Fad diets can work, but experts find no magic slimming bullet

January 13, 2014

Resolutions to lose weight are often made in January yet almost as frequently abandoned as heavy hopefuls find diets that demand fasting, virtually no carbs or liquid food shakes notoriously hard to stick to. But even "fad" diets can lead to a slimmer, lighter New Year for those whose resolve remains robust, according to doctors and nutritionists analysing them.

Gathering for a London conference to review evidence behind popular weight loss diets - at just the time of year when slimming ideas are in peak demand - specialists concluded that food fads such as the hunter-gatherer "Paleo" plan or the 5:2 diet can deliver. But it's hard work. "If it was easy, our species would have died out years ago. As humans we have a default to eat," said Gary Frost, a professor and chair of nutrition and dietetics at Imperial College London. The results of that default are looming large in a global "wave of obesity", he said. According to the World Health Organisation, worldwide obesity - defined as having a body mass index of more than 30 - has nearly doubled since 1980. The latest global figure is that in 2008, more than 1.4 billion adults were overweight.

WAVE OF OBESITY

According to the US Centers for Disease Control and Prevention, almost 36% of American adults are obese and almost 70% are either obese or overweight. In Britain, a government health study predicts 60% of men, 50% of women and 25% of children will be obese by 2050. Against this background, experts say the search for effective diets must always take account of how easy it is for people to understand and follow, and how likely they are to abide by its restrictions.

Michelle Harvie, a research dietician from the Genesis Prevention Centre at Britain's University Hospital of South Manchester, said that on this front, fasting diets - sometimes called intermittent diets - can be successful. "Energy restriction is difficult to maintain over the long term and people tend to find it easier to follow a diet with intermittent energy restriction," she said. She said that while a regular weight loss plan might require the dieter to take in 25% fewer calories, intermittent diets may suggest two days of a 75% calorie cut interspersed with five days of normal healthy eating. But the key to these diets - such as the 5:2 diet in which followers eat as little as 400 calories on two "fasting" days per week - is that dieters won't succeed if they "pig out" and eat whatever they want on non-fasting days.

Harvie's research shows those who succeed in losing weigh on these diets find the fasting days lead them to also have a lower food intake on normal days - leading to lower calorie intake overall.

HUNTING FOR FOOD

Mark Berry, head of plant biology and biochemistry at the consumer company Unilever's research and development unit, says there are also positive signs in data from studies of "Palaeolithic" or stone-age diets - plans designed to mimic the diet of pre-agricultural hunter-gatherers of that era. A sign of its current popularity is that "Paleo diet" was one of the most "Googled" terms of 2013.

The idea is based around foods that can be hunted, fished or foraged for - meat, seafood, eggs, nuts, seeds, fruits and vegetables. Berry said his research showed little impact on glucose response in the body in people eating a Palaeolithic diet, but did find a significant impact on hormones that signal satiety and tell the brain the eater is full. Alexandra Johnstone of the Rowett Institute of Nutrition and Health, who has been looking into high protein and low carbohydrate diets such as the Atkins diet, said these also had a significant impact on fullness feelings - giving them the potential to help dieters control appetite and lose weight. "The high satiety effects of increased protein in the diet seems to be a contributing factor to the success of high-protein, low-carbohydrate diets," she said.

Johnstone cited data showing the amount of weight lost on high-protein diets is around double that lost on a comparable low-fat diet at the six-month mark. But there is little difference in weight loss after one year, as dieters often lose momentum and their resolve to slim down fades. "There's no magic bullet," she said. Judy Buttriss, head of the British Nutrition Foundation, said the evidence for popular diets was clearly nuanced. While there are several that can be used as tools for effective weight loss and maintenance, she said "there's currently no evidence that one is any better than another in the long term".

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Agencies
March 16,2020

New Delhi, Mar 16: A recent survey across 140 districts of the country shows that about 54 per cent of Indians are finding travelling to be unsafe as the deadly coronavirus (COVID-19) pandemic sweeps globally.

The big worry that people have is community transmission, something that researchers from around the world have approximated at 10 per cent of total infections and more common in places like Wuhan in China, South Korea, Iran and Italy.

The months of March to June have historically been high travel season for most Indians, largely due to the summer vacations in schools. "But it seems that Indians do not want to take a chance with this rather scary virus and are either cancelling or postponing their travel plans," concluded the survey by LocalCircles.

The survey gathered more than 22,000 responses from participants in tier one, two and three cities. It said 48 per cent Indians plan to cancel their international business travel for the next four months.

Besides, nearly 38 per cent of respondents said they had to pay cancellation fee to the website, travel agent, airline or railways.

