According to recent studies published in The Journal of Clinical Endocrinology & Metabolism, researchers are getting a better understanding of obesity and the continuing efforts to combat it. While the bad news is that there are a variety of side effects, the good news is that not all of the side effects are negative.
With rates of obesity in the U.S. remaining at staggeringly high levels, scientists are hard pressed to discover the most effective medical interventions to combat this disease. According to the Endocrine Society Facts and Figures Report on Obesity, 35.1% of U.S. adults are obese, defined as a body mass index (BMI) score of ≥30 kg/m2. That’s more than one in three adults who face any number of comorbidities, increased mortality, and reduced quality of life as well as increased risk of metabolic syndrome, which is itself a major risk for developing such chronic conditions as cardiovascular disease and diabetes. Worldwide, 13% of adults are obese, according to the World Health Association, but this number has nearly tripled in the last 40 years. In three studies published in The Journal of Clinical Endocrinology & Metabolism within the last six months, researchers take up arms against this mighty foe.
Mind Over Matter
In “Application of Mindfulness in a Tier 3 Obesity Service Improves Eating Behavior and Facilitates Successful Weight Loss,” the study’s first author, Petra Hanson, MBCHB, BSc, MRCP, AFHEA, a research fellow and PhD student at Warwickshire Institute for the Study of Diabetes Endocrinology and Metabolism at University Hospitals Coventry and Warwickshire, in Coventry, U.K., and team add mindfulness, the practice of fully attending to the present moment, to the armamentarium.
Given the success of the application of mindfulness in a wide variety of clinical contexts in the last 30 years, the team surmised that in patients with potentially problematic eating habits, becoming more aware of these harmful habits as well as more aware of what is being consumed could help patients lose weight and develop an overall healthier approach to food. To date, most weight-loss programs emphasize diet and exercise, and relapses among participants into former habits of poor food choices and low physical activity are rampant. Studies of mindfulness and weight loss, meanwhile, are scant.
“…mindfulness techniques can improve eating behavior and facilitate weight loss in patients with obesity attending specialist weight management services. Mindfulness taught in such a setting can also improve patients’ confidence and ability to manage weight in the long term. It is a very scalable intervention that can be applied to everyone.” – Petra Hanson, MBCHB, BSc, MRCP, AFHEA, research fellow, PhD student, Warwickshire Institute for the Study of Diabetes Endocrinology and Metabolism, University Hospitals Coventry and Warwickshire, Coventry, U.K.
The team recruited 53 participants with a BMI >35Kg/m2 and age >18 years to attend four 90-minute group sessions every two weeks for eight weeks at a Warwickshire weight management clinic, 33 of whom completed the series. The focus of the series was on behavior change rather than weight loss, and, as such, training sessions in mindfulness techniques were offered as part of the overall approach. Strategies taught included how to eat mindfully rather than mindlessly in addition to how to practice self-compassion — avoiding excessive self-criticism and instead invoking self-confidence to overcome health barriers.
Participants provided self-reported eating behavior and body weight at the start of the trial and again on completion. After six months, participants who completed the mindfulness training series had lost an average of 6.7 pounds, as compared to about two pounds among the patients who skipped two or more sessions. A retrospective control group comprised 33 participants who attended the group sessions but were not taught how to implement mindfulness techniques; these patients received what is considered “standard care” at the clinic currently and lost significantly less weight on average — about half a pound. Notably, the program’s focus on behavior change also produced favorable results, as participants demonstrated significantly less “fast foodism,” which the researchers define as eating considerably more fast food than fresh food.
“Our study has shown that mindfulness techniques can improve eating behavior and facilitate weight loss in patients with obesity attending specialist weight management services,” Hanson says. “Mindfulness taught in such a setting can also improve patients’ confidence and ability to manage weight in the long term. It is a very scalable intervention that can be applied to everyone.”
Bypass Surgery Flexes Its Muscles
A second study uncovers previously unknown benefits of a common weight-loss surgical procedure. Roux-en-Y gastric bypass (RYGB) surgery anastomoses a small, egg-sized part of the stomach directly to the jejunum so that most of the stomach and the duodenum are bypassed when food is eaten. Thus, the new stomach can hold a considerably smaller amount of food, and considerably less fat is absorbed with the duodenum out of the picture. For extremely obese patients (BMI ≥40 kg/mg2) and obese patients with serious comorbidity, such bariatric surgery procedures promise substantial weight loss as well as reduction of obesity-related risk factors and comorbidities. A purported side effect, however, is that patients experience a potentially detrimental and ongoing loss of muscle that can result in long-term skeletal muscle insufficiency, metabolic impairment, and the inability to maintain a physically active lifestyle.
