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PARIS — Why have some birds opted for a taxing life of constant migration — seeking out temperate climes to feed as winter arrives, only to return months later to breed?

Seemingly paradoxically, the behaviour is driven by a quest for energy efficiency, a study said on Monday. 

Migrating birds, researchers found, gain more energy from whatever is on the destination menu than they expend getting there and back, or could find without making the trek.

Why do not they just stay in the warm place? Because there is too much competition for food with other species, said the study published in the journal Nature Ecology and Evolution.

Instead, they return to their cold, northern hemisphere home where they do not have to fight others for the food there is.

The work “provides strong support for the hypothesis that birds distribute themselves in an optimal way in terms of energy”, study co-author Marius Somveille of the University of Oxford’s zoology department told AFP.

While it was known that birds migrate in search of food, it has remained a puzzle why they have adopted this exacting lifestyle.

The new study explains the behaviour of not only migratory birds, but also that of sedentary or “resident” ones, its authors said.

These too weighed the available food against greener pastures and came to a different conclusion. Most resident birds are found in the tropics, where food is easier to get by.

The study used a theoretical model to examine why birds migrate — about 15 per cent of the total — while others do not.

It started with a model world with similar climatic differences between regions than our real one.

The researchers then added virtual birds, and the estimated amount of “energy”, or food, available in different regions.

Given these inputs, the model birds dispersed very similarly to what happened in real life.

The birds started off in the food-rich tropics, but growing competition forced some to start moving further afield.

“In our increasingly crowded virtual world, species progressively started exploiting more extreme pockets of seasonally available energy supply, often migrating longer distances,” the team wrote.

The model adds to our understanding of how Earth’s plants and animals came to be distributed as they are, the researchers added.

It could also be useful in predicting the future movements of other animals — to determine how they might migrate in response to global warming, for example.

For teen girls, being called “fat” by friends or family may contribute to later developing eating disorders, and the harsh word from family members seems to carry the most weight, a recent US study suggests. 

Weight stigma — the negative stereotypes, social devaluation and pervasive mistreatment of heavier individuals — is strongly implicated in disordered eating, the research team writes in the Journal of Adolescent Health. 

Previous studies have found that being teased about weight is associated with binge eating and unhealthy weight control behaviours in boys, and increased dieting in girls. The current study is one of the first to look at the long-term consequences of being labelled as “too fat,” the authors note. 

“How we talk about weight — especially with young girls — can have really negative effects on mental and physical health”, said lead author Jeffrey Hunger, a psychologist at the University of California, Los Angeles. 

“Labelling young girls as ‘too fat’ will never spur positive health behaviours; it is simply going to result in poor body image, unhealthy weight control practices, and disordered eating,” he told Reuters Health in an e-mail. 

There is a lot of research showing that weight stigma is related to disordered eating, but not much of it follows people across time, Hunger said. 

“With this study, I was hoping to contribute to our understanding of these longitudinal consequences by leveraging data from the National Heart, Lung, and Blood Institute Growth and Health Study.” 

Hunger and a colleague examined data on 2,036 girls participating in that larger, long-term study. At age 14, the girls reported whether they had been told they were “too fat” by their parents, siblings, best girlfriends, boys they liked best, any other teens or their teachers. 

At ages 14 and 19, the girls completed a questionnaire designed to assess unhealthy weight control behaviours, bulimic tendencies, drive for thinness and body dissatisfaction. At both evaluations, girls reported whether in the past 30 days they had engaged in unhealthy behaviours such as not eating, vomiting, taking diet pills or using laxatives; at age 19, they were also asked about smoking and skipping meals as weight control methods. 

Compared with girls who did not report having been labelled fat at age 14, girls who were weight labelled at 14 had higher scores at age 19 on the eating disorders inventory, researchers found. 

This association held after the study team adjusted for other possible influences, such as body mass index, race, parental income and education, and a girl’s level of disordered eating behaviours at age 14. 

The study also found that weight labelling by a family member was a stronger predictor of later disordered eating than labelling by nonfamily members. 

“A somewhat surprising [yet frequently observed] finding is that the effects of weight stigma emerged independent of actual body size,” Hunger noted. 

It seems that there is something profoundly powerful about the social implications of being labelled “too fat” that is not limited to heavier girls, he said. 

“That being said, heavier girls do disproportionately shoulder the burden of weight stigma, and stigma against heavier bodies is pervasive and systemic, so we should take care not to equate this to thinner girls’ experiences of weight labelling,” Hunger added. 

