Dietician

Dietician .net

Obesity can be caused by a virus and can be caught like the common cold, say researchers at the Pennington Biomedical Research Center in Louisiana. The highly-infectious virus, an adenovirus called AD-36, can be caught as easily as a cold from the coughs, sneezes and hands of those infected.

Once caught, the virus circulates through the body causing runny noses and sore throats. It also causes fat cells to multiply and can lead to massive weight gain.

“This virus goes to the lungs and spreads through the body,” said Nikhil Dhurandhar, an associate professor at the Pennington Biomedical Research Center in Baton Rouge, Louisiana. “It goes to various organs and tissues such as the liver, kidney, brain and fat tissue,” Dhurandhar told BBC2’s “Horizon” program.

“When this virus goes to fat tissue it replicates, making more copies of itself and in the process increases the number of new fat cells, which may explain why the fat tissue expands and why people get fat when they are infected with this virus.”

Victims of the virus could remain infectious up to three months.

Studies show that 33 percent of all obese adults have the AD-36 virus compared to only 11 percent of thinner people. Tests in animals infected with the virus gained weight more quickly than those animals not infected even when they did not eat more.

Regardless of the virus’ role in causing obesity, most scientists agree that the single largest cause of obesity is eating too many and too much of the wrong foods.

Cutting calories could do more than just slim down your waistline.

Researchers from the University of Munster in Germany found reducing what you eat by a third may improve memory, the BBC reported Tuesday.

They analyzed three groups of volunteers on different diets, who had an average age of 60.

Three months later, they were given memory tests.

The first group ate a balanced diet containing the normal number of calories, while the second group consumed a similar diet, but with a higher proportion of unsaturated fatty acids.

The final group was put on a calorie restricted diet.

After the three months, there was no difference in memory scores in the first two groups, but the 50 volunteers in the third group performed better.

The third group also had decreased levels of insulin and fewer signs of inflammation, according to the report.

The researchers said that these changes could explain the better memory scores, by keeping brain cells in better health.

The study is reported in the Proceedings of the National Academy of Sciences journal.

More at the BBC.

Studies find mercury in much U.S. corn syrup

WASHINGTON (Reutersc) – Many common foods made using commercial high fructose corn syrup contain mercury as well, researchers reported on Tuesday, while another study suggested the corn syrup itself is contaminated.

Food processors and the corn syrup industry group attacked the findings as flawed and outdated, but the researchers said it was important for people to know about any potential sources of the toxic metal in their food.

In one study, published in the journal Environmental Health, former Food and Drug Administration scientist Renee Dufault and colleagues tested 20 samples of high fructose corn syrup and found detectable mercury in nine of the 20 samples.

Dufault said in a statement that she told the FDA about her findings but the agency did not follow up.

Dr. David Wallinga, a food safety researcher and activist at the nonprofit Institute for Agriculture and Trade Policy, said he followed up on the report to find mercury in actual food.

“When I learned of that work, I said that is interesting but we don’t just go out and eat a spoonful of high fructose corn syrup,” Wallinga said in a telephone interview.

“We went and looked at supermarket samples where high fructose corn syrup was the first or second ingredient on the label,” he said. These 55 different foods included barbecue sauce, jam, yogurt and chocolate syrup.

“We found about one out of three had mercury above the detection limit,” Wallinga said.

The Corn Refiners Association challenged the findings.

“This study appears to be based on outdated information of dubious significance,” the group said in a statement.

Wallinga and colleagues said they believed the mercury got into the food during manufacture, at plants that use mercury-grade caustic soda produced in industrial chlorine plants, although his team was unable to show this.

“Our industry has used mercury-free versions of the two reagents mentioned in the study, hydrochloric acid and caustic soda, for several years,” Audrae Erickson, president of the Corn Refiners Association, said in a statement.

Wallinga said the studies were based on samples taken in 2005, the most recent available.

Many studies have shown that fish can be high in mercury. Wallinga said consumers should know about other potential sources so they can limit how much they eat. “The best mercury exposure is no exposure at all,” he said.

“Even at low levels methylmercury can harm the developing brain. The last thing we should intentionally do is add to it,” Wallinga added.

He said his team did not test foods that did not contain corn syrup to see if they were also high in mercury.

