Associate Professor Marion Haas, Centre for Health Economics Research and Evaluation (CHERE), UTS

Slide 2: In this presentation I will be examining the issue of obesity. Much has been written in both popular and academic literature about obesity. I cannot hope to cover all the issues in detail; what I will attempt to do is share with you some questions that I, as a researcher and evaluator, have about this topic – and some of the answers (or lack of them) that I have discovered. I will also be trying to avoid the hyperbole that has accompanied some of the coverage of this issue both by the media and academics.

Slide 3: The questions that I have are

1) How fat are we? I will provide a very brief overview. There are two distinct perspectives on obesity – the population or pubic health perspective and the individual perspective. As I believe that these perspectives inform the public debate now being waged in both the media and amongst academics, and that they will also inform policy responses, I think it is important to discuss both briefly, asking:

2) Are population-level and individual-level perspectives on obesity compatible?

3) Finally, the question that, as an evaluator, I am most interested in: What evidence is there about how obesity might be prevented or "treated"?

One caveat: I am largely considering the issue of Obesity. I have deliberately tried to separate the issues of Obesity and Overweight. They are often reported together but there are some important differences, particularly in terms of their effects on health and ability to function.

Slide 4: Obesity is the over accumulation of fat that exceeds the body's skeletal and physical standards. Conventionally, it is measured by comparing height and weight as illustrated on this slide. To read the slide, compare your weight along the horizontal axis with your height on the vertical axis. A BMI of more than 30 is the point at which excess weight is considered a health risk and the risk rises as BMI rises.

Slide 5: What do different levels of BMI look like? Here is a fairly scary picture; it also illustrates that a BMI of more than 40 is labelled "morbidly obese". It is important to note that BMI is not a very accurate measure of the levels of fat in the body. Individuals, may be large and not obese (eg rugby footballers) so BMI may not be the best indicator of the health effects of OW and Obesity- but this is not an issue I can address here.

Slide 6: 1) How fat are we? From a population perspective, in Australia, obesity seems to be a growing problem. Analyses of the 1995, 2001 and 2005 NHS undertaken by Glenn Jones and colleagues at CHERE show that obesity grew among women aged 25-64 from 10% to 17% and in men from 11% to 16%. Estimates of the proportion of the population that is obese vary depending on whether the information is self-reported or measured. These numbers are from measured height and weight, not self-reported height and weight. Some surveys of measured BMI (as reported in 2 surveys such as the NHF Risk Factor prevalence surveys, the National Nutrition survey and the AusDiab survey show that a higher proportion than this are obese - in men it may be as high as 20%..

Slide 7: Man are more obese than women, and although I have not illustrated it here, obesity appears to be growing faster among men also.

Slide 8: As can be seen from this chart, whether obesity is self-reported or measured, the level of obesity in Australia is not much different to that in NZ and Canada, lower than in the US and the UK but much higher than in Italy. Italy is similar to most continental European countries in terms of population levels of OW and Obesity. There is some evidence that the Dutch eat as much as the English, but are not nearly as fat. Why are English-speaking countries different?

Slide 9: However, the most striking differences in obesity can be found between relatively disadvantaged groups in the community. Looking at the darker bars at the bottom of the columns, we can see that in 1995 and 2001, women and men who lived in areas of most socioeconomic disadvantage were more likely to be obese than their least disadvantaged counterparts.

Slide 10 Within this general category of relative disadvantage, however, there are some important differences: lower levels of education (post-school quals vs no PS quals) are associated with higher levels of obesity. In 1995 being unemployed was associated with significantly higher levels of obesity; in 2001, the differences between the employed and unemployed was not significantly different. People on lower incomes are more likely to be obese, but we have no comparative data before 2001, so we do not know if this is a continuing trend. Aboriginal people are much more likely to be obese than non-Aboriginal people and this disparity has increased substantially over time. It is important therefore to note that generalities can be deceptive.

Slide 11: Using survey data to provide a snapshot of the population-level rates of obesity provides one view of the problem, but longitudinal studies which follow the same individuals over time also provide relevant insights. In the LSAW, more than 7000 women regularly answer questions about many aspects of their health. Results from this survey show that between 1996 and 1998, half the mid-aged women in the study (ie women in their 40s and 50s) maintained their weight within 2.25 kg, with one third gaining more than this over a 2 year period.

