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CU Anschutz study reveals exercise is more critical than diet to maintain weight loss

Exercise

A new study from the University of Colorado Anschutz Health and Wellness Center (AHWC) at the CU Anschutz Medical Campus revealed physical activity does more to maintain substantial weight loss than diet.

The study, published in the March issue of Obesity, was selected as the Editor’s Choice article.

Danielle Ostendorf, PhD, a postdoctoral fellow at the CU Anschutz Health and Wellness Center
Danielle Ostendorf, PhD, a postdoctoral fellow at the CU Anschutz Health and Wellness Center

“This study addresses the difficult question of why so many people struggle to keep weight off over a long period. By providing evidence that a group of successful weight-loss maintainers engages in high levels of physical activity to prevent weight regain – rather than chronically restricting their energy intake – is a step forward to clarifying the relationship between exercise and weight-loss maintenance,” said Danielle Ostendorf, PhD, a postdoctoral fellow at the CU Anschutz Health and Wellness Center.

The findings reveal that successful weight-loss maintainers rely on physical activity to remain in energy balance (rather than chronic restriction of dietary intake) to avoid weight regain. In the study, successful weight-loss maintainers are individuals who maintain a reduced body weight of 30 pounds or more for over a year.

Key findings include:

  • The total calories burned (and consumed) each day by weight-loss maintainers was significantly higher (300 kcal/day) compared with that in individuals with normal body weight controls but was not significantly different from that in the individuals with overweight/obesity.
  • Notably, of the total calories burned, the amount burned in physical activity by weight-loss maintainers was significantly higher (180 kcal/day) compared with that in both individuals of normal body weight and individuals with overweight/obesity. Despite the higher energy cost of moving a larger body mass incurred by individuals with overweight/obesity, weight-loss maintainers were burning more energy in physical activity, suggesting they were moving more.
  • This is supported by the fact that the weight-loss maintainer group also demonstrated significantly higher levels of steps per day (12,000 steps per day) compared to participants at a normal body weight (9,000 steps per day) and participants with overweight/obesity (6,500 steps per day).

“Our findings suggest that this group of successful weight-loss maintainers are consuming a similar number of calories per day as individuals with overweight and obesity but appear to avoid weight regain by compensating for this with high levels of physical activity,” said Victoria A. Catenacci, MD, a weight management physician and researcher at CU Anschutz Medical Campus.

Victoria A. Catenacci, MD, a weight management physician and researcher at CU Anschutz Medical Campus
Victoria A. Catenacci, MD, a weight management physician and researcher at CU Anschutz Medical Campus

The study looked at successful weight-loss maintainers compared to two other groups: controls with normal body weight (Body Mass Index (BMI) similar to the current BMI of the weight-loss maintainers); and controls with overweight/obesity (whose current BMI was similar to the pre-weight-loss BMI of the maintainers).  The weight-loss maintainers had a body weight of around 150 pounds, which was similar to the normal weight controls, while the controls with overweight and obesity had a body weight of around 213 pounds.

This study is one of the few to measure total daily energy expenditure in weight-reduced individuals using the gold standard doubly labeled water method.  This method allows researchers to precisely determine an individual’s energy expenditure through collecting urine samples over one to two weeks after people are given a dose of doubly labeled water. Doubly labeled water is water in which both the hydrogen and the oxygen atoms have been replaced (i.e. labeled) with an uncommon isotope of these elements for tracing purposes.

The measure of total daily energy expenditure from doubly labeled water also provides an estimate of energy intake when people are weight stable, as they were in this study. Prior studies used questionnaires or diet diaries to measure energy intake, which have significant limitations.

The researchers also measured each individual’s resting metabolic rate in order to understand how much of the total daily energy expenditure is from energy expended at rest versus energy expended during physical activity. Prior studies used self-reported measures or activity monitors to measure physical activity, which are techniques that cannot provide the same accuracy.

The findings are consistent with results from the longitudinal study of “The Biggest Loser” contestants, where physical activity energy expenditure was strongly correlated with weight loss and weight gain after six years.

 

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Is there a penalty for weight loss?