Trevose, PA (January 27, 2009) –  Rita’s, the nation’s largest Italian
Ice concept with more than 550 stores, today announced the debut of its new
“Light Line” menu, a comprehensive offering of healthier frozen treat
options.  Rita’s “Light Line” menu items include Sugar-Free Italian Ice
and Slenderita, a creamy and delicious fat-free soft serve.

Rita’s has introduced the following three Sugar-Free Italian Ice flavors this
year: Mango Peach, Chocolate and Pineapple. These flavors will join Rita’s
existing Sugar-Free lineup of Tangerine, Cherry, Pink Lemonade and Root Beer,
for a total of 7 Sugar-Free Italian Ice flavor offerings.  Rita’s Slenderita
is available in Vanilla at participating locations.

To ensure that more Guests are able to enjoy Rita’s delicious treats, the
company has launched the new line to offer healthy treat options for those with
dietary restrictions or watching their waistline. Rita’s believes that the
current offerings, coupled with the new healthier treats, will bring Guests
coming back for more while attracting new Guests who are looking for healthier
treat alternatives.

“The feedback we get from our valued Guests is highly instrumental in our
menu construction,” said Jim Rudolph, Chairman of the Board and Chief
Executive Officer, Rita’s Franchise Company. “Many Guests have special
dietary needs and concerns, and our new ‘Light Line’ allows them the
opportunity to enjoy our legendary frozen treats. We will continue to innovate
and develop products for our Light Line throughout 2009 and beyond.”

Rita’s “Light Line” selections are currently available at Rita’s
locations.  For more information on Rita’s “Light Line,” and for
nutritional information on all Rita’s products, please visit www.ritasice.com
<http://www.ritasice.com> .

A Philadelphia tradition, Rita’s Italian Ices are made fresh daily and are
available in more than 40 different flavors.  Rita’s Old-Fashioned Frozen
Custard is a soft serve dessert that is available in chocolate, vanilla,
strawberry and coffee flavors and can be served in a cup or a cone. Rita’s
Gelati is a delightful frozen treat that provides the best of both worlds –
frozen custard mixed with layers of Italian Ice.  Similar to the Gelati,
Rita’s Misto Shake is also a blend of Italian Ice and frozen custard and is a
convenient treat for those on the go. Rita’s Blendini is a blend of Rita’s
frozen custard, fresh Italian Ice and crushed OreoÒ cookie pieces or NillaÒ
wafer pieces.  Rita’s SlenderitaTM is a creamy and delicious Fat-Free soft
serve that is available in vanilla and can be served in a cup or a cone, in
Gelati, or blended into a BlendiniTM.  Rita’s first-ever coffee drink, The
RitaccinoTM, is a frosty treat with a rich coffee taste, topped with Rita’s
famous vanilla custard.  Rita’s also offers Sugar-Free Italian Ice in Cherry,
Pink Lemonade, Root Beer and Tangerine, Mango Peach, Chocolate and Pineapple.

About Rita’s
Rita’s Franchise Company, headquartered in Trevose, Pa., is the largest
Italian Ice concept in the nation, currently operating in 17 states with more
than 550 stores. Rita’s brand promise is Ice, Custard and Happinessä. The
chain offers a variety of frozen treats including its famous Italian Ice, Old
Fashioned Frozen Custard, and layered Gelati, as well as its signature Mistoä
and Blendiniä creations. Rita’s was named one of the Top 25 Franchise High
Performers by the Wall Street Journal’s ‘Startup Journal.’ For more
information about Rita’s, please call 1-800-677-RITA or visit www.ritasice.com
<http://www.ritasice.com>

Got Fat?

While the acronym MUFA does not sound too appealing, the MUFA diet and MUFA foods are popular diet trends for the New Year and beyond. MUFA is not a fad and it’s not unhealthy. A MUFA diet incorporates certain types of foods, namely fats, into a healthy and nutritious diet. The MUFA diet is not a meal replacement diet, nor does it require any special supplements or products you order in the mail. The MUFA diet recognizes that eliminating foods with fat from a diet is not the best way to lose weight. It’s not about the fat, it’s about the right type of fat.Eating low fat foods has not made a large impact on weight loss in the country, according to the Harvard School of Public Health. The total amount of fat in the diet is not as important as the type of fat in the diet, Harvard reports.

