October 26, New York Times, Gina Kolata
For years, studies of obesity have found that soon after fat people lost weight, their metabolism slowed and they experienced hormonal changes that increased their appetites. Scientists hypothesized that these biological changes could explain why most obese dieters quickly gained back much of what they had so painfully lost.
But now a group of Australian researchers have taken those investigations a step further to see if the changes persist over a longer time frame. They recruited healthy people who were either overweight or obese and put them on a highly restricted diet that led them to lose at least 10 percent of their body weight. They then kept them on a diet to maintain that weight loss. A year later, the researchers found that the participants’ metabolism and hormone levels had not returned to the levels before the study started.
The study, being published Thursday in The New England Journal of Medicine, is small and far from perfect, but confirms their convictions about why it is so hard to lose weight and keep it off, say obesity researchers who were not involved the study.
They cautioned that the study had only 50 subjects, and 16 of them quit or did not lose the required 10 percent of body weight. And while the hormones studied have a logical connection with weight gain, the researchers did not show that the hormones were causing the subjects to gain back their weight.
Nonetheless, said Dr. Rudolph Leibel, an obesity researcher at Columbia, while it is no surprise that hormone levels changed shortly after the participants lost weight, “what is impressive is that these changes don’t go away.”
Dr. Stephen Bloom, an obesity researcher at Hammersmith Hospital in London, said the study needed to be repeated under more rigorous conditions, but added, “It is showing something I believe in deeply — it is very hard to lose weight.” And the reason, he said, is that “your hormones work against you.”
In the study, Joseph Proietto and his colleagues at the University of Melbourne recruited people who weighed an average of 209 pounds. At the start of the study, his team measured the participants’ hormone levels and assessed their hunger and appetites after they ate a boiled egg, toast, margarine, orange juice and crackers for breakfast. The dieters then spent 10 weeks on a very low calorie regimen of 500 to 550 calories a day intended to makes them lose 10 percent of their body weight. In fact, their weight loss averaged 14 percent, or 29 pounds. As expected, their hormone levels changed in a way that increased their appetites, and indeed they were hungrier than when they started the study.
They were then given diets intended to maintain their weight loss. A year after the subjects had lost the weight, the researchers repeated their measurements. The subjects were gaining the weight back despite the maintenance diet — on average, gaining back half of what they had lost — and the hormone levels offered a possible explanation.
One hormone, leptin, which tells the brain how much body fat is present, fell by two-thirds immediately after the subjects lost weight. When leptin falls, appetite increases and metabolism slows. A year after the weight loss diet, leptin levels were still one-third lower than they were at the start of the study, and leptin levels increased as subjects regained their weight.
Other hormones that stimulate hunger, in particular ghrelin, whose levels increased, and peptide YY, whose levels decreased, were also changed a year later in a way that made the subjects’ appetites stronger than at the start of the study.
The results show, once again, Dr. Leibel said, that losing weight “is not a neutral event,” and that it is no accident that more than 90 percent of people who lose a lot of weight gain it back. “You are putting your body into a circumstance it will resist,” he said. “You are, in a sense, more metabolically normal when you are at a higher body weight.”
A solution might be to restore hormones to normal levels by giving drugs after dieters lose weight. But it is also possible, said Dr. Jules Hirsch of Rockefeller University, that researchers just do not know enough about obesity to prescribe solutions.
One thing is clear, he said: “A vast effort to persuade the public to change its habits just hasn’t prevented or cured obesity.
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“We need more knowledge,” Dr. Hirsch said. “Condemning the public for their uncontrollable hedonism and the food industry for its inequities just doesn’t seem to be turning the tide.”
]]>September 8, 2011, Los Angeles Times, Jeannine Stein
Medicare could save billions of dollars if people who were pre-diabetic or at risk for cardiovascular disease took part in community-based weight-loss programs, a study finds.
Researchers projected cost savings for the government healthcare program if millions of people in the U.S. age 60 to 64 participated in a program that helped them lose weight and gain more healthful lifestyle habits. They based their findings on an existing YMCA diabetes prevention program that is, as of this year, at 50 facilities in 24 states. In a study of a similar program, participants lost an average 7% of their body weight and maintained that over 2.8 years. The prevalence of diabetes went down 71% among people age 60 and older.