"These are testing times for the entire travel and tourism industry -- airlines, hotels, travel agents as well as small tour and taxi operators. The best solution at this point is to adjust cost structures, stay flexible and work with a collective approach to minimise the period of impact to both citizens and business," said LocalCircles.

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Agencies
June 29,2020

Washington DC, Jun 29: Young children with narrow retinal artery diameters were more likely to develop higher blood pressure, and children with higher blood pressure levels were more likely to develop retinal microvascular impairment during early childhood, according to a new study.

The first study to show this connection in children was published today in Hypertension, an American Heart Association journal.

High blood pressure, the main risk factor for the development of cardiovascular disease (CVD), can manifest as early as childhood, and the prevalence of high blood pressure among children continues to rise. In previous studies, analysis of blood vessels in the retina has shown promise as a predictor of CVD risk among adults. In the study titled, "Retinal Vessel Diameters and Blood Pressure Progression in Children," researchers sought to predict the development of high blood pressure in children over four years based on retinal blood vessel measurements.

"Hypertension continues as the main risk factor for the development of cardiovascular diseases and mortality," says Henner Hanssen, M.D., the study's lead author and a professor in the department of sport, exercise and health at the University of Basel in Switzerland. 

"Primary prevention strategies are needed to focus on screening retinal microvascular health and blood pressure in young children in order to identify those at increased risk of developing hypertension. The earlier we can provide treatment and implement lifestyle changes to reduce hypertension, the greater the benefit for these children."

Researchers screened 262 children ages six to eight from 26 schools in Basel, Switzerland, in 2014, for baseline blood pressure and retinal arterial measurements. Both measures were taken again in 2018. Blood pressure measurements at both baseline and follow-up were performed in a sitting position after a minimum of five minutes of rest and were categorized based on the American Academy of Pediatrics' blood pressure guidelines. These guidelines utilize the same measurements as the American Heart Association/American College of Cardiology 2017 Guideline for the Prevention, Detection, Evaluation, and Management of High Blood Pressure in Adults.

Results from the analysis indicate: children with narrower retinal vessel diameters at baseline developed higher systolic blood pressure at follow-up; retinal vessel diameters could explain 29 -31 per cent of the changes in systolic blood pressure progression between 2014 and 2018; children with higher blood pressure levels at baseline developed significantly narrower arteriolar diameters at follow-up, depending on weight and cardiorespiratory fitness; and initial blood pressure measures explained 66-69 per cent of the change in retinal arteriolar diameter from baseline to follow-up.

"Early childhood assessments of retinal microvascular health and blood pressure monitoring can improve cardiovascular risk classification. Timely primary prevention strategies for children at risk of developing hypertension could potentially counteract its growing burden among both children and adults," said Hanssen.

Researchers noted limitations of their study include that they could not confirm blood pressure measurements over a single 24-hour period, so they would not account for "white coat" hypertension, a condition where patients have high blood pressure readings when measured in a medical setting.

Developmental stage including puberty status of each child was not accounted for in the study, as well as genetic factors or birth weight - variables that could impact blood pressure development and microvascular health.

In addition, reference values for appropriate retinal vessel diameters in children do not currently exist, so future studies are needed to determine age-related normal values during childhood.

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Agencies
February 11,2020

Using smartphone for long hours every day may do you more harm than you can probably think of. Researchers have found that spending a lot of time with the device and on social media may lead to mental distress and suicidality among adolescents.

The findings, published in the journal CMAJ (Canadian Medical Association Journal) contains guidance for physicians, parents and teachers on how to help teenagers manage smartphone and social media use for a healthy balance between sleep, academic work, social activity, interpersonal relationships and online activity.

"Physicians, teachers and families need to work together with youth to decrease possible harmful effects of smartphones and social media on their relationships, sense of self, sleep, academic performance, and emotional well-being," said lead author of the study Elia Abi-Jaoude from Toronto Western Hospital in Canada.

This review of evidence, led by the Hospital for Sick Children (SickKids), focuses on smartphone use and does not consider online gaming.

"For adolescents today, who have not known a world without social media, digital interactions are the norm, and the potential benefits of online access to productive mental health information -- including media literacy, creativity, self-expression, sense of belonging and civic engagement -- as well as low barriers to resources such as crisis lines and Internet-based talking therapies cannot be discounted," the authors wrote.

The researchers recommend that doctors should ask teenagers to reduce social media use rather than eradicate it completely and encourage parents to be part of the conversations.

Parents should discuss appropriate smartphone use with teenagers to determine together how to reduce risks and set boundaries.

A recent poll from the US indicates that 54 per cent of teenagers think they spend too much time on their smartphones and about half said they were cutting back on usage.

"Encouragingly, youth are increasingly recognising the negative impact of social media on their lives and starting to take steps to mitigate it," the authors wrote.

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