Losing weight is difficult for most people, and keeping it off is invariably a struggle. Some studies have suggested that a greater than expected reduction in resting metabolic rate — the amount of calories your body burns at rest — may be one factor that contributes to weight regain after weight loss.

Researchers at the University of Colorado Anschutz Health and Wellness Center (AHWC) recently conducted a study that suggests that resting metabolism is not lower than expected in a group of successful weight loss maintainers. These results differ from a 2016 study which focused on a small group of subjects from “The Biggest Loser” televised weight loss competition. That study, conducted by a federal research center, followed 16 men and women with class III obesity who lost an average 120 pounds in just a few months— and found they all put most of the weight back on over a period of years.

Resting metabolic rate is determined by the calories used by muscle, organs such as the liver and kidney, and to a lesser extent by body fat. The amount of calories the body burns at rest is known to decrease after weight loss as body size decreases, and this is one reason why it is so hard to maintain weight loss. “To keep the scale from titling back to your original body weight, you will need to eat fewer calories or burn more calories in exercise to stay in energy balance at your new body size,” says Victoria A. Catenacci, MD, a weight management physician and researcher at CU.

Controversial question

A question that generates some controversy, Catenacci said, is whether there is an additional “metabolic penalty” that occurs with weight loss — a decrease in resting metabolism beyond what is predicted from changes in body composition.

Victoria Catenacci
Victoria A. Catenacci, MD, a weight management physician and researcher

“The Biggest Loser” study suggested that six years after the weight loss competition ended, the contestants suffered an additional metabolic penalty due to their weight loss. Their resting metabolism had slowed to the point that their bodies were burning 500 calories a day less on average than the researchers predicted they should be based on their new body size.

CU researchers noted that the resting metabolism suppression of 500 calories a day had not been seen previously in weight-loss study literature; previous estimates of the metabolic penalty due to weight loss typically suggested resting metabolic rate was at most 40-150 calories below predicted values.

Significant health benefits

“News articles that came out after ‘The Biggest Loser’ study basically said, ‘Weight loss is a futile effort, so why bother?’” said Danielle Ostendorf, MS, ACSM-CEP, PhD, a postdoctoral fellow in the School of Medicine’s Department of Medicine at AHWC, and a recent graduate from the Colorado School of Public Health. Ostendorf was the lead author of the study recently published in The American Journal of Clinical Nutrition. “That’s problematic, because even some weight loss can result in significant health benefits.”

The CU study addresses the question of whether resting metabolic rate is lower than predicted in a group of individuals who are maintaining a weight loss. The CU researchers reached a different conclusion: “Results from our study suggest that sustained weight loss may not always result in a substantial, disproportionately low REE that inexorably predisposes individuals to regain weight,” Catenacci said.

Danielle Ostendorf
Danielle Ostendorf, MS, ACSM-CEP, PhD, a postdoctoral fellow in the Department of Medicine at the CU Anschutz Health and Wellness Center

The CU study divided 102 participants, ages 16 to 65, into three groups: weight-loss maintainers (individuals who had lost at least 30 pounds and kept it off for at least a year); controls of normal body weight (matched to the current Body Mass Index (BMI) of the weight-loss maintainers); and controls with overweight/obesity (matched to the pre-weight-loss BMI of the maintainers).

Comparing resting metabolism

“After comparing resting metabolism in weight loss maintainers to controls, and using several published equations to predict resting metabolism, we didn’t find much evidence of suppression of resting metabolic rate in our group of successful weight loss maintainers,” Ostendorf said. “We found that after adjusting for differences in body composition, resting metabolism in successful weight loss maintainers was on average only 14 calories a day lower than predicted.” However, there was variability with some weight loss maintainers showing a lower-than-predicted resting metabolic rate (by as much as 250 calories a day), whereas others showed that their resting metabolic rate was higher than predicted (by up to 150 calories a day).”