What is MUFA?

MUFA stands for monounsaturated fatty acids. Monounsaturated fatty acids are labeled as “good fats” by health experts including the American Diabetes Association and the American Heart Association. Good fats are beneficial cholesterol levels.

Identifying MUFA Foods

Identifying MUFA foods is not difficult. MUFA foods tend to fall into certain food group categories including nuts, seeds and oils made from vegetables, according to the Harvard School of Public Health. Focus on natural, not processed foods which do not contain trans fat, saturated fat or animal-based fat. Check nutrition labels or use an online nutrition guide to find foods which contain unsaturated fat. Unsaturated fats include Monounsaturated fats and polyunsaturated fats.

MUFA Foods:

• Oils One type of MUFA food is cooking oils, including Canola oil, Olive oil and Sunflower oil. Less popular, but healthy is grape seed oil, a light oil which raises good cholesterol levels. Walnut oil, flax seed oil and soybean oil are also considered MUFA foods.

• Nuts and seeds including almonds, macadamia nuts, peanutsButter forms of these nuts and seeds, especially when they are not made with added sugars are also MUFA foods. Try almond butter, cashew butter or sunflower butter instead of the regular peanut butter. For snacking or for cooking, try Brazil nuts, sunflower seeds, hazelnuts, pine nuts, pecans and walnuts.

• Avocados and olives are also considered MUFA foods. Make an avocado dip for your broiled chicken dish or add olives to your recipes.
• Dark Chocolate Finally, the food you’ve been waiting for: dark chocolate is considered a MUFA food. Use in moderation.

Caveat About MUFA Foods

MUFA foods may be part of an overall healthy diet that can help dieters lose pounds, but the should still be eaten in moderation. These foods are not the lowest calorie foods available to dieters. The list of MUFA foods is short. Dieters following a MUFA diet and incorporating MUFA foods into their diet can print out this short list.

Which Diets Incorporate MUFA Foods?

The Flat Belly Diet, by Prevention, incorporates MUFAs, Sassy water and other healthy foods in the diet plan. The Mediterranean Diet, which includes canola oil, olive oil and nuts also has MUFA diet elements.  Any diet or way of eating can be modified to include MUFA foods. Eiminate bad fat, replace it with good fat, and exercise more.

Sources

• American Diabetes Association, http://www.diabetes.org/diabetes-cholesterol/faqs-fat.jsp
• American Heart Association, http://www.americanheart.org/presenter.jhtml?identifier=4582
• Harvard School of Public Health, http://www.hsph.harvard.edu/nutritionsource/what-should-you-eat/fats-full-story/index.html

More resources

Increase in Death Risk Not Limited to Overweight, Obese

Belly fat has been linked to an increased risk of heart disease and diabetes. Now an important new study links belly fat to early death.

Researchers followed about 360,000 Europeans enrolled in one of the largest, longest health studies in the world.

They found that people with the most belly fat had about double the risk of dying prematurely as people with the least amount of belly fat.

Death risk increased with waist circumference, whether the participants were overweight or not.

The study provides some of the strongest evidence yet linking belly fat to early death, says lead author Tobias Pischon, MD, MPH. It appears in the Nov. 12 issue of TheNew EnglandJournal of Medicine.

“Our study shows that accumulating excess fat around your middle can put your health at risk even if your weight is normal,” he says. “There aren’t many simple individual characteristics that can increase a person’s risk of premature death to this extent, independent of smoking and drinking.”
Belly Fat Research

It has long been recognized that people who carry their excess weight around their middles — those who are apple-shaped instead of pear-shaped — have a higher risk for heart attacks and strokes.

Recent research also suggests a link between belly fat and a range of other diseases, including diabetes, some cancers, and even age-related dementias.

But it has not been clear whether the increase in death risk associated with abdominal obesity occurs independently of recognized risk factors like general obesity, Pischon says.

The researchers used two measures of abdominal obesity — waist circumference and waist-to-hip ratio — in their attempt to better understand the role of belly fat in early death.

They examined data on 359,387 European adults followed for nearly 10 years who were enrolled in the larger, ongoing European Prospective Investigation into Cancer and Nutrition (EPIC) health study.

During the follow-up period, 14,723 of the study participants died.

