Tuesday, September 16, 2014

Is Food Addiction Better Described As Eating Addiction?

sharma-obesity-addiction-typesThe term “food addiction” has found its way into both the scientific and popular literature.

Now, a thoughtful paper by Johannes Hebebrand and colleagues, published in Neuroscience & Biobehavioral Reviews, argues that there is in fact little evidence for addiction to “food” per se (as you would see in addiction to a specific substance) and that therefore, it may be better to describe the addiction-like overconsumption of food as a behavioural addiction, in this case, an addiction to eating.

Eating is intrinsically rewarding and reinforcing, and food consumption is well-known to activate the reward system in the brain; this applies particularly in the physiological state of hunger. It is easy to see that the rewarding properties of food and their activation of the reward pathway might lead intuitively to the idea that food substances may have addictive properties. However, just because eating behavior engages these reward systems, it does not necessarily follow that specific nutrients (substances) are able to evoke a substance addiction. Instead, the complex activation of the reward system as the initial step of the process ending in addiction can be viewed as being dependent on eating (subjectively) palatable foods irrespective of their nutritional/chemical composition.”

Per se, foods are nutritionally complex and there is hardly any evidence to suggest that under normal physiological circumstances humans crave specific foods in order to ingest a specific ‘substance’. Instead, the diet of subjects who overeat typically contains a broad range of different, subjectively palatable foods. It can be argued that access to a diversity of foods, especially a diverse range of palatable foods, may be a pre-requisite for the development of addictive-like eating behavior.”

There is currently no evidence that single nutritional substances can elicit a Substance Use Disorder in humans according to DSM 5 criteria. In light of the lack of clinical studies that have aimed to detect addictions to specific nutrients, it cannot as yet be ruled out that a predisposed subgroup does indeed develop such a substance based addiction, which in theory may be substantially weaker than in the case of addictions based on well-known exogenous substances such as alcohol, cannabis, nicotine or opiates. The fact, that clinical case studies do not abound on an addiction like intake of specific nutrients or even specific foods, would suggest that such cases are rare, if they exist at all. Alternatively, the addiction is so weak that it is not adequately perceived and reported as such. This leads to the question as to the boundaries between excessive consumption and the beginning of a true addiction.”

Thus,

“…there is very little evidence to indicate that humans can develop a “Glucose/Sucrose/Fructose Use Disorder” as a diagnosis within the DSM-5 category Substance Use Disorders. We do, however, view both rodent and human data as consistent with the existence of addictive eating behavior. The novel DSM-5 (APA, 2013) currently does not allow the classification of an “Overeating Disorder” or an “Addictive Eating Disorder” within the diagnostic category Substance-Related and Addictive Disorders; indeed, the current knowledge of addictive eating behaviors does not warrant such a diagnosis. However, efforts should be made to operationalize the diagnostic criteria for such a disorder and to test its reliability and validity. It needs to be determined if such a disorder can occur distinct from other mental disorders.”

Overall I believe that reframing the perceived loss of control over food intake often reported by my patients as a “behavioural” rather than a “substance” addiction may be helpful in approaching this rather complex topic and may well open the path to novel therapeutic approaches more consistent with our current understanding of behavioural addictions.

@DrSharma
Vienna, Austria

ResearchBlogging.orgHebebrand J, Albayrak O, Adan R, Antel J, Dieguez C, de Jong J, Leng G, Menzies J, Mercer JG, Murphy M, van der Plasse G, & Dickson SL (2014). “Eating addiction”, rather than “food addiction”, better captures addictive-like eating behavior. Neuroscience and biobehavioral reviews PMID: 25205078

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Friday, August 29, 2014

2014 Scopinaro Lecture

Nicola Scopinaro, MD, Professor of Surgery, University of Genoa Medical School, Italy

Nicola Scopinaro, MD, Professor of Surgery, University of Genoa Medical School, Italy

This morning, at the XIX World Congress of the International Federation of Surgery for Obesity and Metabolic Disorders (IFSO2014), I have the great honour of presenting the 2014 Scopinaro Lecture.

This lecture is named after Nicola Scopinaro, who in 1976 performed the first biliopancreatic diversion for the treatment of obesity.