The CU team acknowledges that “The Biggest Loser” research used a stronger study design of longitudinal data collection (following each individual over time) compared to the cross-sectional design of its study. In addition, the CU study only looked at people who had been successful in weight loss maintenance. However, they noted that “The Biggest Loser” analysis was a small study of a group of individuals who exhibited extreme obesity. “These were people who lost a lot of weight over a very short period of time, so it may not represent what people experience when losing weight with more conventional lifestyle weight loss strategies,” Catenacci said. “To take that data and extrapolate it into this message that weight loss is futile — when that’s not the way the majority of people lose weight — just seemed concerning.”

Delving deeper

The CU team plans to delve deeper into this issue using data collected in an ongoing weight loss study in which participants are randomized to a lifestyle weight loss program involving either daily calorie restriction or intermittent fasting.  It has a cohort in the weight-loss program which is currently at the six-month mark; a second cohort is being assembled to start the program in January (see sidebar).

“It’s important to show that there is hope for people who want to lose weight,” Ostendorf said. “But it’s also important to recognize that a metabolic penalty may exist for some people who lose weight. It’s definitely a sensitive issue.”

WANT TO BE IN A WEIGHT-LOSS STUDY?

Volunteers are needed for a research study to learn more about the best eating patterns for weight loss within a 12-month behavioral weight loss program.

To be eligible you must:

  • Be a man or woman between 18 and 55
  • Be generally healthy without diabetes or heart disease
  • Be a non-smoker
  • Not currently exercising regularly
  • Have a BMI between 27 and 40kg/m2
  • Live or work within 30 minutes of the CU Anschutz Medical Campus

For more information about what you will receive, please contact the study team at DRIFT2@ucdenver.edu

There is strong data to suggest that humans are biologically predisposed to regaining lost weight. Factors other than changes in resting metabolism, such as increases in appetite and decreases in the amount of calories the body burns during exercise, may also play a role. So essentially, Catenacci said, losing weight and keeping it off is not as simple as just willpower.

“These studies don’t solve the issue by any means,” she added. “They are pieces in the puzzle. More data is needed before we draw any sweeping conclusions about the presence or absence of a metabolic penalty.”

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Liver clinic targets silent epidemic with team approach

After watching the cafeteria lady’s husband die under his team’s care, Thomas Jensen, MD, began focusing on preventing the scenario from happening again. The patient, who had been unknowingly suffering from liver disease, had lost all function of the organ, leaving Jensen and his colleagues nearly helpless.

Wieland and Jensen
Amanda Wieland, MD, and Thomas Jensen, MD, flank a FibroScan® machine, which they often use to quickly and non-invasively assess patients’ liver health. The pair teamed up to launch the Multidisciplinary Nonalcoholic Fatty Liver Disease Clinic (NAFLD) in hopes of slowing an increasing epidemic.

Today, as an assistant professor on the University of Colorado Anschutz Medical Campus, Jensen’s memory fuels his outreach aimed at detecting what has become the most prevalent chronic liver disease in the United States. Rising in tandem with the obesity epidemic, Nonalcoholic Fatty Liver Disease (NAFLD) now strikes children as well as adults and is soon expected to become the top reason for liver transplants in this country.

“It was one of the toughest cases I saw in residency,” said Jensen, who joined the School of Medicine’s Division of Endocrinology, Metabolism and Diabetes in 2016. “He was intubated and on multiple medications and was very difficult to manage. I just remember thinking to myself: We need to have a better way of finding these people before it’s too late.”

Answering a call

Today, Jensen and Amanda Wieland, MD, of the Division of Gastroenterology and Hepatology, have launched the Multidisciplinary NAFLD Clinic, using a team approach that combines their expertise with that of top experts across the campus in decreasing the disease’s burden on patients and the health care system.

Red flags for NAFLD in patients

 

Obesity

Visceral fat (increased waist circumference)

Metabolic syndrome

Insulin resistance

Type 2 diabetes

High blood pressure

Sleep apnea

Some lipid disorders

High triglycerides

Some medications (e.g., some HIV drugs, Tamoxifen, Methotrexate, some steroids)

“Roughly 30 percent of the population has Fatty Liver Disease, doubling in incidence since the 1990s,” Jensen said. “We know that it’s not only preventable, but it also can be reversible largely through diet and exercise,” said Jensen, who hopes to extend the clinic hours with the addition of SOM’s Emily Schonfeld, MD, a gastroenterologist, to the staff this fall.

