This fallacy is based on the rathe simplistic notion that because 7 x 500 arithmetically happens to equal 3,500 Cal, which just happens to be approximately the caloric content of 1 lb of fat tissue, a reduction in weekly energy intake of 3,500 calories should lead to a 1 lb weight loss.
Thus, a recent rather unfortunate “Patient Information” page published in JAMA, states that,
“A total of 3500 calories equals 1 pound of body weight. This means if you decrease (or increase) your intake by 500 calories daily, you will lose (or gain) 1 pound per week. (500 calories per day × 7 days = 3500 calories.)”
Nothing could be further from the truth!
Now David Allison and colleagues, in a letter to the JAMA editors, points out just how nonsensical this “rule” actually is:
“For example, if a 5′6″, 30-year-old woman weighing 180 lb and consuming 2622 calories daily reduced her intake by 500 calories per day, the 3500-calorie rule would estimate her weight loss at 1 year to be almost 52 lb. At 10 years, the 3500-calorie rule would yield a negative body weight..”
Or, as I tell my patients, no one will continue losing weight till they disappear.
As regular reader of these page will appreciate, the simple reason why the 3500 Cal rule is wrong, is because the relationship between changes in caloric intake and weight loss is anything but linear. Rather, as daily caloric consumption decreases (or increases), metabolic demands adapt to compensate for this decrease (or increase), thereby limiting what happens to body weight.
This “dynamic” model of weight loss is nicely illustrated in the many validated predictors of weight loss available online (click here for an example).
Thus, based on such a model, in the above case, the actual expected weight loss at 1 year would only be around 12 lb with stabilization of a a 31-lb loss after 3 years.
Incidentally, these number, which in the above case correspond to about a 7% weight loss at one year and a 16% weight loss at 3 years are well in excess of what can generally be achieved with diet and exercise alone (those numbers being closer to 3-5% at 12-24 months).
As Allison and colleagues rightly point out, such inaccuracies (especially when propagated by reputable journals such as JAMA) mislead both health professionals and the public and do little more than promote unrealistic expectations about weight loss.
It is high time we abandoned simplistic “energy-in energy-out” models of obesity or weight management.
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
- Notification of abstract review: January 8, 2015
- Call for late breaking abstracts open: Jan 12-30, 2015
- Notification of late breaking abstracts and handouts and slides due : Feb 27, 2015
- Early registration deadline: March 3, 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!
Over the next three days, I will be in Waterloo, Ontario, attending the 4th biennial Canadian Obesity Student Meeting (COSM 2014), a rather unique capacity building event organised by the Canadian Obesity Network’s Students and New Professionals (CON-SNP).
CON-SNP consist of an extensive network within CON, comprising of over 1000 trainees organised in about 30 chapters at universities and colleges across Canada.
Students and trainees in this network come from a wide range of backgrounds and span faculties and research interests as diverse as molecular genetics and public health, kinesiology and bariatric surgery, education and marketing, or energy metabolism and ingestive behaviour.
Over the past eight years, since the 1st COSM was hosted by laval university in Quebec, these meetings have been attended by over 600 students, most presenting their original research work, often for the first time to an audience of peers.
Indeed, it is the peer-led nature of this meeting that makes it so unique. COSM is entirely organised by CON-SNP – the students select the site, book the venues, review the abstracts, design the program, chair the sessions, and lead the discussions.
Although a few senior faculty are invited, they are largely observers, at best participating in discussions and giving the odd plenary lecture. But 85% of the program is delivered by the trainees themselves.
Apart from the sheer pleasure of sharing in the excitement of the participants, it has been particularly rewarding to follow the careers of many of the trainees who attended the first COSMs – many now themselves hold faculty positions and have trainees of their own.
As my readers are well aware, I regularly attend professional meetings around the world – none match the excitement and intensity of COSM.
I look forward to another succesful meeting as we continue to build the next generation of Canadian obesity researchers, health professionals and policy makers.
You can follow live tweets from this meeting at #COSM2014
In my final instalment of commentaries on the right-wing Fraser Institute’s report claiming that obesity is overstated and that Governments may best stay out of trying to tackle this problem (except perhaps to provide treatments to those with more severe obesity), here are the arguments that the report puts forward favouring private solutions.
“First, there is a market test for private solutions where products and services that fail to meet their promises or customer expectations will cease to be provided. This is quite different from government interventions that do not need to meet such a test and thus may continue even if they have failed to produce the desired results in practice. Government interventions may in fact become more stringent and interventionist over time in response to their failings.”