The Scopinaro Lecture is the highest recognition for a non-surgeon to be awarded by IFSO.

In thinking about what to present, I settled on discussing the topic of whether or not obesity is a disease. Looking back over the work that I have done over the past 25 years, I came to realise that the issue of why some people with excess weight develop health problems and others don’t, has indeed fascinated me for a long time.

Initially, this interest was focussed on trying to understand why some people with obesity develop high blood pressure and others don’t. We were indeed able to show that part of this may be explained by differences in the expression of hormones involved in blood pressure regulation from fat tissue.

More recently, as many regular readers are well aware, I have broadened this interest in describing the limitations of BMI and advocating for a clinical staging system that classifies overweight and obese individuals based on how “sick” they are rather than how “big” they are.

Clearly, this work is of considerable interest to those involved in bariatric care (including bariatric surgeons), as it provides a framework for better prioritizing and assessing risk/benefit ratios than BMI or other anthropometric measures alone.

As I point out in my talk,

- The etiology of obesity is complex and multifactorial.

- The physiology of energy regulation is complex and subverts volitional attempts at weight loss.

- Access to obesity prevention and treatments must be driven by the recognised medical needs to address this condition.

- Multidisciplinary management of this life-long disorder requires resources similar to those required for other chronic diseases

In receiving this honour, I am fully aware that all of my work stands on the shoulders of the many researchers and clinicians who came before me and the considerable support and help that I have been fortunate enough to receive from my many students, trainees, colleagues and supervisors.

This award will certainly serve an a strong incentive to continue my work and advocacy for better treatments for obesity and the advancement of bariatric care.

@DrSharma
Montreal, QC

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Thursday, August 28, 2014

Call For Abstracts: Canadian Obesity Summit, Toronto, April 28-May 2, 2015

COS2015 toronto callBuilding on the resounding success of Kananaskis, Montreal and Vancouver, the biennial Canadian Obesity Summit is now setting its sights on Toronto.

If you have a professional interest in obesity, it’s your #1 destination for learning, sharing and networking with experts from across Canada around the world.

In 2015, the Canadian Obesity Network (CON-RCO) and the Canadian Association of Bariatric Physicians and Surgeons (CABPS) are combining resources to hold their scientific meetings under one roof.

The 4th Canadian Obesity Summit (#COS2015) will provide the latest information on obesity research, prevention and management to scientists, health care practitioners, policy makers, partner organizations and industry stakeholders working to reduce the social, mental and physical burden of obesity on Canadians.

The COS 2015 program will include plenary presentations, original scientific oral and poster presentations, interactive workshops and a large exhibit hall. Most importantly, COS 2015 will provide ample opportunity for networking and knowledge exchange for anyone with a professional interest in this field.

Abstract submission is now open – click here

Key Dates

  • Abstract submission deadline: October 23, 2014
  • Notification of abstract review: January 8, 2014
  • Early registration deadline: March 5, 2015

For exhibitor and sponsorship information – click here

To join the Canadian Obesity Network – click here

I look forward to seeing you in Toronto next year!

@DrSharma
Montreal, QC

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Wednesday, August 27, 2014

XIX World Congress on Obesity Surgery, Montreal

ifso14 logoFor the rest of this week I will be reporting from the XIX World Congress of the International Federation for the Surgery of Obesity and Metabolic Disorders (IFSO) here in Montreal, Canada.

Although I am not a surgeon, staying up to date on all aspects of bariatric surgery is essential for anyone working in the field of bariatric care – and advances there are.

But I am not just here to listen. This morning, together with my colleague Sean Wharton, I will be presenting a 4 hour masters course on obesity management for allied health professionals and later today, I will be presenting a talk on the use of the Edmonton Obesity Staging System as a better way to determine the risk and prognosis of bariatric patients.

I certainly look forward to an intense week of learning and networking in this wonderful city.

@DrSharma
Montreal, QC

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Friday, August 8, 2014

Healthy Obesity: More Questions Than Answers?

sharma-obesity-visceral-fat-mriRegular readers will be well aware of the evidence that a subset of people living with obesity can be remarkably healthy despite carrying a rather large amount of body fat.