Weight gain and weight loss were both associated with poorer mental well-being while weight gain was also associated with a loss of physical well-being. This sounds bad but the difference between the mean scores of those with the best and worst well- being was 2; this is unlikely to be clinically significant and almost certainly would not be noticeable in terms of a woman's ability to function, physically or mentally. As the study continues, it will be interesting to observe future trends, particularly to assess whose weight changes. There are no such data for men.

Slide 12: So there are two potentially confusing views here – depending on whether the population or individual-level perspective is chosen. 2) To what extent are these perspectives compatible in terms of a policy response? Behind all the population-level information about obesity are individual-level decisions about what to consume, how much to exercise etc. Individuals are influenced in their behaviour at least partly by 3 the resources available to them – personal resources such as their capacity to understand and act on information about eating, drinking and exercising and environmental resources in terms of their ability to access suitable food and exercise opportunities. Ultimately, the decisions people make reflect a personal perception about what will maximise their well-being, within their particular circumstance. Their decisions may be different from what experts believe to be "right" or "healthy".

Slide 13: We know that being informed about what is "right" is different from acting on that knowledge. In work using the 1995 NHS and the linked National Nutrition Survey Glenn Jones and Elizabeth Savage and colleagues from CHERE showed that under-reporting about the consumption of food was systematically related to BMI. In the box on the left, (and looking at the horizontal axis from a BMI of about 25 onwards) we can see that self-reported consumption fell as BMI rose. This applied to all food, including snack food and fast food. In the box on the right we can see the opposite effect which only occurred for one category of food - diet soft drinks.

Slide 14: for OW people, some over-consumption may be due to a mis-perception about their weight. Using the 1995, 2001 and 2005 NHS Elizabeth Savage and colleagues at CHERE have shown that over time, more OW individuals are under- perceiving their body mass compared to people with normal weight, for both men and women. Individuals who go from normal to overweight increase their chances of under-perceiving their body mass. Smoking (or taking up smoking) increases an individual's chances of under-perceiving but changes in patterns of drinking or exercise doesn't have much of an effect on an individual's perception of body mass. In changing their perceptions of what a healthy weight is, OW individuals may be convincing themselves their weight is not such a big deal.

Slide 15: Is it a big deal? Population health experts advocating action on obesity have taken to using the word epidemic. Being obese has been compared to smoking, and has been claimed to cause (among other things) global warming (due to increased use of fuel by the airline industry as they carry increased numbers of obese people), car accidents and suicide! As well as being emotive and not correct – obesity is not a communicable disease - I don't think this particular label is helpful. It might be seen to imply that there must be an immediate, emergency response on the part of expert "saviours" to protect the innocent and save those already "infected". I believe that a more nuanced approach is necessary for a number of reasons:

Slide 16: First, how likely is it that an approach that emphasises panic about eating and exercise will affect those at risk of developing eating disorders such as bulimia and anorexia? Underweight is a serious health issue and should not be discounted. Second, the discussion about the effects of obesity usually includes information about increased risks of heart disease, diabetes, arthritis etc. But these are population-level risks; they do not necessarily apply to the individual. At an individual level, most risk factors have poor discriminatory power, or poor predictive value. This means that for an individual, taking difficult and expensive preventive action to ward off a small personal risk does not make sense. From the perspective of the individual, the odds are pretty heavily in favour of survival in relatively good health, without any behavioural change. Moreover, the consequences of unhealthy behaviour are usually a long way off. At the risk of labouring the point, here is the trade-off: immediate 4 certain pleasure vs future uncertain chronic disease. In our society at least, appearance not future health seems more likely to motivate weight loss.