NAFLD – which results when fatty deposits (steatosis) collect in the liver because of something other than alcohol consumption – has strong links to obesity and heart and metabolic disease. While it strikes 8 percent of the lean population, NAFLD affects nearly 70 percent of diabetics and 80 percent of the morbidly obese.

If the cause goes unaddressed, liver inflammation, scarring and cell death (nonalcoholic steatohepatitis, or NASH) can result, ultimately leading to permanent tissue damage, or cirrhosis.

Missing a silent killer

With top-of-the-line screening equipment, the clinic’s team can identify cases and determine the severity, generally non-invasively, steering patients down the road to reversal. Jensen hopes more patients and primary care doctors, who often don’t have the knowledge, ability or time to effectively treat NAFLD patients, will seek expert care for themselves or their patients.

While primary care physicians routinely check liver function with blood tests, the Dallas Heart Study found the lab work was not a reliable marker, leaving patients undiagnosed, Jensen said. “On ultrasound, researchers found that up to 80 percent of those patients who did have fatty liver had normal-looking enzymes,” Jensen said.

Because doctors once thought simple steatosis would never progress to inflammation and scarring, non-specialists sometimes downplay early NAFLD, Jensen said. But studies now suggest within a six-year period, up to 40 percent of those patients do develop NASH.

“So, our sense is that it’s not only important to screen but to look at the risk factors that might suggest patients are susceptible and to monitor those patients.”

Life-changing diagnosis

Having lost his brother 10 years his junior last year to long-undiagnosed NAFLD, Aurora resident Dennis Ipsen considers himself lucky that his doctor sent him to Jensen and Wieland. The pair quickly detected the disease and began monitoring Ipsen.

“That’s what I liked the most,” Ipsen said of Jensen’s expertise and team approach. “He was Johnny-on-the-spot looking for this, and he knew what he was dealing with, and he brought in the other doctor very quickly,” said Ipsen, who has diabetes and heart disease. “The sooner it’s detected, the better off you are.”

Ipsen’s only new directive so far: maintain his chosen Weight Watchers diet plan. “I’m hoping that’s all I need,” he said.

“I just remember thinking to myself: We need to have a better way of finding these people before it’s too late.” – Thomas Jensen, MD

Rx: Weight loss

A healthy diet, exercise and weight loss is often the only prescription necessary with early diagnosis, Jensen said. “We know that with a 5 percent weight loss, you can reverse the level of fat in the liver,” he said. “And with a greater-than 10 percent weight loss, you can even start seeing reversal of fibrosis (early stages of scarring).”

At the NAFLD clinic, patients receive counseling on controlling related conditions and on ways of achieving weight loss, from fitness apps to bariatric surgery. “I had an obese patient with moderate steatosis,” Jensen said. She was a candidate for bariatric surgery and opted for that route. One month and 15 pounds later, a recheck found her fatty liver was completely resolved, Jensen said.

In addition to the Metabolic and Bariatric Program for severely overweight cases, the NAFLD clinic works closely with the CU Anschutz Health and Wellness Center in helping patients master lifestyle changes and achieve weight loss.

Keeping the faith

Valerie Frank family
Valerie Frank stands front and center of her family, which includes eight grandsons. Frank travels from her Sterling home to the CU Anschutz Medical Campus for specialist care for liver disease.

Although Valerie Frank’s disease had progressed to cirrhosis by the time she found the clinic, the Sterling resident dropped more than 40 pounds since diagnosis and holds out hope that Jensen’s and Wieland’s care can keep complications at bay.

“It’s still good to know,” said Frank, who has diabetes and spent more than a year seeing doctors and undergoing tests trying to find an answer for fatigue and abnormal blood work. She finally told her doctor she gave up. “And he said: Let’s try one last thing. Let’s have you see Dr. Jensen and Dr. Wieland at UCHealth.”

Three weeks later, after making the two-plus-hour trip from her Sterling home, Frank was diagnosed. Now, despite the drive and higher out-of-pocket costs, Frank said she will continue under the doctors’ care for as long as they can help her and would encourage other liver patients to do the same.