Their projection was based on a scenario in which the program would roll out across the country and target adults age 60 to 64–those not eligible for Medicare yet–who are pre-diabetic, with a body mass index greater than 24 (considered overweight or obese), and who show risk factors for cardiovascular disease. Under the proposal, funding would come from the Centers for Disease Control and Prevention’s National Diabetes Prevention Program and the Prevention and Public Health Trust Fund. Both were established by the Affordable Care Act.
The study authors estimated Medicare savings over a 10-year period as well as for a person’s lifetime, and based them on two participation rates from results of a pilot study: one in which 70% of people took part, and one in which 55% of people took part.
If 70% of eligible people age 60 to 64 with a BMI of 24 or higher enrolled, the program would cost $590 million. But that would also mean a net savings of $2.3 billion to Medicare over 10 years and a net lifetime savings of $9.3 billion. At the 55% participation rate, the net savings would be $1.8 billion over 10 years and $7.3 billion over participants’ lifetime.
Include overweight and obese people who also have the cardiovascular disease markers of high blood pressure and high cholesterol (even if they’re not pre-diabetic) and that would add an additional $1.4 billion in savings over 10 years and an extra $5.8 billion in lifetime savings, with 70% enrollment. With 55% participation there would be a net savings of $1.2 billion over 10 years and $4.6 billion in lifetime savings.
“Diabetes is expensive to treat,” says Kenneth Thorpe, a professor at Emory University, in a news release. Thorpe, lead author of the study that was released Thursday in the journal Health Affairs, added, “Most of the growth in health care spending is linked to rising rates of diabetes, cholesterol, and high blood pressure–all conditions that weight loss can help reduce. Why not shift the focus to keeping people healthy?”
via Enrolling in weight-loss programs could save Medicare billions – latimes.com.
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August 30, 2011, Los Angeles Times, Jeanine Stein
Teens love text messages–and those texts may help them lose weight, if they’re done right. A study tested out various types of weight management-themed text messages on overweight teens to see what they liked, finding that they favored positive messages but disliked thoughtful questions.
Overweight and obese teens can be a tough crowd when it comes to weight-loss interventions–many have a tough time adopting more healthful diet and exercise routines. Researchers from the University of Michigan thought tailored text messages might be a good way to help teens adopt lifestyle changes, since texts have been successful in helping others drop bad habits. The study appeared online recently in the journal Obesity.
To determine what kinds of text messages would be most effective the researchers set up four focus groups comprised of 24 male and female teens who were part of a weight management program. Six different message types were tested: testimonials, meal and recipe ideas, targeted tips, reflective questions, feedback questions and tailored messages.
Overall, the teens were excited about the text messages, but not everything passed muster. They liked messages that told them what to do, such as recipes and testimonials about weight-loss strategies–those the teens found encouraging, but only when they came from another teen.
Participants also liked positive, uplifting messages. Exclamations and emoticons were OK–especially for congratulating weight loss–but colloquialisms typically used by teens weren’t. “LOL,” for example, was not well received.
They also didn’t like mentions of unhealthful behaviors and foods, even if they were accompanied by references to healthier options. Mentioning unhealthful foods, for example, might trigger them to crave those items.
They weren’t crazy about reflective questions, especially when there were several in a row, such as, “What does being healthy mean for you? How does screen time fit in with your goals? How could cutting back on it help improve your health?” Teens thought there were too many and weren’t sure which to answer first. In discussions the teens said they wanted to be told what to do, instead of having to come up with their own weight-loss strategies.
That surprised the study authors, who noted that some studies find that people tend to stick with behavior changes if they’ve generated them more than if they come from other sources. But, they added, the delivery method may be to blame–a string of thoughtful questions may be too much to handle with a 140-character text messaging system.
The next step, said the authors, is to test the texts out on teens to see if they actually have any effect on weight loss.
via Texts may help teens lose weight – latimes.com.