First and foremost, if a parent suspects their child may have an eating disorder, they should have the child assessed by a specialist. Beyond that, parents can promote positive body image and healthy eating behaviours in a variety of ways, he said. 

“They can take weight out of the conversation altogether when they are discussing health with their children. Our weight does not dictate our health and most certainly does not dictate our worth.” 

Parents can also model body positivity and health behaviours for their kids, Hunger suggested. 

“Quit the negative ‘fat talk,’ chronic dieting, and body shame. Recognise and appreciate all that your body can do for you and find eating and exercise habits that are sustainable and enjoyable,” he said. 

The compound that I live in is infested with domestic pets. In the fifty odd houses around my neighbourhood, it seems like there are an equal number of dogs there. These animals have strong vocal chords and the cacophony they produce when I walk past the villas, is overpowering. 

I do not know how many of you have noticed this, dear readers, but the smaller the dog; the more ferocious its bark is. It is almost as if the canine tries to cover up for its dainty size, by its fierce growl. In fact some of the Chihuahuas — the smallest breed of dogs that are named after the state of Chihuahua in Mexico — are so easily provoked that when they bark, their entire body shakes in fury.

The lane that leads out of my bungalow has dogs only in the houses on the left, so with a little bit of manoeuvring, and following the footpath on the right, I manage to avoid unpleasant encounters. But once I turn the corner, all hell is let loose and this street, in all fairness, should be named “Le Chien” instead of Le Fontaine because whether you understand French or not, this is definitely dog territory.

Mongrels of all shapes and descriptions inhabit this area and a volley of barks accompanies my every step. They run towards the fence and jump on it with their paws, snarling and outshouting each other. My efforts of pacifying them with a “good dog”, “nice dog”, falls on deaf ears and I wonder why these pets have not undergone any training.

Our own Golden Retriever, who was called Zar, followed my instructions perfectly. We lost him a few years ago but whether it was, “stop”, “sit” or ‘stay’ command, he never faltered, not even once.

“It is all to do with the correct tone of your voice,” Zar’s trainer, who was a South African lady, had explained to me. “Used with the right gestures, the animals are bound to obey,” she had emphasised. 

I recall this while walking past the barking dogs. My biggest fear is what might happen if these beasts came bounding out of an open gate. I have left my sprinting days far behind, I am well aware of that. There is not a chance in hell that I can outrun them. “Maybe I should carry a stick with me when I go for a walk,” says the voice in my head. 

My family offers me helpful suggestions like climbing up the nearest tree or asking our driver to follow me in the car, in case I find myself being chased by a dog. I know they are making fun of me so I decline politely. 

But one day my worst horror comes true. Even as I keep to my side of the lane, two extremely angry dogs come storming out of their open enclosure. I get rooted to the spot as they charge towards me. A vision of fourteen injections on my stomach floats in front of my eyes.

“Stop,” I say firmly, holding my palm up.

I imitate the voice of Zar’s South African trainer. 

The dogs cease barking immediately.

“Sit,” I command, willing myself to stop trembling. 

The two dogs sit down. 

“Stay,” I announce authoritatively.

Both of them lie on the ground. 

“Stay,” I repeat, stepping back slowly.

By now the dogs are smiling. 

One of them is even wagging his tail. 

“Good dog,” I murmur, rushing off.

MOUNTAIN VIEW, California — Google unveiled on Tuesday an artificial intelligence (AI) tool capable of handling routine tasks — such as making restaurant bookings — as a way to help people disconnect from their smartphone screens.

Kicking off the tech giant’s annual developers conference, Google Chief Executive Sundar Pichai argued that its AI-powered digital assistant had the potential to free people from everyday chores.

Pichai played a recording of the Google Assistant independently calling a hair salon and a restaurant to make bookings — interacting with staff who evidently did not realise they were dealing with AI software, rather than a real customer.

Tell the Google Assistant to book a table for four at 6:00 pm, it tends to the phone call in a human-sounding voice complete with “ums” and “likes”, and sends you a message with the details.

“Our vision for our assistant is to help you get things done,” Pichai told the conference in Google’s hometown of Mountain View, California.

“It turns out that a big part of getting things done is making a phone call.”

Google will be testing the digital assistant improvement in the months ahead.

“Many of us feel tethered to our phones and worry about what we’ll miss if we’re not connected. We want to help people find the right balance and gain a sense of digital wellbeing,” Pichai said.