“Second, private companies will continue to innovate and experiment in an effort to best meet the needs and desires of consumers in a cost-effective way. This is very much unlike government interventions, which are often precsriptive and constrain innovation. The result is that private organizations are more likely to find effective and less costly solutions for individuals, and are better able to adjust to changing information and knowledge, and changing consumer preferences over time.”
“Third, private initiatives do not impose a cost on the non-obese generally. This is very much unlike government initiatives that impact both the obese and the non-obese, for example through reduced options/choices, increased travel time, increased costs from taxation, increased costs of goods and services as a result of regulation, or taxpayer-funding of programs.”
While each of the above may carry some merit or are at least worth discussing, the final paragraph in this section reeks of considerable and unacceptable weight bias:
“Finally, and perhaps most critically, it is likely that most obese individuals realize they are heavy and that they may be making diet and lifestyle choices that keep them obese. They also have strong reasons to drop their excess weight including social stigma, reduced incomes, and the health risks associated with the excess weight. As Marlow and Abdukadirov note, “[the obese] hardly need the government to give them additional incentives to lose weight. People aware of their mistakes also have strong incentives to correct them.”
This rather abhorrently worded paragraph reflect all that is wrong with most public discussions on obesity – irrespective of political ideology – namely the notion that obesity is largely a matter of choice and that excess weight is something people can simply chose to drop if only they so chose by giving up their “mistakes”.
It is in this single paragraph that essentially makes the entire report largely irrelevant, as it is evident that the authors themselves struggle with fully understanding the actual nature of the problem they are trying to address.
Indeed, the whole tenor of individual “responsibility” interwoven with the language of “shame and blame” shows virtually no understanding of the real causes of the obesity epidemic or of the complex biology that people challenged by this problem face in trying to control their weight.
So, while we may quibble about whether or not the government is the best institution to tackle obesity or not, no meaningful discussion of solutions to the problem are possible unless we go beyond blaming the individuals struggling with this condition.
And certainly, while private enterprise may in some cases provide solutions, given the number of money printing weight-loss scams out there, much of this can certainly be construed as simple exploitation of a vulnerable and desperate population.
If this is what private enterprise is about – count me out.
Continuing in my discussion of the weight and health outcomes of the APPLES study, reported by Padwal and colleagues in Medical Care, we now turn our attention to the 150 participants who underwent bariatric surgery in a publicly funded bariatric program.
As noted in yesterday’s post, all surgical patients underwent intensive medical assessment and behavioural interventions prior to undergoing surgery. Thus, the outcomes reported in this group of participants is on top of any weight loss or benefits that patients may have experienced as a result of this intervention prior to surgery. It is thus, not surprising that at the time of enrolment to the APPLES study, surgical participants were approximately 4 Kg lighter than the “medical” participants (this being the average weight loss seen in the “medically” managed group).
Of the 150 surgical participants, 129 (86%) completed their 24 month visit. Data for the “drop-outs” was analysed as “last-observation-carried-forward”.
Overall weight loss at 24 months for the surgical group was 22 Kg (16.3%) with 75% achieving more than 5% weight loss, and 63% achieving more than 10% weight loss.
There were distinct differences in weight-loss outcomes between the different surgical procedures (all of which were performed in approximately equal proportions).
While the average weight-loss at 24 months for patients undergoing adjustable gastric banding was a paltry 7 Kg (5.8%), sleeve gastrectomy patients lost 21 Kg (16%), whereas bypass patients lost 37 Kg (26%) of their initial body weight.
All of these weight-losses were associated with marked improvements in cardiovascular risk factors.
There are several important learnings from this data.
1) Surgical treatments were markedly more effective than behavioural intervention (no surprise here).
2) There are significant differences in the amount of weight lost with the different surgical procedures, with bypass patients losing almost five times more weight that those undergoing gastric banding (rather unexpected).
3) Even with the greater weight loss achieved through surgical treatment, the average weight loss is still well under 30% of initial weight – again speaking to the refractoriness of severe obesity even with surgery.
Thus, despite its greater efficacy, even bariatric surgery will still leave many patients obese (based on BMI).
For clinicians (and patients) this means that many patients undergoing bariatric surgery, despite significant weight loss and considerable improvements in health and quality of life, may still be disappointed to not achieve their “ideal” or “dream” weight.
In the next post, I will summarize the overall learnings from this study and what they mean for the current status of bariatric care.
Padwal RS, Rueda-Clausen CF, Sharma AM, Agborsangaya CB, Klarenbach S, Birch DW, Karmali S, McCargar L, & Majumdar SR (2013). Weight Loss and Outcomes in Wait-listed, Medically Managed, and Surgically Treated Patients Enrolled in a Population-based Bariatric Program: Prospective Cohort Study. Medical care PMID: 24374423