Medpage Today, John Gever, August 25, 2011
Common rules of thumb exaggerate how much weight people will lose from a given dietary calorie reduction, leading to unrealistic expectations and disappointment, researchers said.
Whereas patients are often told that cutting 500 calories a day will let them lose a pound a week, a more realistic formula is that such a caloric reduction would lead to a 50-pound loss over three or more years, according to Kevin D. Hall, PhD, of the National Institute of Diabetes and Digestive and Kidney Diseases in Bethesda, Md., and colleagues.
Even then, they explained in the Aug. 27 issue of The Lancet — a special edition devoted to obesity — such weight loss is possible only if the calorie reduction is actually maintained over that time.
The standard rules — endorsed by the National Institutes of Health and the American Dietetic Association, among others — fail to consider that human metabolism responds dynamically to changes in diet and body composition, Hall and colleagues asserted.
If a 300-pound dieter could really lose a pound a week by cutting his regular diet by 500 calories, he would vanish entirely in six years.
“This ubiquitous weight-loss rule (also known as the 3,500 [calorie]-per-pound rule) was derived by estimation of the energy content of weight lost, but it ignores dynamic physiological adaptations to altered body weight that lead to changes of both the resting metabolic rate as well as the energy cost of physical activity,” the researchers wrote.
When people gain weight, their baseline energy needs increase, to keep the extra tissue alive and to move it around. Likewise, when weight is lost, their baseline needs decrease.
So when people cut calories below the baseline requirement — thereby triggering weight loss — the gap between their intake and their baseline energy needs begins to shrink. At some point, it may disappear altogether, at which point weight loss stops.
Hall and colleagues put together what they said was a better model of caloric intake and resultant weight loss, incorporating feedback mechanisms to reflect metabolic changes over time in response to diet and body weight.
It indicated that weight change in response to caloric restriction occurs over a relatively long period of time.
Each reduction of 100 kilojoules daily — 24 calories — in intake eventually leads to a loss of 1 kg (2.2 lbs) in body weight, the researchers determined. But only half that loss occurs in the first year. In three years, 95% of the ultimate loss will be realized.
On the flip side, using data from previous studies, Hall and colleagues said their calculations suggest that the U.S. population has a persistent excess energy intake of 30 kilojoules (7.2 calories) per day, explaining the increasing prevalence of overweight and obesity.
For the population to return to body mass index values that prevailed in the 1970s, average diets would need to shrink by about 220 calories per day.
The researchers pointed out that these figures are averages for the adult population. Individuals’ metabolic requirements for sustaining a given body mass vary substantially.
Consequently, “a given diet results in an uncertain degree of energy deficit,” Hall and colleagues wrote.
The findings have important implications for policy, the researchers argued.
For example, they pointed to a 2010 policy paper from the U.S. Department of Agriculture, which included an estimate that a 20% tax on sugar-sweetened drinks would reduce average energy intake by 40 calories.
Using the standard 3,500 calorie-per-pound rule, the paper indicated that an average weight loss of about 1.8 kg (4 lbs.) per year could be expected — “incorrectly,” Hall and colleagues contended.
Their model shows that it would actually take five years to achieve that level of average weight loss.
“We suggest that unrealistic weight loss expectations obtained by erroneous use of the static dieting rule should be replaced by our methods to assess other population-wide and more targeted obesity prevention interventions,” the researchers wrote.
They also pointed out that, in evaluating interventions, the model can also take account of physical activity and its effects on body weight and metabolism.
On the other hand, a limitation is that “it assumes perfect adherence to the intervention” and also doesn’t automatically include increases in food intake that may accompany the start of an exercise program.
The problem, of course, is that adherence is usually anything but perfect. Moreover, it can be compounded by the long lag between changes in diet and changes in body weight, according to Hall and colleagues.
One manifestation is that patients lose weight while on a program and continue to do so — for a time — after they revert to their former lifestyle.
“The dieter might then incorrectly infer that adherence is not essential for continuing weight loss when, in fact, impending weight regain has already been set in motion,” the researchers indicated
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August 14, 2011, Weight loss surgery channel
Telling patients to use sheer willpower and make smarter food choices is not an effective means of treating obesity, according to a team of researchers at Rush University Medical Center in Chicago.