While there is no doubt that there may be additional cases of some chronic conditions as a result of obesity, the effects on survival shown in the next slide demonstrate why individuals may be right to regard their individual health risk as low

Slide 17: Calculations by US researchers (Fontaine et al, 2003) show that at age 30, a woman is likely to lose 3 years of life whether she has a BMI of 18 (remember that 18.5 is the lower level of normal BMI) or a BMI of 38 (ie be severely obese). The same applies to women aged 40, 50 or 60

Slide 18 The argument that the health services will be overwhelmed by the costs associated with treating obesity and its side effects is somewhat dramatic, I believe. Health economists are aware that cost of illness calculations are highly dependent on the method used to calculate them and can vary by many millions of dollars depending on what assumptions are made about uncertain, future events – however, there are always large numbers. In addition, most such calculations are not, strictly speaking, correct. They often do not take account of any benefits of interventions, and, in this case, any health benefits of obesity. For example, it has been claimed that rates of osteoporosis will be lower amongst a fatter population. In a very recent study of LOS and obesity undertaken by the CHE at Monash University, researchers found that obese patients stayed longer is some specialities, average times in many and shorter times in others. This means that it cannot simply be assumed that it is more costly to treat obese people, on average (Hauck and Hollingsworth, 2008). Finally, the health services have been able to adjust to changed facets of illness and technology in the past and there is no reason to suspect that they won't be able to in the future. Obese individuals have always been among those admitted to hospital – until recently, they seemed to manage in regular beds rather than the special very expensive beds that are now being manufactured and sold to hospitals.

Slide 19: There are values at play here which should not be ignored- witness the focus on the YLL lost due to obesity rather than underweight. In the popular media, (eg in shows such as the Biggest Loser), moral overtones can be observed. And the public health discourse about an obesity epidemic may be a misplaced attempt to shift the blame from the individual. None of this is helpful in terms of a policy response. How can obesity be prevented or "treated"? Even a cursory examination of the literature is not very positive. None of the commonly proposed solutions have much, if any good evidence to back them up.

Slide 20: (Nagging). There are many ways in which obesity cannot be compared to tobacco, and the type of education campaign that has been run for both topics is a good example. Anti-smoking campaigns are run as seriously negative advertisements portraying the disease consequences of tobacco. Education campaigns targeting obesity focus on informing consumers about healthy food choices and encourage more PA. Who is most likely to be able to take advantage of such advice? Healthy food choices are less accessible to some groups in the community and may be more expensive; what is true is that food with the highest fat content is the cheapest! People on higher incomes are more likely to have both the time and the money to undertake PA as a leisure pursuit. But, can even the richest and best educated do it? Only a third of the women in the LSAW were able to comply with more than half the current 5 guidelines and only between 43% and 60% reported being able to meet the recommendations regarding F&V. This indicates that the current guidelines are unachievable for many (Ball et al 2003).

Slide 21 Regulation of advertising. Food is not tobacco. It is not one behaviour like smoking, but represents a lifelong series of personal choices, mediated by genetic, family, social and cultural mores. Unlike tobacco, it is not an unnecessary product, but is necessary to sustain life. Unlike tobacco, only the over-consumption of food is (somewhat) unhealthy and even then, it affects only the individual who consumes it (in contrast to passive smoking). Calling for bans on advertising infers that consumers are powerless to resist advertising, that they are somehow at the mercy of the fast food industry or of their children. There is no evidence that changes to advertising would have a significant impact on population levels of obesity.

Slide 22 Preventing obesity by targeting children. There is a fair argument that children cannot make the same rational decisions as adults regarding consumption and exercise and hence some collective action is justified. The trouble is, we are relatively ignorant about what might work. In some work we are doing with NSW Health and one AHS around what might be an appropriate level of investment in programs aimed at preventing obesity in children, it has become clear that although interventions reported in the literature and the programs implemented at the AHS target similar behaviours, the research interventions tend to target one behaviour at a time (eg consumption of sweetened drinks or sedentary behaviour), in contrast to the approach taken by the AHS program which is to target multiple behaviours in a coordinated strategy within a particular setting. As a result of this approach, the reach and intensity of AHS-based activities bear little or no relation to that reported by research- based interventions. Although this is an important issue and reflects a relative lack of investment in health promoting activities compared with that devoted to acute health care, it may be only a minor issue compared with the problem that we have no evidence that changes in behaviours will result in decreased obesity amongst children or if any changes will persist into adolescence or adulthood.