This issue of “healthy obesity” was the topic of the 13th Stock Conference of the International Association of the Study of Obesity, the proceeding of which are now published in Obesity Reviews.

As the authors note,

“The ‘healthy obese’ phenotype was described in the 1980s, but major advancements in its characterization were only made in the past five years. During this time, several new mechanisms that may be involved in health preservation in obesity were proposed through the use of transgenic animal models, use of sophisticated imaging techniques and in vivo measurements of insulin sensitivity. However, the main obstacle in advancing our understanding of the metabolically healthy obese phenotype and its related long-term health risks is the lack of a standardized definition.”

The latter is a real problem because finding people with obesity, who are truly metabolically and otherwise healthy becomes harder the higher the BMI gets – this makes the study of this phenomenon rather challenging.

Nevertheless,

“One of the most consistent characteristics of metabolic health in obesity across studies in humans is reduced liver lipid. This is likely the consequence of increased capacity for storing fat coupled with improved mitochondrial function in adipose tissue and decreased de novo lipogenesis in liver. This can also result in decreased deposition of lipids, including bioactive species, in skeletal muscle. Decreased adipose tissue inflammation with decreased macrophages and a unique T-cell signature with an anti-inflammatory circulating milieu were also suggested to characterize metabolic health in obesity. Anecdotal data support a possible role for healthier lifestyle, including increased level of physical activity and healthier diet. It remains to be established whether a favourable metagenomic signature is a characteristic of metabolic health in obesity.”

Finland’s, Dr Kirsi Pietiläinen explained that,

“..three energy dissipation pathways, oxidative phosphorylation, fat oxidation and amino acid catabolism showed preserved pathway activities in subjects who are MHO at a level similar to their lean counterparts. In contrast, these pathways were significantly down-regulated in adipose samples from obese twins with metabolic disturbances. Another potential hallmark of metabolic health, a favourable inflammatory profile of the adipose tissue was also observed in the MHO twins. Also, the fat cells of the MHO twins were smaller with evidence of more active differentiation processes within the fat tissue. As multiple mitochondrial pathways are vital in adipocyte differentiation [29], it is possible that mitochondrial malfunction impairs the development of new fat cells, which in turn results in an inability of the adipose tissue to expand under conditions of energy excess. This failure of fat cell proliferation has long been suspected to constitute the framework for ectopic fat storage, insulin resistance and type 2 diabetes.”

Other speakers discussed other aspects including immune function and microbiata in this phenomenon.

Finally, the authors concluded that,

“identifying underlying factors and mechanisms associated with this phenotype will eventually be invaluable in helping the scientific and medical community understand factors that predispose, delay or protect obese individuals from metabolic disturbances. It is essential to underscore that the MHO concept presently only address the cardio-metabolic risks associated with obesity; it is therefore important that patients who are MHO are still very likely to present many other obesity-related complications such as altered physical and/or physiological functional status, sleep problems, articulation and postural problems, stigma, etc. Importantly, the MHO concept supports the fact that classification based on excess adiposity per se (e.g. BMI or body composition if available) should be supplemented with obesity-related comorbidities, e.g. with fasting insulin as proposed by the Edmonton obesity classification system.”

Certainly a space to watch as we learn more and more about the “healthy obesity” phenotype.

@DrSharma
Edmonton, AB

ResearchBlogging.orgSamocha-Bonet D, Dixit VD, Kahn CR, Leibel RL, Lin X, Nieuwdorp M, Pietiläinen KH, Rabasa-Lhoret R, Roden M, Scherer PE, Klein S, & Ravussin E (2014). Metabolically healthy and unhealthy obese – the 2013 Stock Conference report. Obesity reviews : an official journal of the International Association for the Study of Obesity PMID: 25059108

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In The News

Diabetics in most need of bariatric surgery, university study finds

Oct. 18, 2013 – Ottawa Citizen: "Encouraging more men to consider bariatric surgery is also important, since it's the best treatment and can stop diabetic patients from needing insulin, said Dr. Arya Sharma, chair in obesity research and management at the University of Alberta." Read article

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