What is Obesity?

Don't worry - I am not going to take off on a discussion about whether obesity is a disease or "simply" a risk factor. I am also not going to discuss again obesity definitions - anthropometric or otherwise.

Today's post is simply about an analogy that may help sharpen our clinical thinking around excess weight.

Think of someone who has an elevated plasma creatinine level (a marker of kidney failure) - the elevated creatine definitely tells us that there is something "wrong" with the kidneys, but that's about it. From the creatine level alone we can certainly tell that the kidneys are failing in their excretory function, but we cannot tell what is causing the kidneys to fail - is it a pre-renal, intra-renal or post-renal problem? We can probably list a 100 reasons why kidneys could fail and obviously the treatment (apart from some very general principles) will very much depend on the cause, i.e. the actual diagnosis.

In many ways, one can look at excess body fat simply as a sign or symptom of the fact that there is a something "wrong" with energy homeostasis. The excess body fat tells us nothing about what the problem is - sure, it's either excessive food intake or reduced energy expenditure - but that is like saying that the creatinine levels are elevated because the kidney is not excreting properly. I can think of a long list of reasons or factors that would contribute to excessive caloric intake or reduced energy expenditure: sociocultural factors, psychological factors, biomedical factors - figuring out what exactly is causing the energy imbalance is the real problem.

Only when we find what is causing the excessive intake will we have made a diagnosis of what is causing the problem - a few specific examples could include: poor meal planning, peer pressure, hedonic overeating, depression, obesogenic medications, binge eating disorder, defective satiety signaling, etc. The point is that till we know what is causing the overeating, we can't fix it, which means we will have little success in treating the weight problem and will be limited to a "symptomatic" approach - just eat less!

Similarly, when the problem appears to be lack of activity, again the question is what exactly is causing the problem. Obviously if the problem is lack of time our approach will hopefully be very different than if the problem is back pain or lack of motivation (a possible symptom of sleep apnea, exhaustion or depression). A "symptomatic" but useless approach would be to simply recommend 10,000 steps. No better than offering an ice-pack to someone with a fever.

Just as the term "kidney failure" only tells us that there is something "wrong" with the kidneys the term "obesity" only tells us that there is something "wrong" with energy homeostasis.

In itself, neither the term "kidney failure" nor "obesity" is a real diagnosis - they are only helpful if they prompt further investigation into what might have or is still causing the problem. Only when we find the cause will we be on our way to solving the problem.

AMS
Edmonton, Alberta

Overeating is a Symptom

Last week, I blogged about the results of a study showing an association between vital exhaustion and weight gain.

This blog posting prompted Sharon Kirkey (award-winning health journalist and diligent reader of my blog) to explore this issue further by actually talking to the researchers themselves. Her article appeared yesterday via the Canwest News Service and contains far more details than I bothered to report in my blog.

For e.g. Sharon lists the actual questions Bryant and colleagues used to explore the presence of vital exhaustion. I found them most interesting so I list them below:

- Do you often feel tired?

- Do you wake up repeatedly during the night?

- Do you have the feeling that you have not been accomplishing much lately?

- Do you believe that you have come to a 'dead end'?

- Do you lately feel more listless than before?

- Do little things irritate you more than they used to?

- Does it take more time to grasp a difficult problem than it did a year ago?

- Do you have increasing difficulty in concentrating on a single subject for long?

While to me none of these questions seem particularly specific and are likely to get a "yes" response from a lot of people (hey, even I have to say "yes" to some), I guess when you have to say "yes" to most or all of them, you are probably not hopping around like the Energizer Bunny or scrambling to follow diet plans.

Sharon quotes me as saying:

"Nobody is claiming all of obesity is exhaustion, but if people are clearly eating more than they need the question is not (just) how to get them to stop, but why, exactly, are they doing that. Maybe you're losing your job. Or you're overworked. Or it's some private issue that needs to be addressed. You don't fix obesity by giving people a copy of Canada's food guide. You have to try to understand what it is that's contributing to the weight gain."

Exactly! Obesity is a symptom of overeating, which in turn is a symptom of something else that's going on: it can be that you simply lack the knowledge about healthy nutrition or caloric content of foods, but it can also be a symptom of emotional (e.g. depression, vital exhaustion) or biological (e.g. MC-4 receptor defect) issue, medications (e.g. clozapine) or any number of other reasons I can think of.

Always remember: overeating (and/or sedentariness) is not a diagnosis - overeating (and/or sedentariness) is a symptom!

AMS
Edmonton, Alberta

Walk and Work

Two days ago I reminded readers that not too long ago, people were actually paid to be physically active. Today, choosing to be physically active actually costs money (not to mention time).

So the big challenge is, how do we reintroduce activity into the work place so that people can actually be physically active at work again (allowing them to lounge around the couch in front of the TV when they get home).

Well, one obvious solution is to create a workspace where someone can get a workout in while on the computer. That is exactly the idea behind the "Walk Station" a desk that comes matched with a treadmill instead of a chair.

