At the recent European Congress on Obesity, I had the occasion for a long chat with my friend and colleague Abdul Dulloo, from Friburg in Switzerland, who has worked extensively on the issue of weight regain.
I asked him how much evidence there is to support the common notion that losing weight makes you fatter – something many dieters claim to have experienced.
Indeed, both in animals and humans, weight loss, as a rule, is followed by a more rapid regain of body fat than lean body mass (i.e. preferential catch-up fat) than of lean body mass, as a result of which body composition post-weight regain results in a greater proportion of fat mass than before. But does this increased “fatness” persist over time?
This is where Dulloo made me aware of a recent paper he published in Obesity Reviews that examines this question.
What his analysis of prospective studies on this issue revealed is that paradoxically, people within a the normal weight range appear much more prone to weight gain over time with dieting than people who already have overweight or obesity.
Indeed as he points out,
“…it is dieting to lose weight in people who are in the healthy normal range of body weight, rather than in those who are overweight or obese, that most strongly and consistently predict future weight gain.”
The reasons for this rather unexpected finding are unclear and some have argued that repeated dieting to lose weight in normalweight people may represents unsuccessful attempts to counter genetic and familial predispositions to obesity – these people are genetically prone to weight gain, which is why they are dieting in the first place. Thus, rather than a causal relationship, the association between dieting and subsequent weight gain is just what would have happened to them anyway.
Others have argued that the metabolic effects resulting from the psychological “fear of fatness” (which prompts dieting) per se may increase the risk for weight gain hence a contributing factor to the obesity epidemic.
However, as Dulloo and colleagues discuss at length, based on their reanalysis of a wide range of human studies of weight loss and refeeding on body composition data on fat mass and fat-free mass (FFM) losses and regains, there is increasing support for the biological plausibility that dieting predisposes lean individuals (rather than those with overweight or obesity) to regaining more body fat than what had been lost (i.e. fat overshooting).
Overall the findings suggest that perhaps the reason why lean people regain fat faster is because their feedback signals in response to the depletion of both fat mass (i.e. adipostats) and fat-free mass (i.e. proteinstats), through the modulation of energy intake and adaptive thermogenesis, are more effective than in individuals with overweight or obesity, thus resulting in a faster rate of fat recovery relative to recovery of lean tissue (i.e. preferential catch-up fat).
In fact, it appears that lean people overshoot in terms of weight gain because the state of hyperphagia (in response to weight loss) appears to persist well beyond complete recovery of fat mass and interestingly until fat free mass is fully recovered (which may take months during which time fat gain continues).
Thus, it appears that in lean individuals “fat overshooting” following a diet is a prerequisite to allow complete recovery of fat-free mass (in obese individuals this may be less of an issue as recovery of fat-free mass is stimulated simply by the need to carry around a greater body weight).
Thus, it is easy to understand why repeated dieting and weight cycling would increase the risks for trajectories from leanness to fatness particularly in people who have a normal weight to begin with.
These findings have important public health implications and for promoting a “fear of fat”.
As Dulloo notes,
“Given the increasing prevalence of dieting in normal-weight female and male among young adults, adolescents and even children who perceive themselves as too fat (due to media, family and societal pressures), together with the high prevalence of dieting for optimizing performance among athletes in weight-sensitive sports, the notion that dieting and weight cycling may be predisposing a substantial proportion of the population to weight gain and obesity deserves greater scientific scrutiny.”
Indeed, I wonder how much of the obesity epidemic is directly attributable to normal weight people trying to lose weight for no good reason other than to look better.
Dulloo AG, Jacquet J, Montani JP, & Schutz Y (2015). How dieting makes the lean fatter: from a perspective of body composition autoregulation through adipostats and proteinstats awaiting discovery. Obesity reviews : an official journal of the International Association for the Study of Obesity, 16 Suppl 1, 25-35 PMID: 25614201
This morning, I am presenting a talk at a workshop hosted by the Ontario Public Health Association’s Nutrition Resource Centre here at the 4th Canadian Obesity Summit in Toronto.