“Absolutely. From the minute I walked in, I felt a connection with them both,” said the mother of three and grandmother of eight grandsons. With cirrhosis, her prognosis is not certain, but she’s sure of one thing: The doctors are doing everything they can to give her the best outcome. “I’m feeling well. I’m doing well. You can’t give up on hope,” she said. “I have total faith in them.”

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Lifestyle makeover: Wellness center study fuels transformation

With the words “morbidly obese” ringing in her ears and the thrill of crossing a 5K finish line fresh in her mind, Emily Cooley’s eyes stopped short on a Facebook post. The Anschutz Health and Wellness Center (AHWC) needed recruits for a weight-loss study. Having just been counseled by her doctor about the gravity of her weight, Cooley took it as a sign.

Emily Cooley before weight loss
A sense of accomplishment after finishing a 5K helped spur Emily Cooley’s dramatic weight loss.

That was 2-1/2 years ago. Today, the retail manager remains one of the most successful participants to take part in the 170-person study, shedding 80-plus pounds from her 5-foot-7, 240-pound frame and keeping it off, a feat that puts her in a rare group. Only one in five significant weight losers maintain the loss for more than one year, studies show.

“We can generally get individuals to lose weight, or to start exercising, but most are not successful at maintaining either of those two things long-term,” said Danielle Ostendorf, PhD, a physical activity epidemiologist on the University of Colorado Anschutz Medical Campus and recent Colorado School of Public Health graduate who worked on Cooley’s study. “Emily’s a perfect example of doing both things through lifestyle change.”

Turning points

Cooley, 39, who struggled with weight for years, had resigned herself to being a plus-size woman after her second daughter was born. But then her doctor showed her a Body Mass Index chart classifying her as morbidly obese and at risk of serious health problems.

“I want to be here for them, and not just on the sidelines.” – Emily Cooley

“Seeing morbidly obese in black and white freaked me out,” Cooley said. That, coupled with the life-long duty of parenthood, fueled her attitude reversal. “Being a mom definitely changed my perspective about it,” said the wife and mother of 4- and 6-year-old girls. “I want to be here for them, and not just on the sidelines.”

Feeling the satisfaction of finishing a 5K, which she mostly walked with the support of a runner friend, was another trigger. “I was so touched,” said Cooley, who now runs 5Ks with ease and has a BMI of 25 instead of 38. “I had finished it. I had made my goal.”

Expert guidance

The AHWC study, funded by the National Institutes of Health and led by the School of Medicine’s Victoria Catenacci, MD, helped keep her motivated through guidance, support and resources, from

Emily with family
Being around as long as possible for her family served as Emily Cooley’s “why” for losing weight.

the latest diet research to top-of-the-line fitness facilities, Cooley said. While working with a nutritionist, she learned she was absent-mindedly drinking calories, swallowing as many as 600 in a large frappe for breakfast and 300 in a large Coke for lunch.

Once her diet counseling changed things, Cooley was eating fewer calories all day than she generally consumed before noon.

Initially, Cooley was disappointed when she was placed in the “delayed-exercise” group during the study, spending the first six months on dieting only while her counterparts had exercise and diet training from the start. But now she sees the chance placement as luck. “I was focusing on only one big change at a time.”

Once exercise was added to her routine, Cooley had already dropped 50 pounds, making working out easier and less painful, she said. Participants’ exercise routines were ramped up slowly, from 20 minutes three times a week to 60 minutes five times a week, which Cooley and Ostendorf also suspect helped prevent burnout and injury, two threats that often sabotage overzealous new exercisers.

Powerful goals

Motivation, commitment and “SMART goals” set regularly along the way led to Cooley’s success, Ostendorf said, referring to Specific goals that are Measurable, Attainable, Realistic and Timely. “It could be: I want to lose 10 pounds in two months, or I want to lower my blood pressure 5 mm/Hg in six months,” she said.