The device, the science (and the hype) behind it are described in an article from the Edmonton Journal from which I quote:

The device allows people to work on their computers while walking on a treadmill at a slow speed of up to three kilometres per hour, enabling small amounts of movement that supporters say have the potential to reap big health benefits.

The product, made by Details, a unit of Michigan-based office furniture maker Steelcase, is selling 30 to 40 units per week, according to company president Bud Klipa.

The Walkstation was unveiled last year based on research from James Levine, a researcher at the Mayo Clinic, who contends that fitness can be improved through small, modest movements for people who are otherwise sedentary.

Levine's research indicates that people who use the Walkstation can increase energy expenditure by 100 calories per hour when walking at a 1.6 kilometres (one mile) per hour, helping weight loss.

The treadmill, which costs around $4,500 for a base model, never exceeds a speed of three kilometres per hour, which, according to the manufacturer, allows most people to use it for a few hours each day.

So here are my questions:

Where is the evidence that this device will actually promote weight loss?

What will prevent this device from going down the same path as previous workplace health initiatives - embraced by the already fit, ignored by the people who need them most?

Will it increase weight-based discrimination at the workplace - the thin people are walking, the overweight are not - no one stops to ask why - back pain? osteoarthritis? depression? plantar fasciitis? - excuses, excuses! Who cares!

Although is seems like a good way to reintroduce activity into the workplace, it is still "useless" activity, i.e. you are not actually paid to walk - or in other words, you don't really have to walk to get your job done.

While I personally would probably not mind having this device, I can see all sorts of problems - anyone out there who's experienced this or a similar device - I'd love to hear how this has influenced intra-office dynamics.

I will maintain my scepticism on this being the answer till I see some actual data.

AMS
Edmonton, Alberta

Don't Spare the Protein

To anyone trying to lose weight, avoiding the virtually obligatory reduction in lean body mass is always a challenge. Not only does "offloading" as the body gets lighter reduce the actual "weight-bearing" work resulting in loss of muscle mass, but also the fact that most dietary recommendations tend to also reduce protein intake to maintain a "balanced" diet can promote a protein catabolic state.

As skeletal muscle is a major determinant of energy expenditure, losing muscle mass eventually limits the amount of weight that can be lost at any given caloric deficit, resulting in an early plateau. Furthermore, as lost lean body mass tends to be replaced with fat during weight regain (catch-up fat), you end up with a greater fat mass than before your diet.

The importance of maintaining protein intake during diet-induced weight loss was again illustrated in a recent study by Melanie Bopp and colleagues from Wake Forest University School of Medicine, Winston-Salem, NC, published in the Journal of the American Dietetic Association.

The authors investigated the association between dietary protein intake and loss of lean mass during weight loss in postmenopausal women through a retrospective analysis of a 20-week randomized, controlled diet and exercise intervention in women aged 50 to 70 years. Weight loss was achieved by differing levels of caloric restriction and exercise. The diet-only group reduced caloric intake by 2,800 kcal/week, and the exercise groups reduced caloric intake by 2,400 kcal/week and expended approximately 400 kcal/week through aerobic exercise.

Lean mass was measured using DEXA. Average weight loss was 10.8+/-4.0 kg, with an average of 32% of total weight lost as lean mass. While protein intake averaged 0.62 g/kg body weight/day (range=0.47 to 0.8 g/kg body weight/day), participants who consumed higher amounts of dietary protein lost less lean mass. These associations remained significant after adjusting for intervention group and body size.

The authors conclude that inadequate protein intake during caloric restriction may be associated with adverse body-composition changes in postmenopausal women.

I would dare to add that the same is probably true for anyone undergoing a dietary weight loss intervention that does not maintain adequate protein intake.

AMS
Edmonton, Alberta

Mood & Food

This weekend (June 8) I was part of a lunch symposium on the Complex Depressed Patient at the 30th Annual Meeting of the Canadian College of Neuropsychopharmacology (CCNP), held in Toronto.

Other members of the panel were Claudio Soares (McMaster), Pierre Blier (Ottawa) and Valerie Taylor (McMaster).

While Soares and Blier focused their discussion on a case of peri-menopausal depression, Taylor and I discussed a patient who was non-compliant with her antidepressant medication due to weight gain.

As blogged previously, weight gain is a common complication of neuropsychiatric medications and there are few proven strategies to treat or prevent it. While there is some data to support co-prescription of metformin or sibutramine with some of the psychotropic medications, this is clearly not current medical practice.

As always, prevention of weight gain may be easier than treating obesity. Thus it may perhaps be advisable to start patients on weight-gain prevention strategies (which may include both behavioural interventions and antiobesity medications) right off the bat rather than trying to treat the excess weight gain or risk non-compliance resulting from the weight gain.

As pointed out by Taylor, based on her own (unpublished) observations and other studies, weight gain with psychotropic medications is by no means benign, resulting in all of the usual complications of weight gain.

We know that simply telling people to eat less and move more is as effective for treating obesity as simply telling people to cheer up is for depression.

Both are complex multifactorial conditions that need to be addressed by behavioural, psychological and often medical interventions - not uncommonly for life!