As the organisers of the symposium point out,
“Messages from the media, industry, and even some health professionals and public health campaigns often convey the idea that obesity can be prevented by simply eating less, eating better, and moving more. This reinforces the idea that obesity is a matter of lifestyle choices and personal responsibility. However, is obesity prevention really that simple? What about the role of the food environment and social determinants of health? Are current messages about obesity actually effective? Is it as easy as “eat less, eat better”?”
This one-day forum, brings together Canadian health promotion and nutrition professionals to explore the answers to these timely questions. Through (hopefully) thought-provoking presentations and engagement with leading experts, participants will be challenged to critically rethink conventional approaches to healthy eating and obesity messaging.
Indeed, the fact that many working in public health and obesity prevention are revisiting the often-heard messaging about simply eating less and moving more as a means of achieving a “healthy” weight, is a big step forward in perhaps coming closer to finding an effective communication and messaging strategy about obesity that does not inadvertently promote simplistic notions about obesity that do little else than reinforce and propagate weight bias.
I congratulate the OPHA’s Nutrition Resource Centre for taking on this challenge and opening, what I am sure will be a most fruitful dialogue, that will eventually change both the perception of what obesity actually is and lead to solutions that both incorporate our latest understanding of this complex chronic disease and do so without unintended harm to those living with this condition.
If you are planning to attend the 4th Canadian Obesity Summit in Toronto next week (and anyone else, who is interested), you can now download the program app on your mobile, tablet, laptop, desktop, eReader, or anywhere else – the app works on all major platforms and operating systems, even works offline.
You can access and download the app here.
(To watch a brief video on how to install this app on your device click here)
You can then create an individual profile (including photo) and a personalised day-by-day schedule.
Obviously, you can also search by speakers, topics, categories, and other criteria.
Hoping to see you at the Summit next week – have a great weekend!
Regular readers will be well of the very real social and health impact of weight bias and discrimination.
Now, Sara Kirk of Dalhousie University, Halifax, NS, invites you to join her free Massive Open Online Course (MOOC), on weight bias and stigma in obesity, which will be starting on April 20th 2015 (just a week before the Canadian Obesity Summit in Toronto).
The course builds on Kirk’s extensive research in this area and the dramatic presentation that was created from her findings.
Participants will be able to explore some of the personal and professional biases that surround weight management and that impact patient care and experience.
This will hopefully give health professionals better insight into how to approach individuals experiencing obesity in a respectful and non-judgmental manner and provide strategies to build positive and supportive relationships between health care providers and patients.
While targeted at health care providers, the course should also be of interest to anyone interested in learning more about what weight bias is and how it can impact health and relationships.
Participants who complete the course requirements can apply for a citation of completion (for a nominal fee).
Today I will be attending a Summit on Weight Bias at the University of Calgary, that will explore the the issue of weight-based discrimination and ways to address this – especially in health care settings.
It should come as no surprise that weight bias and discrimination are a major barrier to providing proper preventive and therapeutic health care due to the widespread attitudes and beliefs about obesity that exist amongst health professionals and decision makers.
The scientific summit, co-sponsored by the Canadian Obesity Network, Campus Alberta, and the Canadian Institutes of Health Research (CIHR), is complemented by a public Cafe Scientifique that will be held on Thursday, March 12, 7.00 at the Parkdale Community Association, 3512 – 5 Ave NW, in Calgary.
For more information and pre-registration for this free public event, which features
Leora Pinhas, MD
Child & Adolescent Psychiatrist, Physician Lead, Eating Disorders Unit, Ontario Shores Centre for Mental Health Sciences Assistant Professor, University of Toronto
Tavis Campbell, PhD
Professor, Department of Psychology and Oncology & Director, Behavioural Medicine Laboratory, University of Calgary
Yoni Freedhoff, MD, CCFP
Medical Director, Bariatric Medical Institute, Assistant Professor, University of Ottawa