Getting things right

The conference opened with Silicon Valley facing a wave of criticism over issues such as private data protection, the spread of misinformation and the use of tech platforms for hate speech and violence, and with intense scrutiny of Facebook over the hijacking of data on millions of its users.

“It’s clear that technology can be a positive force and improve the quality of life for billions of people around the world.” Pichai said. 

“But it’s equally clear that we can’t just be wide-eyed about what we create.”

He added that “we feel a deep sense of responsibility to get this right”.

Much of the focus was on Google Assistant, the AI application competing against Amazon’s Alexa and others.

Pichai launched an overhaul Google News venue that put AI to work finding trusted sources for stories and balancing perspectives to provide fuller pictures of breaking developments.

“It uses artificial intelligence to bring forward the best of human intelligence — great reporting done by journalists around the globe — and will help you stay on top of what’s important to you,” Pichai said of overhauled Google News.

And, evidently popping news “bubbles” created by tailoring results to what people want to hear, everyone will be shown the same content on topics, according to product and engineering lead Trystan Upstill.

Google Assistant is also being taught to better understand people and interact with them more naturally — and will be getting new voices, including one based on the voice of singer John Legend, as well as programming to improve conversation performance.

“Thanks to our progress in language understanding, you’ll soon be able to have a natural back-and-forth conversation with the Google Assistant without repeating ‘Hey Google’ for each follow-up request,” Pichai said. 

More ‘shush’ time

In another effort to untether people from smartphone screens, a dashboard breaks down time spent on devices and how often they are unlocked.

Google also planned to add a “shush” mode to its Android mobile software, switching smartphones to a do-not-disturb mode when they are placed face down on a table.

YouTube watchers will be able to set a pop-up message to remind them to take breaks from viewing, according to Pichai.

“This is going to be a deep, ongoing effort across all our platforms,” Pichai said.

“To help you understand habits, focus on what matters, switch off and wind down.”

Google is seeking to make services more personal, relevant and intimate from maps to e-mail, Gartner analyst Brian Blau told AFP after the keynote presentation.

“The are taking a very human approach to technology, and convincing you people can continue to rely on Google,” Blau said.

“We have seen, as a central theme, trust.”

BONN, Germany — Tourism is responsible for a twelfth of world greenhouse gas emissions, and a vacation boom is complicating a global drive to slow climate change, scientists said on Monday.

Emissions from tourism, mostly by domestic travellers, were highest in the United States, China, Germany and India, according to a review of 160 nations led by the University of Sydney and published in the journal Nature Climate Change.

Tourism, including flights, hotels, food and even the production of souvenirs, emitted the equivalent of 4.5 billion tonnes of carbon dioxide in 2013, the most recent data available, or 8 per cent of all man-made greenhouse gases, up from 3.9 billion in 2009, it said.

That was far above many previous estimates, using narrower definitions, that tourism accounts for just 2.5 to 3 per cent of world emissions, it said.

And on current trends, the $1 trillion tourism industry will emit 6.5 billion tonnes of carbon emissions by 2025, the review said, making it one of the fastest-growing source of the planet-warming gases that governments are trying to cut.

Flights were the biggest single contributor, according to the study by scientists in Australia, Taiwan and Indonesia.

“We recommend flying less and staying Earth-bound where possible, e.g. use public transport,” co-author Arunima Malik of the University of Sydney told Reuters in an email.

Lead author Manfred Lenzen said plane tickets would have to be far more expensive to reflect the harm caused by greenhouse gas emissions from burning jet fuel.

“If I flew from Melbourne to the UK return, I would pay at least an additional A$205 ($150) to offset my emissions; for a return trip between Sydney and Brisbane, about A$18 extra,” he wrote in a news release.

Almost 200 nations are meeting in Bonn this week to write a “rule book” for the 2015 Paris Agreement, which seeks to slash greenhouse gas emissions to avert more heat waves, downpours, droughts and extinctions.

Patricia Espinosa, head of the UN Climate Change Secretariat hosting the talks, said the tourism industry itself was making “good progress” to clean up.

“A lot of what the industry is selling depends on the preservation and conservation and the protection of the environment,” she told a news conference. 

The study added up all emissions from tourism but did not try to compare how a holiday compared with staying at home, where people also emit greenhouse gases, through everything from heating to commuting.

Even light drinkers who enjoy a single beer or glass of wine every night may still be more likely to die prematurely than people who drink less, a recent study suggests. 