Rather, obesity counseling should focus on the brain’s tendency to fixate on high-sugar and high-fat foods, and address ways of avoiding environmental triggers.
“The brain is not really set up well to handle food in a way that would promote weight loss,” said clinical psychologist and obesity researcher Bradley Appelhans, Ph.D., lead author of the article promoting a neurobehavioral model to obesity care that appears in the August issue of the Journal of the American Dietetic Association.
Under the neurobehavioral approach, Western culture — with its modern conveniences and the constant lure of fast food — is the real threat.
Research indicates that three responses in the brain cause people to struggle with obesity: food reward, inhibitory control, and time discounting.
Food reward is controlled by the mesolimbic dopamine system. Dopamine is the chemical responsible for signaling rewards in the brain. Obese people’s brains release less dopamine in response to food as compared to non-obese people, studies show, and so they consume more food than others.
Inhibitory control is a behavioral function in the prefrontal cortex that controls the ability to avoid cravings, while time discounting is a person’s tendency to devalue delayed rewards.
“Most of us would rather receive $200 today rather than $300 a year from now,” noted Dr. Appelhans.
Similarly, many people would rather have the instant gratification of a candy bar at the checkout counter than the delayed gratification of a healthier weight. In order for a person to lose weight, they must choose delayed rewards over immediate rewards.
“In the current environment, the brain’s ability to inhibit eating is continually being tested.” Dr. Appelhans said. “Counselors can help patients control their weight through strategies focused on the interaction between the brain and the environment, rather than the traditional approach of encouraging patients to simply ignore or fight food cravings and eat fewer calories than they expend.”
Stress also is a major contributor to obesity because it disrupts the brain mechanism responsible for inhibitory control and promote over eating.
To avoid gaining weight, researchers advise patients to remove the temptations of high fat foods from their home or work environments, shop with a grocery list or online, and avoid buffets and restaurants that challenge inhibitory control practice. Cooking at home three times a week or more and practicing stress management techniques can also reduce the risk of giving into high fat fare, Dr. Appelhans said.
via Obesity Counseling Should Address the Brain, Not the Food |Weight Loss Surgery Channel.
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August 13, 2011, AAP
SCIENTISTS have come up with a novel way of helping overweight people drop some kilos – retraining their taste buds.
Australian researchers have found that overweight and obese people who regularly tuck into fatty foods are less able to taste fat.
As fat promotes fullness, if a person is insensitive to fat their body will not send out signals telling them they are full and need to stop eating.
However the researchers found that switching to a low fat diet made people more sensitive to tasting fat, increasing their ability to feel full faster and stop overeating.
The findings by scientists at Deakin University’s Centre for Physical Activity and Nutrition Research builds on their discovery in 2010 of a taste bud that detects fat.
For the latest study, 19 people of a healthy weight and another 12 who were overweight or obese were put on a low-fat diet for four weeks and a high-fat diet for another month.
The participants were all given samples of custard after following the low-fat diet and each could taste which ones had lower amounts of fat.
However when they switched to a high-fat diet it was only the people of a healthy weight who showed any change in their ability to recognise different fat levels.
While the healthy weight people were less able to taste different fat levels in custard, those who were overweight or obese showed no change in their sensitivity to fat.
The centre’s Associate Professor Russell Keast said the study showed being on a low-fat diet makes overweight and obese people more sensitive to fatty tastes.
“It was interesting that we could improve fat sensitivity of overweight/obese people with low fat diets – in a sense train their tastebuds to be more sensitive to fat,” he said.
“This provides hope that their body may be able to adapt over a period of time, thereby responding to dietary fat in a similar way as a healthy weight person.”
But Assoc Prof Keast said simply switching to a low fat diet was not necessarily the only way to help obese people lose weight.
Scientists still did not have a complete understanding of the role genetics played in obesity and more studies were needed to determine if different types of fat could affect how sensitive people become to detecting fatty foods, he said.
Another possible key to weight loss could be linked to whether specific foods or different types of fat can make people less or more sensitive to tasting fat.