Cooley largely uses a regular race plan for keeping on track, setting 5K and 10K dates with friends she’s met along the way throughout the year. “Then I tell my girls I have to go to the gym, so I can be strong for my race,” she said.

Setting an example for her daughters remains a big motivator for Cooley, who often hears: “Good job, Mommy!” and who walked a 5K with her 6-year-old this summer. Higher energy and better moods are other benefits, Cooley said, who has now set a lofty goal of completing a marathon this spring. “I just want to prove that I can.”

Curbing an epidemic: weight-loss star offers tips

With 70 percent of Americans overweight or obese, and their burgeoning waistlines costing the medical system as much as $190 billion annually, the Anschutz Health and Wellness Center’s research and promotion of weight loss helps curb an epidemic. Here are a few of study participant Emily Cooley’s tricks for success:

Be consistent.

“I will have one cheat meal once in a while, but then I get right back on track. I don’t do cheat weekends or cheat vacations anymore.”

Track exercise and calories.

“I still use MyFitnessPal. If I don’t, I underestimate what I eat.”

Have a powerful “why.”

“I can’t be morbidly obese. I have two little girls.”

Set consistent goals.

“I always have a race planned with friends; that helps keep me motivated.”

Make it fun.

“We make it a girls’ day out and do something like brunch after the race.”

Surround yourself with support.

“It just makes sense to have friends with the same goals.”

Plan.

For exercise: “I lay out my workout clothes the night before. And I have two alarms: a wake-up alarm nearby, and a get-out-of-bed alarm farther away.”

For diet: “I always have things like Clif bars or trail mix with me, so I don’t get caught out with nothing.”

Make it easy.

“My gym is only 10 minutes away.”

Forget the guilt.

“I used to feel guilty about taking time away from the girls. Now I realize if I’m not a healthy mom, I can’t be the best mom.”

Just do it.

“It’s never too late to lose weight.”

 

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trial commencing for Elipse Balloon

Enrollment for ENLIGHTEN, a United States clinical trial for the Elipse® Balloon – the world’s first and only procedureless™ gastric balloon for weight loss, has started at University of Colorado Hospital at the CU Anschutz Medical Campus.

The study is designed to evaluate the safety and efficacy of the Elipse Balloon in 400 individuals. It is administered by Allurion Technologies, a leader in the development of weight loss therapies. The study will be conducted at up to twelve sites in the United States. Dr. Shelby Sullivan, associate visiting professor of gastroenterology at the CU School of Medicine and a specialist in endoscopic bariatric weight-loss procedures is leading the trial in Colorado.

“We are excited to be the only center in Colorado enrolling patients in the ENLIGHTEN study, the first completely procedureless gastric balloon for weight loss,” Sullivan said. “A device like this which doesn’t require a procedure will lower the barriers for patients who need help with weight loss.”

The Elipse Balloon received its European Union CE mark in 2015 and is currently available in more than 40 weight loss centers in countries across Europe and the Middle East. Over 4,000 individuals have already been treated. Unlike other weight loss balloons, the Elipse Balloon is placed and removed without surgery, endoscopy, or anesthesia. It is swallowed in a capsule during a brief, outpatient office visit and remains in the stomach for approximately four months, after which it opens and passes naturally from the body.

“We are looking forward to adding to our global clinical trial experience with the Elipse Balloon,” said Ram Chuttani, M.D., Chief Medical Officer of Allurion. “Starting ENLIGHTEN is the first step toward bringing our flagship product to the United States where we can build upon the success we have had abroad.”

“The Elipse Balloon has the potential to revolutionize the way obesity is treated in the United States,” added Shantanu Gaur, M.D., Chief Executive Officer of Allurion. “Millions of Americans are struggling to lose weight, and they are calling for new options that are safe and effective. The ENLIGHTEN study is the next step in meeting this consumer need.”

The Elipse Balloon is made of a thin, flexible polymer film. The device is swallowed in a capsule and filled with liquid through a thin delivery catheter, which is then detached. The balloon remains in the stomach for approximately four months, after which it opens, allowing it to empty and pass naturally from the body without the need for a removal procedure.