Slide 23 It is difficult to design rigorous trials of interventions in the face of political pressure to do something, problems in measuring and thus "targeting" obese children and the costs of mounting large scale population-based multi-factorial interventions. We at CHERE are part of a team evaluating the costs and outcomes of a large-scale program aimed at preventing obesity in children which is being implemented in one AHS. Whilst we may be able to compare what happens in this AHS with the rest of NSW, it is becoming increasingly clear that it will be very difficult to separate out the program's effects from that of more general messages, including the increasing media coverage of this issue. Reinforcing this view, a recent review of the effectiveness of campaigns to promote physical activity in children and adolescents concluded that a lack of high quality evaluations hampers conclusions about effectiveness (van Sluijs et al 2007).

Slide 24 The other popular suggestion from a population perspective is taxing fat (or perhaps sugar or maybe both) in food. While taxes have been shown to contribute to changing behaviour in other areas (eg smoking), there are some difficult issues with respect to feasibility, including what would be taxed, how would it be calculated to account for different types of food, means of preparation and nutritional value and 6 how much would it have to be to have an effect (20%?). Careful thought would need to be given to how to compensate lower income people.

Slide 25 Turning to "treating" obesity. These interventions fall into two categories: things that can be "done" to individuals and things they have to do themselves. Drugs and surgery obviously belong to the first category. Trials on drugs currently available have been associated with average weight losses of between 2.5 and 3.5kg after 2 years as well as beneficial changes to risk factors such as blood pressure and cholesterol (with the exception of Sibutramine which is associated with an increase in Diastolic BP). So most drugs are pretty safe but do not have a major impact on weight and there is no information available about long-term effects. At the present time, surgery is the most effective long-term treatment for the obese. Evaluations indicate that 30% will lose more than 30% of their body weight. Unfortunately, 30% will also have nasty complications including vomiting, stomal narrowing, pulmonary emboli and major post-operative complications. In the absence of long term data about the effects of either drugs or surgery, it seems unwise to recommend their introduction on a large scale at the present.

Slide 26: Things we have to do ourselves: I am talking inclusively now because results from the LSAW indicate that a majority (74%) of women in the mid-age group (47-52 years) are actively trying to control their weight using practices consistent with public health measures (Williams et al, 2007). Two-thirds of the women used a combination of methods eg 32% cut down of food intake, decreased fats and sugars and exercised while a further 16% cut down on food, fats and sugars but did not exercise. The cohort as a whole (ie those who were trying to lose weight and those who were not) gained an average of just under 5 kg over a 2 year period. Although women who used a combination of strategies to lose weight did not gain as much as the overall group, the only group that actually lost weight used a combination of cutting meal sizes, fats, sugars and snacks and used a commercial weight loss program Those who lost weight were not only the obese (ie the most desperate), but they did have the capacity to pay. Was it the payment or the individual attention or (in some programs) the effect of social support that helped most?

Slide 27: Losing weight is very hard. In work we have done in Whyalla, SA, (as part of the ATN Centre for Metabolic Fitness), we tracked individuals' attitudes and preferences as they attended a lifestyle intervention program. At baseline participants indicated a preference for an individually designed exercise program, reasonably structured diet programs and high levels of support. At 4 months the focus shifted to a clear preference for exercising alone and an aversion for organised group exercise. Support was no longer significant and a strong preference emerged for a flexible dietary regime. Participants moved away from wanting structure and supervision and towards more flexibility. At 12 months cost became a major factor and there was evidence of renewed interest in having higher support, flexible diets, individual exercise and a weekly meal program. Overall, individuals who lost weight were more likely to take an active interest in their program and to assess their own needs rather than relying exclusively on others' directions.

In a second project under the auspices of the Centre for Metabolic Fitness, we have been involved in evaluating a program called Choose Health in which cognitive behavioural therapy is used as an intervention for obese adolescents. This is a 7 resource-intensive 12 week program; the initial results showed that adolescents receiving the intervention lost significantly more weight than those not receiving it, but remained obese. A major issue is that there is no long term follow-up of the individuals and no evidence available about the likely impact on either costs or outcomes in the future which could be used to justify such follow-up.