Compared to people who drink less than 100 grammes of pure alcohol a week — roughly the equivalent of five to six glasses of wine or beer — those who consume 100 grammes to 200 grammes of alcohol weekly have an estimated life expectancy at age 40 that’s about six months shorter, the study found.

Drinking even more was associated with a greater risk of premature death. When people drank 200 grammes to 350 grammes a week of alcohol they had up to about a two-year reduction in life expectancy at age 40 compared with those who drank less than 100 grammes weekly. And people who drank more than 350 grammes a week had up to a five-year reduction in life expectancy at age 40. 

“Drinking less was associated with a longer life,” said lead study author Angela Wood of the University of Cambridge in the UK. 

While some previous research has linked light drinking to a lower risk of death, particularly from heart disease, results have been mixed and many earlier studies included some people who abstained from alcohol or stopped drinking for health reasons, researchers note in The Lancet. 

For the current study, Wood’s team examined data on almost 600,000 current drinkers who were 57 years old on average and did not have heart disease at the outset. 

About half reported consuming more than 100 grammes of alcohol a week. Slightly more than 8 per cent were heavy drinkers, consuming more than 350 grammes of alcohol weekly. 

Researchers followed half of the participants for at least 7.5 years. 

During the study, 40,310 people died, including 11,762 fatalities from strokes or vascular problems and 15,150 cancer deaths. There were 39,018 new diagnoses of cardiovascular disease including strokes, heart attacks, heart failure and deaths from other cardiovascular diseases. 

Higher alcohol consumption was associated with a greater risk of stroke, heart failure, and fatalities due to high blood pressure or a bulging or ruptured aorta. Any amount of drinking appeared to increase these risks. 

For non-fatal heart attacks, however, light alcohol consumption was associated with a slightly lower risk. 

The study was not designed to prove whether or how alcohol might directly impact the risk of specific health problems. Researchers also relied on survey data to assess drinking habits, which does not always reflect the amount people really drink. 

Still, guidelines in many countries allow more than 100 grammes of alcohol a week, and the results suggest that people should consider drinking less, Wood said by e-mail. 

“This study challenges some of the recommendations for healthy alcohol consumption, in particular for men, where we recommend up to two drinks a day in the US, twice the amount associated with higher risk of premature death seen in this study,” said Eugene Yang of the University of Washington School of Medicine in Seattle. 

“I think this study adds more uncertainty as to what is the right amount of alcohol to recommend for our patients,” Yang, who was not involved in the research, said by email. 

“I don’t think there is a simple answer, because it is not clear that there is an increased risk of premature death — these are all observational studies and we are not controlling the amount of alcohol people consume and then analysing the risk of death.” 

Still, moderation is key, said Giovanni de Gaetano, of IRCCS Istituto Neurologico Mediterraneo Neuromed in Pozzilli, Italy. 

“The difference between moderate and heavy drinking in relation to disease risk and mortality is well-established,” de Gaetano, who wasn’t involved in the study, said by e-mail. “Moderation is the key word of alcohol and health.” 

Not one partial to the adventures of Britain’s most iconic fictional gentleman spy, the opportunity to drive his car brand of choice was one a curious and highly anticipated occasion tempered by detached neutrality and devoid of sentimental preconception.

Virtually joined at the hip with the James Bond franchise in terms of public perception, Aston Martin’s DB11 Volante, however, proved that one needn’t appreciate the former to be charmed by the latter and especially so on home turf, where its fluent suspension was indispensible over “textured” British roads and quick folding roof mechanism invaluable for sudden weather changes.

Jutting and curvy

A sporting two-door 2+2 grand tourer combining adept handling, smooth ride comfort, stylish design and luxurious interior, the DB11 rides on a stiffer and lighter all-new bonded aluminium platform, and is the first of a new generation of Astons developed in collaboration with 5 per cent share-holding Mercedes-AMG, who provide a new engine and electronics.

Launched earlier this year, the driven rag-top Volante (Aston speak for convertible) version is exclusively powered by Mercedes-AMG’s 115kg lighter V8 engine rather than Aston’s in-house V12, to compensate for an additional 110kg of frame stiffening in the absence of a fixed-head roof.

Reflecting a more elegant and less aggressive profile compared to the fixed-head coupe version, the driven Volante version’s understated champagne to light beige launch colour little disguised the DB11’s exoticism. Judging by the overwhelmingly positive reactions it stirred during test drive on UK roads, the softer hue may, however, have taken some of the edge off of any perception of arrogance.