After adjusting for overweight and obesity, as measured by body mass index (BMI), waist circumference and waist-to-hip measurements were both independently associated with an increased risk for early death.

Specifically:

* Men and women with the largest waists (more than 40 inches for men and 35 inches for women) had roughly double the risk of premature death as men and women with the smallest waists (less than 34 inches for men and 28 for women).
* Each 2-inch increase in waist circumference was associated with close to a 17% increase in mortality in men and a 13% increase in women.
* Waist-to-hip ratio also strongly predicted mortality.

“The most important result of our study is the finding that not just being overweight, but also the distribution of body fat, affects the risk of premature death,” Pischon says.

The findings come as no surprise to University of Michigan cardiologist and research scientist Daniel Eitzman, MD.

Work by Eitzman and colleagues in mice found that belly fat — also known as visceral fat — produces more inflammation than fat found in other areas of the body.

Inflammation is thought to play a key role in heart disease and a host of other chronic diseases.

Eitzman tells WebMD that measurement of waist circumference or waist-to-hip ratio are important for assessing the risk of inflammation-driven disease.

“Studies like this focus attention on the importance of measuring visceral fat, which is not now routinely done in clinical practice,” he says.
Are You an Apple or a Pear?

So how do you tell if you have more belly fat than is healthy?

* To measure your waist circumference, place a tape measure around your waist at the smallest point, which is usually just above the navel. A waist size of 40 inches in men and 35 inches in women is generally considered to indicate increased health risk.
* Waist-to-hip ratio is calculated by measuring your waist at the smallest point and your hips at the widest point — usually at the widest part of the buttocks — and dividing the waist measurement by the hip measurement. A waist-to-hip ratio of greater than 0.9 for men and 0.8 for women is generally considered high risk.

Source: WebMD

Obese Kids Have Middle-Aged Arteries
Scientists have found accelerated evidence of heart disease among obese children and teens.

A glimpse inside the neck arteries of obese children and teens reveals cardiovascular systems more like those of 45-year-olds, researchers said Tuesday.

Scientists using ultrasound imaging detected fatty deposits more typical in middle-aged adults than in children as young as 10, underscoring worries about accelerated risks of heart disease decades earlier than once thought possible.

“There’s a saying that you’re as old as your arteries,” said the study’s lead author, Dr. Geetha Raghuveer, associate professor of pediatrics at the University of Missouri Kansas City School of Medicine. “These kids are showing up with arteries that show middle-aged conditions.”

In fact, more than half of the 70 youngsters enrolled in the Children’s Mercy Hospital study had a “vascular age” about 30 years older than their actual age, putting them at risk for early heart attacks, stroke — and death. The research was presented Tuesday at the American Heart Association’s scientific meeting in New Orleans.

That finding might also hold true for many more young people in the United States, where more than 16 percent of kids ages 2 to 19 are considered obese, according to federal statistics.

“It kind of hammers home that the risk might be speeded up,” said Dr. Stephen Daniels, chief pediatrician at the Children’s Hospital in Denver, who was not associated with the new study. “It does kind of fit with the concept that kids with high cholesterol and other risk factors probably have premature aging factors.”

This isn’t the first time aging arteries have been documented in kids. Previous studies have reported that growing numbers of children with risk factors for heart disease are showing signs of narrowing and hardening of the arteries, conditions typically associated with adults.

But Raghuveer and her colleagues used ultrasound imaging to measure the thickness of the inner walls of the carotid arteries that supply blood to the brain. Increasing carotid artery intima-media thickness, or CIMT, indicates a build-up of fatty deposits, known as plaque, in crucial arteries to the heart and brain. Plaque build-up in the arteries, which is usually affects adults, can restrict the flow of blood, causing heart attacks or stroke.

Then they plotted the measurements on a graph for adult plaque levels — because similar measures don’t exist for kids.

The small study included children ages 6 to 19, but most were ages 10 to 18 and the average age was 13, Raghuveer said.

The children’s average CIMT was .45 millimeters, with a maximum of .75 millimeters. One 12-year-old boy logged a CIMT of .54, which placed him smack in the middle of measurements expected to be seen in a healthy 45-year-old man — .50 millimeters to .57 millimeters.

“If I see a kid with a .54 plaque in his carotid artery, a 12-year-old kid, I’m going to be concerned,” Raghuveer said.