Assoc Prof Keast said the centre’s study had revealed that the participants who were less sensitive to fatty tastes tended to eat more meat and high-fat dairy foods.
He said if scientists could work out whether eating certain fats helped people feel fuller, the concentrations of those specific fats could be increased in foods which could possibly then be marketed as weight-loss products.
“Everything comes down to the response to what you are eating,” he said.
“It’s certainly not as easy as saying this is the only solution.
“Overweight and obesity is a result of multiple factors and excess consumption of fat is only one of them.”
The study was published in the International Journal of Obesity and Clinical Nutrition.
Los Angeles Times, August 8, 2011, Jeanine Stein
Obese men who want to improve their sexual health might have another solution besides their erectile dysfunction drugs. A study finds that overweight men who lost just 5% of their weight over eight weeks saw improvements in erectile dysfunction, sexual desire and urinary tract symptoms.
The small study focused on 31 obese men with a body mass index of 30 or greater and who had Type 2 diabetes. Some were put on a low-calorie diet that included liquid meal replacements and others were assigned to a high-protein, low-fat diet that decreased their calorie intake by 600 calories a day. For 42 weeks afterward the participants stayed on the high-protein diet, or were switched to it.
Those on the low-calorie diet lost 10% of their body weight and 10% off their waist circumference, and those on the high-protein diet lost 5% of their weight and waist circumference. But participants in both groups improved their plasma glucose, LDL (“bad”) cholesterol, erectile function, urinary symptoms, sexual desire and endothelial function. Endothelial cells form a thin layer and line the inside surface of blood vessels. Dysfunctional cells can be a marker for vascular disease and may signal early development of athersclerosis.
Weight loss and improvement of insulin sensitivity, the authors wrote, could increase the production of testicular testosterone, and in turn, enhance sexual function.
“Our findings are consistent with the evidence that not only erectile function, but also lower urinary tract symptoms are a marker of cardio-metabolic risk,” said Dr. Gary Wittert of the University of Adelaide in Australia, in a news release. “The evidence that improvement can be achieved by modest weight loss, in particular when a diet is of high nutritional quality, is of public health significance in framing public health messages that resonate with men.”
The study was released Monday in the Journal of Sexual Medicine.
Weight loss may help obese men improve their sexual health – latimes.com.
August 3, 2011, Reuters/Tribune
Dieting to lose weight may not help older overweight adults live any longer, suggests a new study.
But dropping a few pounds on purpose also does not seem to cause any harm to the elderly — which had been a concern raised by previous studies, researchers wrote in the American Journal of Clinical Nutrition.
“There is a general sense in geriatrics…that weight-loss is a bad thing,” said study author Stephen Kritchevsky, from Wake Forest Baptist Medical Center in Winston-Salem, North Carolina.
Improvements in diet and weight loss in the overweight and obese are linked to blood pressure, cholesterol and diabetes benefits, including in the elderly.
Still, “there’s been a little bit of a conundrum on whether it’s a wise thing or not to ask an overweight older adult to lose weight.”
That’s because some research has linked weight loss in older adults with a higher rate of death — probably because unintentional weight loss in the elderly is often due to an underlying illness, Kritchevsky added.
While the new findings don’t show that dropping weight can extend an older adult’s life, “if an older person is overweight or obese and has weight-related health conditions, they should not be concerned that losing weight would be bad for them,” he concluded.
For now, Kritchevsky called the findings “a reassuring message that weight loss is potentially beneficial regardless of your age, if you’re overweight or obese.”
And even if losing weight might not add a lot of years to an elderly person’s life, it can have many other health benefits, he added — from easing disease risks to making activities like walking up the stairs easier and reducing osteoarthritis pain.
via Dropping weight won’t add years in elderly: Study – The Express Tribune.
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August 2, 2011, TIME, Meredith Melnick
Lose weight. That’s often the first advice from doctors to their pre-diabetic patients. But while losing excess fat can help reverse Type 2 diabetes risk factors like insulin resistance and high blood-sugar levels, a new study finds that increasing muscle mass may also help lower risk of the metabolic disease.