Slide 28: The obesity epidemic discourse gives the impression that if only we (collectively) had acted when we saw how bad things were becoming, things wouldn't be this bad and we could avoid worse in the future. But what would we have done? Although it is interesting to observe, there seems no possibility to me that the population would accept a shortage of food and fuel (as happened in Cuba in the 1980s when the SU collapsed), and which was associated with dramatic falls in the rates of CHD, diabetes etc. Any such development is likely to differentially affect the poor and disadvantaged, who already bear the highest burden of obesity. Nor is there likely to be a wholesale conversion to a lifestyle such as that practised by the Old Order Mennonite where non-use of motorised transport and information technology such as TVs, computers and an agricultural way of life is associated with healthy, non-obese children and longevity (Tremblay et al 2005). Thus, the uncertainty about the efficacy of available and acceptable solutions is a real issue.

Slide 29: In the lead up to the election and in the budget, the Federal government has committed nearly $22m to programs targeting obesity and healthy nutrition. I think it is highly questionable that more should be spent on public health campaigns for which there is no evidence of effectiveness, either in terms of encouraging wide- spread changes in behaviour or that such behaviour change will be sustained. The policy debate needs to be conducted carefully, facing the issue that there are risks associated with the take-up of messages by non-target groups and non-take-up of general messages by poorer and disadvantaged groups. How do we design policies that motivate individuals to act when the rational option is inaction?

Slide 30: If we are to increase our knowledge of the causes of obesity and gain greater understanding of what might work to either prevent or intervene with obese individuals, we need more and better research. One way of doing this is to ask some different questions. For example, why are some people not obese? Again using the LSWH, Ball and colleagues showed that weight maintainers (ie women who were within 5% of their original weight 4 years later) were more likely to be in a healthy weight range to start with and to report they spent less time sitting and consumed less take-away food than those who gained weight. The ATN CMF is establishing a Weight Control Registry, a prospective cohort study to identify what works, what doesn't, what works best for whom in long-term weight management. This information will be useful in improving existing weight management programs.

While it is vital that evaluations of interventions are methodologically rigorous, at this stage of our knowledge, it is more important that resources are devoted to research about what potential interventions might look like. To do this, we need panel or longitudinal data to track individuals' progress over time (eg in terms of weight, weight loss, health status etc), linked to health services databases (such as MBS, PBS, hospital data, cancer registry data), so that we can fully understand the impact any preventive and/or intervention efforts have had on the use of expensive health services. Such linkage is possible; compared with funding the infrastructure required 8 for basic research, it is cheap. If policy makers are serious about obesity, this should be one of their first priorities!

Slide 31: Of course, we cannot wait on the sidelines until all the results of this fabulous research are available. Let's start by thinking about interventions that conform to that old adage "first, do no harm". In the face of polluted cities and increasing concerns about the environment, as well as obesity, modifying the environment to enhance "greenness" (bicycle paths, better public transport, more parks and bushy spaces etc) may also encourage greater levels of exercise. Ensuring that all parts of the country and all individuals have the means to access fresh healthy food is good public policy and may have a positive impact on obesity. There are remote communities and disadvantaged areas in our cities or on the fringes of towns where fresh food is either not available and/or not affordable. Here is where private enterprise can play a role – everyone needs the fresh food people. Even mandatory canteen strategies are unlikely to be harmful given that we already accept a number of restrictions at school now in the name of health (ie no peanuts, wearing hats etc) and children will have other choices apart from canteen food. Until there is evidence to the contrary, I would be cautious about increasing the load on a crowded school curriculum. Governments do have an obligation to inform citizens about what to do to protect their health; the messages must be simple, consistent and promote realistic consumption behaviours. Taxes will change prices which we know will change behaviour, but must be carefully thought through in terms of their likely effects on behaviour amongst all groups in society. Finally, we must also accept that there will be a limit to the effectiveness of both prevention and intervention for obesity. We must take care not to invest unwisely when no collective action can with certainty control what individuals eat and drink and how much they exercise.