Youngsters most at risk in the study were those who were obese, with body mass index or BMI at or above the 95th percentile, and those who had abnormally high cholesterol levels, including either too much of the so-called “bad” LDL cholesterol, or too little of the “good” HDL cholesterol.

In addition, some children and teens had levels of fat chemicals known as triglycerides far above optimum levels.

‘It was just alarming’

That group included Nick Calvert, a 17-year-old high school junior from Kansas City, Mo. His triglycerides topped out at more than 500 milligrams per deciliter, nearly triple the recommended 150 mg/dl that is considered acceptable.

“Well, it was very upsetting,” said Nick’s mother, Lisa Calvert, 41, a homemaker and mother of three who long ago stopped cooking with butter. “It was just alarming. I felt like I needed to sit down and talk to him.”

Nick was stocky, but not obese, weighing at 182 pounds on a 5-foot-9 frame. But he’s been struggling with genetically high cholesterol levels since he was 2, and a typical teen diet didn’t help.

“I’d go out with my friends and they’d eat and I’d eat, too,” said Nick, who acknowledged a fondness for burgers and pop.

When the ultrasound also detected thickening in his carotid arteries, Nick and his family got scared. He signed up with a personal trainer and started watching his diet, swapping burgers for grilled chicken and soda for water and tea.

“If I don’t do it, I could have a heart attack or stroke at a younger age,” said Nick, who has lost 20 pounds in the past few months, dropping him to 162 pounds.

That kind of proactive attitude is vital, said Dr. Samuel S. Gidding, chief of pediatric cardiology at the Alfred I. duPont Hospital for Children in Wilmington, Del.

Children and teens don’t typically suffer heart attacks, but they can be at risk for early signs of heart disease, said Gidding. He noted that Raghuveer’s work confirms previous autopsy studies that showed a strong link between budding heart disease and risk factors in young people.

Changing diet and increasing exercise can slow and perhaps stop deterioration, he said. Although the American Academy of Pediatrics recently recommended cholesterol-lowering drugs for kids as young as 8, Gidding said he’s waiting to release new guidelines through the National Heart, Lung and Blood Institute, NHLBI, next year.

In the meantime, the new research is a reminder to take steps to prevent obesity and high cholesterol before children’s arteries grow older than their years, Raghuveer said.

“I’m very hopeful we can reverse this process,” she said.

Olympic swimmer Michael Phelps may have an appetite for gold, but he has a bigger appetite for food.

“They say he took in 10,000 to 12,000 calories a day,” said St. Mary’s dietician Tammy Fumousa.

Phelps’ typical breakfast is three fried egg sandwiches with cheese, lettuce, tomatoes, fried onions and mayo, one five-egg omelet, a bowl of grits, three slices of French toast with powdered sugar, three chocolate chip pancakes and energy drinks.  “The normal individual needs about 2,000 calories (a day) if they’re active,” said Fumousa.

But Phelps is anything by normal.”He needs that many calories,” said Fumousa. Phelps’ workouts are grueling.

Michael Phelps Diet - Mayo

“Michael Phelps, I know for a fact that he puts in a lot of yardage,” said swim coach Jason Verhelst. Verhelst coaches Madison Memorial’s swim team and he swam for the Badgers while in college.  He said no matter what the level of competitive swimming, the advice is the same. “They have to eat,” he said.  “You have to be able to replace the calories. You can’t skip a meal.

“Phelps isn’t exactly chowing down on vegetables. “He’s not really eating Ho Ho’s and Twinkies,” said Fumousa. “He’s eating protein. He’s eating carbohydrates.

“The mayonnaise Phelps eats actually helps absorb the nutrients in his body. “He has to add all this other stuff like the mayo to his sandwiches to give it a little fat,” said Fumousa.

The only change Fumousa said she would make to Phelps’ diet would be to exchange some of the calories for fruits.

Michael Phelps diet is making me fat

Dear Cuckoo,
I’m surprised you don’t have ripped stretchmarks. Write back after you’ve worked out along side the human dolphin for a month.
Abby

Phelps, 23, will swim 17 times over nine days of competition at the Beijing Games – meaning that he will need all the calories he can shovel in his mouth in order to keep his energy levels high.