A pilot clinical study and recent 135-patient clinical trial conducted outside the United States in overweight and obese individuals demonstrated an average weight loss of 29 to 33 pounds, approximately 15% of total body weight. Participants also saw improvements in their triglycerides, hemoglobin A1c (HbA1c) and quality of life.

Study visits will occur at the CU Anschutz Health and Wellness Center. Interested participants can learn more about the study, eligibility and how to register at http://balloontrial.com and http://clinicaltrials.gov/ct2/show/NCT03261453.

Image Source: Allurion Technologies

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Study: Light-intensity activities may play role in maintaining weight loss

Light-intensity activities such as washing the dishes, making the bed, and walking the dog may play a significant role in helping people maintain weight loss, according to a study by researchers at the Colorado School of Public Health (ColoradoSPH) and the University of Colorado Anschutz Health and Wellness Center.

The researchers noted that moderate-to-vigorous physical activity has been shown to strongly correlate with long-term weight-loss maintenance, but few studies have examined patterns of light-intensity activity and sedentary behavior in people who successfully keep the pounds off.

Woman walking a dog in the city
Simple light-intensity activities such as walking the dog could play a significant role in helping maintain weight loss.

“We conducted the study to better understand whether patterns of light-intensity activity and sedentary behavior were different in those who were successfully maintaining a weight loss compared to those who are not,” said Danielle Ostendorf, a CU Anschutz doctoral student in epidemiology who worked on the study.

Three groups of participants

In the National Institute of Health (NIH)-funded study (Principle Investigator Victoria A. Catenacci, MD), subjects wore a small, lightweight activity monitor (activPALTM, PAL Technologies LTD, Glasgow, Scotland) for seven days as they went about their normal activities. Participants were drawn from three groups:

  • weight-loss maintainers (individuals who had lost at least 30 pounds and were maintaining that weight loss for at least two years);
  • controls of normal body weight (matched to the current Body Mass Index (BMI) of the weight-loss maintainers);
  • controls with overweight/obesity (matched to the pre-weight-loss BMI of the maintainers).

Data from the 90 healthy adults in their mid-40s was collected and analyzed at the Center, with all three groups having a similar number of participants and distribution of age and sex. In a study such as this, it is critical to have groups with similar age and sex make-up, as physical activity varies by both age and sex.

Catenacci, a Department of Medicine faculty member in endocrinology, was lead author of the abstract. Ostendorf presented the abstract’s findings at the recent annual American Public Health Association conference in Denver.

Surprising results

“We had hypothesized that the weight-loss maintainers would be significantly different than the other two groups in terms of sedentary behavior and light activity,” Ostendorf said. “What was surprising was that the weight-loss maintainers and normal weight controls were similar in terms of their overall sedentary time and their time spent doing light activity, but differed dramatically from the controls with overweight/obesity in these parameters.”

Fitness room at University of Colorado Anschutz Health and Wellness Center
A woman works out on a treadmill at the University of Colorado Anschutz Health and Wellness Center.

The weight-loss maintainers and normal weight controls spent 4.8 hours (290 minutes) and 4.7 hours (281 minutes) a day doing light-intensity activity, respectively, while they were sedentary for 9.9 hours (596 minutes) and 10.3 hours (617 minutes) a day. The overweight/obese control arm spent 3.9 hours (234 minutes) a day in light-intensity activity and 10.9 hours (654 minutes) a day being sedentary. Compared to the controls with overweight/obesity, weight-loss maintainers and normal weight controls were doing about one hour more of light activity and one hour less of sedentary time each day.

Top student abstract

Danielle Ostendorf won the “Outstanding Student Research in Physical Activity” award at the recent American Public Health Association conference in Denver. It was selected among the top three student abstracts at the October conference.

Consistent with other studies, weight-loss maintainers also engaged in more exercise than controls of both types. Weight-loss maintainers spent 38.8 minutes a day doing moderate-to-vigorous exercise (accumulated in sustained bouts of 10 minute or more) compared to 16.7 minutes a day for the normal control group and just nine minutes a day for the controls with overweight/obesity.

