On the last day of the 8th Annual Obesity Symposium here in Norderstedt, Germany, Marco Bueter from the University of Zurich presented a fascinating series of studies (just published in Circulation), demonstrating the “weight-independent” benefits of gastric bypass surgery on endothelial function (using an animal model).
Besides showing that 8 days after bypass surgery rats with diet-induced obesity had higher plasma levels of bile acids and GLP-1, that were associated with improved endothelium-dependent relaxation, not seen in sham-operated weight matched controls, but also that these effects could be prevented by blocking GLP-1 receptors with exendin 9-39.
In contrast, similar effects to those seen on vascular function in bypass rats were seen in sham-operated rats treated for 8 days with the GLP-1 analogue, liraglutide, or as the authors describe it,
“liraglutide restored NO bioavailability and improved endothelium-dependent relaxations and HDL endothelium-protective properties, mimicking the effects of RYGB”
Together these studies suggest that GLP-1 may well play an important causal role in the improved vascular function seen in patients undergoing gastric bypass surgery.
These findings are all the more interesting as liraglutide has now been approved for obesity treatment in the USA, Canada and Europe.
While these data are certainly not enough to describe liraglutide as “surgery in a pen”, they are indeed promising in terms of potential benefits of this treatment that may well be weight independent.
All the more reason to anticipate the outcome of the ongoing LEADER trial, which is currently evaluating the effect of liraglutide treatment on cardiovascular outcomes in patients with type 2 diabetes.
Disclaimer: I have served as a paid consultant and speaker for Novo Nordisk, the maker of liraglutide.
Over the past few months, I have been working with mdBriefCase, a major provider of free online accredited continuing medical education, to produce interactive modules for obesity management.
The modules are aimed at practitioners working in primary care and pharmacists and align closely with the Canadian Obesity Network’s 5As of Obesity Management framework.
The accredited course (Mainpro M1 and MOC Section 1 or 3 credits) is available free of charge to all Canadian Health Professionals.
To access the course for physicians and allied health practitioners on mdBriefCase – click here
To access the course for pharmacists on rxBriefCase – click here
I have long postulated that the benefits of exercise in weight management have little to do with burning calories. Rather, I am pretty sure that when people lose weight with exercise, they do so because of the impact that exercise may have on their food intake (I call it exercising to ruin your appetite!).
Thus, I am happy to acknowledge my affirmation bias in paosting about the recent study by Larissa Ledochowski and colleagues from the University of Innsbruck, Austria, published in PLOS One on the outcome of a randomised controlled trial of brisk walking on cravings for sugary snacks.
The study was conducted in 47 overweight volunteers who reported habitually consuming a fair share of sugary snacks. Following 3 days of “chocolate abstinence” subjects were randomised (using a within-subject design) to a 15-min brisk walk or passive control.
On each occasion, subjects were then stressed using the Stroop color–word interference task after which they reported their urges for sugary snacks using the State Food Craving Questionnaire [FCQ-S] adapted for sugary snacks.
Compared to the control situation, brisk walking resulted in a significant and relevant reduction in the urge for sugary snacks and attenuated the increase in sugar-cravings under trigger conditions (stress).
Although the authors are careful about not over-interpreting their findings from this acute study (that did not actually measure sugary-snack intake), they do make the following speculation regarding clinical relevance,
“This study adds to the increasing evidence that physical activity can somehow help to regulate the urge to consume snack food. It may be easy for overweight people to fit in short bouts of low-moderate intensity physical activity, instead of being sedentary, to elevate affective activation and valence and reduce high energy food cravings which may be triggered by stress and the presence of snack foods.”
While I am certain that more intense exercise may well trigger a hunger response, it appears that even a short bout of brisk walking may help dispel those cravings for sugary snacks (let me know if you have experienced this).
Now a study by Jennifer Fenn and colleagues from the University of Vermont report significant weight gain with methadone treatment for opioid addiction in a paper published in the Journal of Substance Abuse Treatment.
The retrospective chart review included 96 patients enrolled in an outpatient methadone clinic for ≥ 6 months.
Overall mean BMIs increased by about 3 units (from 27.2 to 30.1), which corresponds roughly to an 18 lb or 10% increase in body weight.
Interestingly, the weight gain was predominantly seen in women, who gained about 28 lbs or 17.5% body weight compared to men, who only increased their weight by about 12 lbs or 6.4%.
As the study did not have access to food records, one can only speculate as to the causes. While better nutrition may well play a role, one could also speculate that there may be some addiction transfer from opioids to calorie-dense foods.
Whatever the cause, clinicians should probably be aware of this potential impact of methadone treatment on body weight, as prevention of excess weight gain may be easier than treating obesity once it is established.
Now, Mary Boggiano and colleagues from the University of Birmingham, Alabama, in a paper published in Appetite, report that using tasty foods as a coping strategy is associated with weight gain.
The study administered the Palatable Eating Motives Scale (PEMS), which assesses eating for coping motives (e.g., to forget about problems, reduce negative feelings), to 192 college students, who were reexamined after two years (with a few measures in between).
Not too surprisingly, PEMS scores predict changes in BMI over two years.
On a positive note, however, the researchers found that PEMS scores (i.e. using food for coping) can change over time and a reduction in PEMS scores was also associated with a lesser weight gain. In overweight subjects, a reduction in PEMS scores was even associated with modest weight loss.
Thus, the authors suggest that interventions aimed specifically at reducing palatable food intake for coping reasons, should help prevent obesity if this motive-type is identified prior to significant weight gain.