Phelps’ diet – which involves ingesting 4,000 calories every time he sits down for a meal – resembles that of a reckless overeater rather than an Olympian.

Phelps lends a new spin to the phrase “Breakfast of Champions” by starting off his day by eating three fried-egg sandwiches loaded with cheese, lettuce, tomatoes, fried onions and mayonnaise.

He follows that up with two cups of coffee, a five-egg omelet, a bowl of grits, three slices of French toast topped with powdered sugar and three chocolate-chip pancakes.

At lunch, Phelps gobbles up a pound of enriched pasta and two large ham and cheese sandwiches slathered with mayo on white bread – capping off the meal by chugging about 1,000 calories worth of energy drinks.

For dinner, Phelps really loads up on the carbs – what he needs to give him plenty of energy for his five-hours-a-day, six-days-a-week regimen – with a pound of pasta and an entire pizza.

He washes all that down with another 1,000 calories worth of energy drinks.

A story from across the pond…

Alternate-day fasting is the latest diet craze. But is it good for your waistline or your health? Our expert investigates

News that detoxing is potentially dangerous will have caused ripples of panic among those who rely on it for inner cleansing and occasional inch loss. Dawn Page, a 52-year-old mother of two from Oxfordshire, made headlines when she received more than £800,000 after suffering permanent brain damage while on a detox diet that instructed her to reduce her salt intake and consume large amounts of water.

Long before this case, reputable dieticians were questioning the effectiveness and safety of detoxing. A detox diet can last anything from 48 hours to 21 days, and most involve drinking two litres or more of water a day, along with dandelion coffee and herb teas that are thought to help expel environmental nasties. Most also recommend additional fluids – carrot and apple juice are favourites because of their “digestion boosting” properties – and some allow unlimited consumption of raw fruit and vegetables, but little else. Catherine Collins, chief dietician at St George’s Hospital in London, says she has seen dozens of people with debilitating detox side effects, usually as a result of consuming more water and less salty food, often in conjunction with increased activity.

One was a 23-year-old patient who had slipped into a four-day coma as a result of hyponatraemia (water intoxication, which causes blood sodium levels to plummet and the brain to swell) induced by a three-week detox diet. Too much fluid and too little dietary sodium mean body salts, or electrolytes, in the blood become dangerously diluted. “Sticking to a detox regimen for a day or two won’t be harmful for most people – neither will it have any effect on their long-term health – as there is no scientific basis for it,” Collins says. “But when detox plans promote longer periods of severe dietary restriction, which many do, they can cause problems.”

So, with detox phobia rife, is there a more moderate and less risky alternative? Some scientists think so and are advocating an approach called alternate-day fasting (ADF), which should appeal to those who have trouble sticking to a harsh dietary regimen in the first place. For most of us, diets are a calorie seesaw: you cut down your intake with grim determination one day, only to be ravenously hungry the next. And, according to the scientists who have studied ADF, this may be no bad thing. Their admittedly controversial research has shown that restricting calories for 24 hours and reintroducing them the following day will not only help you to shift pounds and fat cells, but also to live longer.

A quick internet search reveals there are hundreds of visitors to ADF and “intermittent-fasting” chat rooms, along with thousands of sites detailing the purported benefits of this bizarre trend for self-imposed semi-starvation. In America, a raft of books on the subject, such as The Alternate-Day Diet and The QOD Diet: Eating Well Every Other Day, have further raised its profile and appeal. “Alternate-day fasting lets you focus your hunger in manageable periods,” says Brian Delaney, author of The Longevity Diet. “You are not a little hungry all the time, like you are on a normal diet, but you are very hungry for a little time.” And with a growing body of scientific backing for its health benefits, AFD is, potentially, more than just another diet fad.

Recently, nutritionists at the University of California found that eating half as much as usual every other day could shrink fat cells and boost some of the mechanisms that break down fat. Krista Varady and her team put some mice on a full alternate-day fast, while others were allowed to eat half as much as usual on their fasting days. The results showed that, while the first group lost more weight, the fat cells of all the dieting mice shrank by at least 35%. Another study, published three years ago in the American Journal of Clinical Nutrition, showed that people who followed the ADF diet for just three weeks lost an average 2.5% of their body weight and 4% of their body fat.