Citing U.S. Office of Disease Prevention and Health Promotion (ODPHP) guidelines, Ostendorf said moderate-to-vigorous exercise is emphasized when it comes to maintaining weight loss. For example, the ODPHP recommends that weight-loss maintainers do 300 minutes of moderate-intensity aerobic activity (such as brisk walking, jogging, or swimming laps) each week compared to the 150 minutes of comparable activity for people in a normal weight range.

Benefits of light-intensity activities

The 300-minute guideline can be intimidating for people who are trying to maintain their weight loss, especially for those who struggle to exercise in a moderate to vigorous manner, Ostendorf said. “The fact that people may benefit from increasing light-intensity activities like doing household chores or taking the dog for a walk is encouraging information,” she said. “However, future weight loss interventions need to test whether increasing light-intensity activities can help people maintain weight loss.”

As part of her dissertation, Ostendorf plans to test the 300 minutes of moderate-intensity exercise guideline for weight-loss maintenance. She wonders if a lower amount of moderate-intensity activity, when coupled with less time being sedentary and more time doing light-intensity activity, would be just as effective in maintaining weight loss.

Track at the University of Colorado Anschutz Health and Wellness Center
A woman runs the track at the University of Colorado Anschutz Health and Wellness Center.

The potential exists, Ostendorf believes, to incorporate both reduced sedentary behavior and increased light-intensity activity into the ODPHP maintenance guidelines. “This would lead to future weight-loss interventions that people can do at the workplace, or at home because it involves physical activity that doesn’t require people to get their heart rate up, which can be uncomfortable for some people,” she said.

Not typically examined

Light-intensity activity is typically not examined in weight-loss maintenance studies because it’s more difficult to monitor than heart-pumping moderate-to-vigorous exercise. “Light-intensity activity is like walking in a grocery store – it’s movement, but it’s not really getting the heart rate up,” Ostendorf said.

She said workplace interventions, such as standing at your desk and taking more frequent breaks from sitting, can be beneficial to help break up dangerous sedentary behaviors. These easy-to-implement interventions would be helpful for health care professionals as they consult with patients about how to keep shed pounds from coming back.

“Understanding how people maintain weight loss is really important,” Ostendorf said. “If we can have an impact on helping people maintain their weight loss then we can help prevent chronic disease and early mortality. Excess weight is connected to so many disease pathways.”

 

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Obese and anorexic individuals react differently to taste

Researchers at the University of Colorado Anschutz Medical Campus have discovered that women suffering from anorexia nervosa and those who are obese respond differently to taste, a finding that could lead to new treatments for the eating disorders. 

 

“Taste is an important driver of food intake and invariably associated with distinct neuronal patters in the insula, the brain’s primary taste cortex,” said the study’s lead author Guido Frank, MD, a psychiatrist and associate professor at the CU School of Medicine.  

 

The study was recently published online in the International Journal of Eating Disorders.

Guido Frank, MD, associate professor of medicine and psychiatrist at the CU School of Medicine.

 

Frank and his team set out to find if abnormal eating patterns were associated with changes in the insula’s ability to classify taste stimuli. 

 

Some 106 women of similar age underwent brain imaging while tasting sugar water or a tasteless water solution. Researchers studied how well the insula could differentiate between the flavors.  

 

Individuals with anorexia nervosa or those who were obese, had difficulty distinguishing between ordinary water and sugar water, compared to control subjects and those who had recovered from anorexia nervosa.

 

“If you can’t differentiate between tastes, that could impact how much you eat,” Frank said. “That could also activate or not activate brain reward circuits.” 

 

These changes, he said, could occur on a variety of levels. For example, leptin and other hormones are altered in obesity and eating disorders, affecting how the brain responds to food. At the same time, the reduced ability of the insula to classify taste could be due to structural changes within this brain region or alternatively could result in altered taste signal processing in different pathways to the insula.

 

Research indicates that these problems diminish once a person reaches a healthy weight.

 

While more research is needed, Frank said one possible treatment could be to alter the taste of food. 

 

“Perhaps adjusting flavor intensity by reducing it for those with anorexia and enhancing it for those who are obese,” he said. “It’s something we need to examine more closely.” 

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