But regardless, it is all too easy to appreciate the beauty of the Volante’s low-slung form, and curvy Coke bottle hips juxtaposing its jutting front and rear fascias, vast gaping front grille, and slim U-shaped rear lights.

Burbling and brisk

Stirring to life with a bass-laden burble brimming with a sense of languid potential, the DB11 Volants’s prodigious Mercedes-AMG sourced twin-turbocharged direct injection 4-litre V8 engine is, however, highly responsive from standstill, owing to its use of two twin-scroll turbos on a “hot-V” position. Located between the two cylinder banks, the turbos’ short gasflow paths help much reduce turbo lag. With its engine note hardening to a thumping mid-range staccato before full-throated wail at top end, the DB11’s engine is responsive and eager rips through to a 7,200rpm rev limit. Vicious and relentless when prodded, it remains refined and smooth when driven forgivingly.

Tuned to produce 503BHP at 6,000rpm, the Volante’s engine also receives an additional 15lb/ft
torque over the fixed-head coupe model, for a total 513lb/ft achieved throughout a broad and seemingly ever accessible 2000-5,000rpm. Digging its huge 295/35ZR20 rear tyres into the ground, the Volante is thoroughly quick, with 0-100km/h arriving in 4.1-seconds and 0-200km/h in 8.8-seconds before continuing to a 300km/h top speed. Effortlessly capable of shifting the Volante’s hefty 1,870kg mass, its engine is mated to a smooth and swift-shifting 8-speed automatic gearbox (rather than Mercedes’ 9-speed) with manual mode paddle shifters to best harness its potential for performance and efficiency.

Fluent and flat

Riding on double wishbone front and multi-link rear suspension with adaptive Skyhook damping, the DB11 can be set in several and escalating driving modes which increase suspension stiffness levels, throttle response and steering weighting. Driving in its most forgiving default mode, the Volante’s ride was expectedly firm over jagged cracks and bumps at low speed, owing to its huge 20-inch low profile tyres. However, once it picks up speed, and through flowing, textured and snaking country lanes, the Volante’s ride becomes surprisingly supple and fluent over punishing vertical imperfections, where its added body stiffening seems to well compensate for the reduced of rigidity associated with convertible cars.

Taut and well containing cornering body roll even in its most comfortable setting, the Volante is eager into corners and agile throughout, and benefits from a limited slip rear differential which apportions power to the driven wheel that can best translate it into traction and forward motion. Meanwhile, a torque vectoring system uses light selective wheel braking to improve agility, manoeuvrability and stability through corners. A noticeably wide car at first when driving through narrow residential roads, one, however, soon develops an instinct for the Volante’s proportions, and once on open country lanes, it feels like a considerably lighter and smaller car.

Sophisticated and settled

Settled on rebound and over crests and dips through switchbacks and B-roads, the DB11 Volante is also reassuringly stable at speed, with little wind buffeting and good heating system allowing for cold weather top down driving. However, at the first sign of a drizzle, the Volante’s well-insulated electrically-operated 8-layer fabric roof raises in just 16-seconds to provide a more refined cabin ambiance. A more compact mechanism, the DB11’s roof frees up more boot room than its DB9 predecessor. However, this is a relative comparison, for while the DB11 Volante’s boot will accommodate weekend luggage for two, it is not exactly generous in absolute terms.

With its Mercedes-AMG engine, and other tri-star electronic components including its infotainment system, the DB11 has a distinct sense of familiarity for regular Mercedes drivers. Its steering had a similar feel and weighting on centre, but was, however, more alert and eager through corners. Regardless, the DB11 has its own distinct and elegantly upmarket sense of ambiance and occasion, with rich two-tone blue and cream leather, quality wood and metal accents, including front seat backs. Thoroughly well equipped with convenience and safety features, the Volante also proved to be unexpectedly practical, with its rear seats accommodating average sized adults.

