice supper and I think that's a great way to live," he says.
If you absolutely can't survive without your morning meal, Professor Kealey says the ideal breakfast would probably be a boiled egg, followed by strawberries and cream, strawberries having a lower glycaemic index than other foods.
Dietitian Sarah Keogh has a trinity of foods she thinks should make up a healthy breakfast. "It's very good to get the wholegrain in, because we know that it helps reduce heart disease and they have antioxidants and B vitamins.
"Secondly, I would always look to get some sort of fruit or vegetable in there, something as simple as a banana or a few berries. And then some protein - nut butters like peanut or almond are fantastic and some people like an egg in a morning. Seeds are also brilliant, such as a couple of teaspoons of sunflower seeds into your porridge.
She adds: "It's more about striking a balance, so a breakfast such as poached eggs with wholegrain toast and tomato or spinach is a good choice."
Health & Wellbeing
There are times, in our awfully busy lives, when we are not as prepared as we would like. It's during those moments where we opt for takeaways or rely heavily on the foods that we keep within our homes. We want to stick to the latter, so here are some cupboard essentials that you should buy on your next trip to the supermarket so you can throw together a nutritious meal at short notice.