AMS
Edmonton, Alberta

Hat tip to Bryan Ashuk for suggesting the title for this post

Obesity: It's Not TV - It's TV Dinners

People who watch more TV tend to be heavier that people who don't. The question, however, is whether it is the lack of physical activity associated with TV watching or the snacking that often goes with it that accounts for the weight gain.

This question was recently addressed by Verity Cleland and colleagues from the Menzies Research Institute, Hobart, Tasmania, Australia, in a paper just out in the American Journal of Clinical Nutrition.

This study involved a cross-sectional analysis of data from 2001 Australian adults aged 26-36 y. Waist circumference (WC) was measured at study clinics, and TV viewing time, frequency of food and beverage consumption during TV viewing, leisure time physical activity, and demographic characteristics were self-reported.

In both men and women, watching more than 3 hrs of TV per day was associated with a roughly two-fold higher risk of abdominal obesity compared to men or women watching an hour or less per day.

Interestingly, adjusting for leisure time physical activity did not change this relationship, whereas adjusting for food and beverage consumption during TV viewing did.

The authors conclude that the impact of TV viewing on weight is more likely due to the associated snacking than due to the sedentariness of sitting in front of the TV.

So if you do watch a lot of TV, watch out for those snacks and drinks.

Remember, one of the best weight management tips has always been: do not eat in front of the TV!

AMS
Edmonton, Alberta

In Obesity Variety is Bad

Humans are omnivores and apparently our hunter-gatherer ancestors ate an extraordinary range of plant and animal foods.

The advent of culinary skills and use of spices and seasonings further enhanced the variety, taste, flavour, appearance, texture and consistency of foods.

Today, the apparently limitless choice of foods in our supermarkets, restaurants and homes is a sure sign of the importance we place on variety and variation when it comes to eating.

When trying to manage your weight, however, variety may be your downfall.

This at least is the gist of a recent study by Ramona Guerrieri and colleagues from the Department of Experimental Psychology, Maastricht University, in The Netherlands, who examined the interaction between impulsivity and a varied food environment and its influence on on food intake and overweight, published in the International Journal of Obesity.

The study is based on two observations:

1) Our current food environment offers a large variety of cheap and easily available sweet and fatty foods

and

2) Impulsive people may be reward sensitive and are generally less successful at inhibiting prepotent responses (i.e. a response that is or has been previously associated with positive reinforcement)

Using a rather complicated experimental design masquerading as a taste test, Guerrieri and colleagues studied 78 healthy primary school children (age: 8-10 years) regarding two aspects of impulsivity: reward sensitivity and deficient response inhibition.

The kids were studied in two groups: one was offered rather monotonous foods; the other was offered foods varied in colour, form, taste and texture.

As expected, reward sensitivity interacted with variety. In the "monotony group" there was no difference in food intake between the less and more reward-sensitive children (183 kcal+/-23 s.d. versus 180 kcal+/-21 s.d.).

However, in the "variety group" the more reward-sensitive children ate almost 70% more calories than the less reward-sensitive children (237 kcal+/-30 s.d. versus 141 kcal+/-19 s.d.).

While reward sensitivity in itself was not linked to overweight, deficient response inhibition (a measure of impulsivity) was.

Clearly, the kids with poor impulse control were handicapped when it came to dealing with variety.

Why is this important?

What the data suggest is that kids (and adults?) who have poor impulse control are more likely to overeat when faced with variety. Therefore, the incredible variety and choices of food that we have available to us, may indeed be a major factor in the problem of overeating.

As blogged previously, attention deficit disorders (ADD) are surprisingly common in obese children and adults - in our currently environment, this increased impulsivity may be an important factor contributing to their weight gain.

If your problem is impulse control - the less choices you give yourself the better.

AMS
Edmonton, Alberta

Did Someone Mention Weight?

Given its impact on health, body weight is something that is often discussed in encounters with health professionals.

The problem is that patients may not be listening or physicians may simply not be clear enough when mentioning the topic.

This at least is the result of a recent study by Allen Greiner and colleagues from the Department of Family Medicine, University of Kansas Medical Center, Kansas City, published in the Journal of General Internal Medicine.

Post-visit survey assessments of patients (456) and physicians (30) were assessed regarding whether or not they discussed weight, physical activity (PA), and diet immediately after office visits. Patient - Physician agreement was only 61%.

There was disagreement on one of the items (weight, PA, or diet) for 23% of office visits, and for 2 or more of the items for 16% of the visits.

Agreement was relatively greater for discussing weight than for discussing diet or physical activity. Physicians reported discussing weight issues more often than did patients.

The bottom line is that patients and physicians disagreed substantially about whether or not weight issues were discussed in a large number of primary care encounters in this study.

The authors suggest that physicians may be able to improve care for their obese patients by focusing discussions on specific details of diet and physical activity behaviors, and by clarifying that patients perceive weight-related information has been shared.

Whatever the case, don't assume that just because you mention weight your patient is hearing you (and vice versa?).

AMS
Edmonton, Alberta