TECHNICAL SPECIFICATIONS

• Engine: 4-litre, twin-turbocharged V8-cylinders
• Bore x stroke: 83 x 92mm
• Compression ratio: 10.5:1
• Valve-train: 32-valve, DOHC, direct injection
• Gearbox: 8-speed automatic, rear-wheel-drive, limited-slip differential
• Final drive: 2.703:1
• Power, BHP (PS) [kW]: 503 (510) [375] @6000rpm
• Specific power: 126.3BHP/litre
• Power-to-weight: 269BHP/tonne
• Torque, lb/ft (Nm): 513 (695) @2000-5000rpm
• Rev limit: 7,200rpm
• 0-100km/h: 4.1-seconds
• 0-200km/h: 8.8-seconds
• Top speed: 300km/h
• CO2 emissions, combined: 253g/km
• Fuel capacity: 78-litres
• Length: 4,750mm
• Width: 1,950mm
• Height: 1,300mm
• Wheelbase: 2,805mm
• Unladen weight: 1,870kg
• Weight distribution, F/R: 47 per cent/53 per cent
• Steering: Electric-assisted rack & pinion
• Lock-to-lock: 2.4-turns
• Suspension: Double wishbones/multi-link, adaptive dampers
• Brakes, F/R: Ventilated discs 400x36mm/360 x 32mm
• Brake callipers, F/R: 6-/4-piston callipers
• Tyres, F/R: 255/40ZR20/295/35ZR20
• Price: JD192,000 (exclusive of Jordanian taxes and duties)

By Marian Podoleanu

Health and Fitness Educator

We know that exercise makes us healthier and helps us lose weight, prevent injuries and build strength, but what effect does exercise have on our brains?

This year, let’s get “brainy” about our self-care so that we can plan, focus and process better for personal and professional success. Get your family engaged in an endurance sport like running, cycling, jogging, dancing, frisbee — any form of aerobic movement you enjoy for at least three times a week with an intensity that gets you sweating. Remember the benefits are for all ages! And take up yoga to learn how to breathe and practise it every morning before heading to work.

Most of us live in our minds, yet, very little housekeeping, maintenance or improvement is done for our brains. Cell biologist Bruce Spielgeman and his colleagues isolated the FNDC5 hormone and called it IRISIN after Iris, the Greek messenger goddess. Spiegelman foresaw the role of IRISIN as a ‘messenger’: “Exercise ‘talks to’ various tissues in the body.” 

Benefits of aerobic exercises

Studies on people ranging in age from four to 79 prove that aerobic activity in moderation and sustained for enough time to produce a sweat stimulates the muscle cells to produce IRISIN. This hormone is believed to stimulate the hippocampus, which plays an important role in helping our cognitive, memory and information processing capabilities. Stimulating IRISIN generation through sustained aerobic exercise: 

Helps maintain a healthy weight

Stimulates the growth of neurons and improves cognition

May slow the ageing process

Oxygen and water are well-being catalysts we cannot do without. The brain performs at its best when well hydrated and when the body captures enough oxygen to support the brain’s metabolic function. In practice, I have met very few people that know how to breathe. It is a practice we excelled at as kids but forgot as we grew older.

Remember that in order to succeed in life and give more of yourself to your family, company, friends and yourself, you must become more able, more focused and better planned to unleash the creative spirit within you. Have a fantastic 2018!

Reprinted with permission from Family Flavours magazine

PARIS — Women who shun fruit or eat lots of fast food take longer to get pregnant and are less likely to conceive within a year, according to a study released Thursday.

A nearly no-fruit diet compared to one loaded with three or more pieces per day added about two weeks, on average, to the time of conception, researchers reported in the peer-reviewed journal Human Reproduction.

And women who consumed fast foods such as burgers, pizza and deep-fried chicken four or more times a week compared to those who never or rarely touched the stuff took an extra month to become pregnant.

“These findings show that eating a good quality diet that includes fruits and minimising fast food consumption improves fertility and reduces the time it takes to get pregnant,” said lead researcher Claire Robers, a professor at the University of Adelaide in Australia.

Earlier research on food and pregnancy has focused mostly on the diet of women diagnosed with, or receiving treatment for, infertility. The impact of maternal diet before conception among women more generally has received scant scientific attention.

To help fill that gap, Roberts and a dozen colleagues in Australia, Britain and New Zealand combed through data gathered through questionnaires by midwives between 2004 and 2011 in all three countries for the Screening for Pregnancy Endpoints (SCOPE) survey.

Detailed answers given by nearly 5,600 women in the early phase of pregnancy focused on what they ate in the months preceding conception.

All of the women were first-time mothers, and only a relative handful — 340 — had received any kind of fertility treatment before becoming pregnant.

The results showed a clear link between the avoidance of fruits or a fondness for fast-food fare, on the one hand, and a longer “time-to-pregnancy” or higher risk of infertility, on the other.

At the extremes, for example, lots of fast food as opposed to none at all increased the risk of not becoming pregnant by 41 per cent.

The results were adjusted to take into account the potentially adverse impact on fertility of advanced maternal age, obesity, smoking and alcohol consumption.