According to lead researcher, Dr. Preethi Srikanthan, this may be good news for many people with pre-diabetes — a condition that results in higher-than-normal blood sugar, but does not qualify as diabetes — who have difficulty slimming down.
“Our findings suggest that beyond focusing on losing weight to improve metabolic health, there may be a role for maintaining fitness and building muscle mass,” Srikanthan, an assistant professor of medicine at the University of California, Los Angeles, David Geffen School of Medicine, said in a statement. “This is a welcome message for many overweight patients who experience difficulty in achieving weight loss, as any effort to get moving and keep fit should be seen as laudable and contributing to metabolic change.”
Srikanthan and colleagues based their study on data on 13,644 adults who participated in the U.S. National Health and Nutrition Examination Survey (NHANES) III between 1988 and 1994. Looking at the participants’ skeletal muscle index (SMI), a ratio of muscle mass to total body weight, researchers found an association between increasing SMI and a reduction in certain diabetes risk factors: for each 10% increase in SMI, there was an 11% decrease in insulin resistance and a 12% decrease in pre-diabetes.
The findings are in line with what is already known about the metabolic effects of muscle and fat. “Extra fat has bad effects, but more muscle has good effects. These data are also consistent with data we see on exercise, that it helps decrease diabetes risk, and that a lack of exercise and weight gain increase risk,” Daniel Rubin an assistant professor of medicine at Temple University School of Medicine, told USA Today.
The research was an extension of a 2009 study by the same UCLA team that found that people with high waist-to-hip ratios were at greater risk for diabetes. The team then began examining a subset of patients who had “sarcopenic obesity,” a condition marked by unusually high body fat and unusually low muscle mass.
The following year, using data from NHANES, the team was able to show that sarcopenic obesity was associated with pre-diabetes and diabetes risk. But in this latest study, the team found that the association between muscle mass and pre-diabetes held, even among those who did not suffer from sarcopenic obesity.
The study will be published in the September issue of the Journal of Clinical Endocrinology and Metabolism.
Read more: http://healthland.time.com/2011/08/02/gains-in-muscle-mass-not-just-weight-loss-may-help-lower-diabetes-risk/#ixzz1TxIWRVSy
Gains in Muscle Mass, Not Just Weight Loss, May Help Lower Diabetes Risk – TIME Healthland.
July 31, News-Medical, Ananya Mandal
According to obesity expert and University of Melbourne professor of medicine Joseph Proietto the high failure rate of weight-loss programs could be explained by growing evidence that an obese person’s body is programmed to regain any weight that is lost. He said that authorities are wasting money on campaigns urging people to exercise and eat healthy food since obesity is “physiologically defended”.
He wrote in an opinion piece in The Medical Journal of Australia in which he said weight loss in obese people only led to changes in energy expenditure and hunger-controlling hormones that encouraged weight gain. He said, “It is likely that it is these physiological adaptations that make it so difficult to maintain weight loss… Importantly … in those who are already obese, public health messages encouraging people to eat healthy food and exercise are unlikely to have a long-term impact on their weight.”
Professor Proietto said the weight-control clinic he ran at the Austin Hospital was overwhelmed with demand, with a two-year waiting period. But the hospital was funded to do no more than 20 gastric banding operations a year. He said political leaders were ignoring the biological reasons for obesity by focusing on lifestyle messages and providing only limited funding for bariatric surgery, which had been shown to achieve long-term weight loss. He added, “All the money is put into giving messages on television, but actually that doesn’t work – you can’t convince someone not to eat who is hungry… If a good tablet came along it would not make it on the PBS [Pharmaceutical Benefits Scheme] because everybody says obesity is a lifestyle disorder only and all you have to do is change your habits… We don’t need tablets to lose weight – but we do need them to keep it off.”
On a brighter note he said the important point was to prevent obesity, particularly in children, but more resources were needed for people who were already obese. He said gastric banding surgery could reverse obesity-related conditions such as type 2 diabetes and obstructive sleep apnea. “’We must help the long-suffering obese in their struggle to maintain a reduced weight…In the absence of safe, effective pharmacological agents that can be used long-term, bariatric surgery is the most successful intervention for sustained weight loss. Why is it not more often conducted in public hospitals?”
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