Even if you fast one day, then are so chew-off-your-arm hungry the next that you gorge on highly calorific goodies, there seem to be health benefits. In a study carried out at the National Institute on Ageing, American scientists allowed mice to eat nothing one day and trained them to tuck into as much food as they wanted during the next 24 hours. Although they were too greedy on their eating days to shed weight, they still had improved insulin sensitivity – meaning they cleared sugar from the bloodstream more efficiently, a vital factor in preventing diabetes – and a longer life span than the mice who ate regular meals every day.

So, how does ADF work? Like our hunter-gatherer ancestors, who spent days searching for food and ate only intermittently, we are genetically programmed to adapt to cycles of fasting and feasting. Scientists say the temporary withdrawal of food for short periods appears to stress the body in a positive way, so that a gene called Sirt1 is switched on. This gene is also activated by resveratrol, the antioxidant present in red grapes and wine that is known to ward off heart disease and help the body to use fats in the bloodstream for energy.

Not all nutritionists think ADF is the way to go, however. Some argue that it is impossible to stick to long term. In the few human studies carried out on ADF, subjects have often reported feeling tired, tetchy and hungry on the days they were required to fast. Critics suggest that those looking to lose weight do not need to subject themselves to such a harsh regimen. They point to a study by researchers at Cornell University that showed that simply restricting calories for one meal a day could help to shift pounds. When a group of people were asked to cut their usual lunch to 200 calories, they didn’t compensate by eating more during the rest of the day.

Those who try ADF should bear in mind that food must be ultra-healthy, as “with no calories to spare, every bite you take needs to be packed with nutrition”, says Susan Bowerman, assistant director of the Center for Human Nutrition at the University of California, who has reviewed the trend. “There is a lot of research to be done before the animal studies that have proven it to be healthy are replicated in humans,” says Lisa Miles, a nutrition scientist at the British Nutrition Foundation. “If you have overeaten one day, then it will help to balance out your calorie intake by eating less the next, but it is not something that we would recommend on a long-term basis.”

Detox fads: the big three

• Master Cleanse: Also known as the Maple Syrup Diet or the Lemon Detox, it involves drinking glasses of Madal Bal natural tree syrup mixed with lemon juice and cayenne pepper — see The Complete Master Cleanse by Tom Woloshyn (Ulysses £6.99). During the recommended 10-day fast, it is suggested that no food is consumed. Beyoncé reportedly lost 22lb on this.

  Verdict: Contains too few nutrients and might be dangerous.

• 21-day detox: Oprah Winfrey tried it recently. Devised by Kathy Feston — it featured in her American bestseller Quantum Wellness (Weinstein £12.70) — it advocates adopting a vegan diet of whole grains, beans and legumes, and steamed or sautéed vegetables for three weeks.

  Verdict: Cutting out whole food groups, such as meat, can leave you prone to serious nutritional deficiencies.

• The Longevity Diet (Four Walls Eight Windows £6.99): the author, Brian Delaney, is president of the Calorie Restriction Society, a group that practises what they preach. This regimen has been shown to increase life expectancy in animals.

  Verdict: Too strict — followers are allowed to consume only 1,200 calories a day.

My week of hunger

There comes a time every summer when you wish you had started on that bikini diet a little earlier. Two weeks ago, that time struck me. So, in a blind panic at the thought of baring my unprepared body by the pool, I embarked on a detox. The General Motors Diet — so called because it was invented for the overweight employees of the American car manufacturer — promises to help you shed 10lb-17lb in a week. Perfect, I thought.

It is marginally easier to follow than some other detoxes, in that each day is different. So, it’s fruit only on day one (but you can eat as much as you like), veg on day two, fruit and veg on day three, bananas and milk on day four (odd, yes), beef and tomatoes on day five (even odder), leading you to the end of the week, when you start to eat things that actually resemble meals. And there’s no sugar or alcohol.

The rules are simple, but sticking to them? Harder. I started off the week with gusto, keenly munching on copious amounts of melon, and cancelling all plans in favour of a camomile tea in front of the telly. But by day three, I caved in — felled by a vodka and tonic — and it was all downhill from there. I discovered that, if you have a normal job and social life, you can forget about doing them and a detox at the same time. Not only do you feel faint, hungry and listless — you also feel stifled, bored and boring. Much like the diet itself. So it’s sarongs and kaftans again for me this year.