The new study finds that the impact of RYGB on muscle may be misunderstood, however. In “Changes in Lean Mass, Absolute and Relative Muscle Strength, and Physical Performance After Gastric Bypass Surgery,” Diana Alba, MD, of the University of California in San Francisco, and team took baseline measurements of fat versus lean mass, handgrip strength, and physical activity and performance (indicated by chair stand time, gait speed, and 400-meter walk time, tests that are valid, reliable, and sensitive to change) in 47 study participants about to undergo RYGB with BMI 44 ± 8 kg/m2. They measured changes in these indices at six and 12 months post RYGB.
At 12 months preoperatively, all participants had lost a significant amount of weight, a mean of 30% ± 7%. Absolute muscle strength decreased at a mean of 2.6 ± 5.4 kg, a rate that was driven by women versus men; however, relative muscle strength, defined as absolute handgrip strength/BMI and as absolute strength/appendicular lean mass (ALM) — also known as “muscle quality,” progressively increased after 12 months, as did gait speed, while time to complete five chair stands and to walk 400 meters decreased in both biologic sexes.
Notably, body composition changes were steepest in the first six months postoperatively, and researchers posit that early interventions, such as perioperative and postoperative resistance training exercises, might help to maintain lean mass, improve quality of life, and avoid long-term disability.
The upshot is, according to Alba, “Besides reducing body weight and obesity-associated comorbidities and mortality, RYGB significantly improves a person’s relative muscle strength and physical performance.” The improvement in physical performance is perhaps due to biomechanical changes that RYGB brings about. Although the decline in absolute muscle strength that is a known side effect of bariatric surgery is therefore an incomplete picture, strategies to address the associated loss of lean mass should be part of ongoing research.
Health Benefits of Weight Cycling Outweigh Adverse Effects in Obesity
In the third study, the news is not all good — neither is it all bad, and we’ll take it. To get the bad news out of the way first, of the millions of people every day who start a diet to lose weight, only a small percentage succeed in keeping the weight off one to five years later. This is at least partly due to the typical diet and feast response, in which the dieter regains the weight lost if not more, then starts another diet — weight cycling. Some blame psychology as the basis underpinning the cycle, that hinges on the negative feelings the dieter experiences — deprivation from food restriction, shame, and disappointment from giving in to the increased desire for tempting foods. To relieve the negative feelings, the dieter eats even more, and the cycle begins anew. But there is undeniably a biochemical explanation to body-weight fluctuation as well. When weight is lost, hunger hormones like ghrelin kick in, while satiety hormones like leptin take a back seat. In addition to this homeostatic feedback mechanism, fat cells are programmed to maintain their size and will overstore fat to reverse any shrinkage.
“Besides reducing body weight and obesity-associated comorbidities and mortality, RYGB significantly improves a person’s relative muscle strength and physical performance.” – Diana Alba, MD, University of California in San Francisco
As despairing as this tale of woe is, the health repercussions can be downright tragic. In “Body-Weight Fluctuation and Incident Diabetes Mellitus, Cardiovascular Disease, and Mortality: A 16-Year Prospective Cohort Study,” Hak C. Jang, MD, PhD, professor, Seoul National University College of Medicine and Seoul National University Bundang Hospital in Seongnam, South Korea, and team suggest that weight-cycling actually produces harmful changes in body composition by exchanging lean mass for fat mass. As they show, fat mass is reduced more than lean mass during dieting, but lean mass does not increase as much as fat mass when weight is regained.
The team collected health-related outcomes every two years for 16 years in 3,678 Korean participants from the Korean Genome and Epidemiology Study, designed to evaluate noncommunicable disease and related risk factors. “In the 16-year prospective cohort study, we found higher weight cycling was associated with increased risk of all-cause mortality,” Jang says.
An individual’s body-weight fluctuations were calculated by “average successive variability (ASV),” and those with a high ASV of body weight were more obese, had higher blood pressure levels, and demonstrated increased insulin resistance at baseline than those with a low ASV of body weight. A one-unit increase in ASV of body weight was associated with increased mortality in participants with high cardiovascular risk as well as in healthy participants.
As for diabetes mellitus risk, and this is where the news gets a bit brighter, that depended on both the presence of obesity and the degree of bodyweight changes. Diabetes was positively associated with the ASV of body weight in the subgroup whose baseline BMI was <25 kg/m2, but negatively associated in subjects with BMI ≥25 kg/m2.
“People with obesity who experienced more weight cycling were less likely to develop diabetes,” Jang says. Thus, for obese participants, the beneficial effect of losing weight on diabetes prevention may outweigh the adverse effects of weight cycling.
-Horvath is a freelance writer based in Baltimore, Md. She wrote about thyroid cancer and heart disease in the February issue.
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