APPENDIX 32
Memorandum by the Insitute of Human Nutrition,
University of Southampton (COB 56)
INTRODUCTION
This response has been formulated by senior
staff members of the Institute of Human Nutrition at the University
of Southampton—Dr Stephen A Wootton, Prof Marinos Elia and
Prof Alan A Jackson. As an academic group within a major teaching
hospital, we have a particular commitment to improving the health,
wealth and well-being of society in terms of both public health
nutrition and clinical nutrition delivered by health professionals
in the UK and overseas. Members of the Institute also hold senior
responsibilities within national governmental and professional
committees and organizations relating to the delivery of health
care in the UK.
We welcome that there is to be a government-led
initiative to address the health implications of "obesity".
We applaud any serious consideration which might lead to a reduction
in the burden of ill-health associated with excessive gain in
weight. It is important to appreciate that the inexorable increase
in the body weight of the population and its attendant health
risks have occurred over a period when we have been very well
aware of simple models which relate patterns of food intake and
levels of activity with energy balance. This global, cross-cultural
change belies our current understanding of the relevant biology.
The examples of approaches which appear to have been efficacious
in dealing with the problem have been based upon a much broader
base of understanding of social and behavioural considerations.
The potential of the examples has not been sufficiently explored
in the UK, nor the resource implications were they to be adopted
as a fundamental aspect of the promotion of health and the treatment
of ill-health for the population.
The comments below are directed specifically
at recommendations for national and local strategy.
EVIDENCE FOR
CONSIDERATION
1. The scale of the problem is considerable
and increasing. The problem is complex, resulting from a poorly
defined interaction of biological, psychological and sociological
factors. Identification of effective interventions presupposes
an understanding of these interactions and how they lead to excess
weight gain and constrain weight loss, particularly in those at
increased risk. Policy must be directed towards those in society
most at risk, or where the burden of disease is greatest. The
challenge is that interventions are most likely to be successful
when they address the problems experienced by those most likely
to benefit from such initiatives: young people, and those who
are most deprived in the society: groups that are notoriously
difficult to access and influence. We propose that the Committee
consider how to direct policy towards those most likely to benefit
from an initiative to improve morbidity and mortality associated
with excess weight gain.
2. There is a pressing need to differentiate
between those strategies which are designed to prevent excessive
weight gain in children and adults, or enable adults to maintain
a body weight that is associated with the lowest risk of ill-health
(community setting), and those strategies which are designed to
reduce weight in the treatment or management of those with ill-health
as a consequence of, or associated with, excessive weight gain
(therapeutic care at primary, secondary or tertiary levels). Each
will require effective use of health care resources, but the nature
of the resource is likely to be different for the two different
aspects of the problem. It is likely that for community-based
preventive interventions there will be the need to develop novel
approaches to the delivery of care. We propose that the Committee
consider novel approaches to the delivery of care in community-based
preventive interventions.
3. There has been a substantial increase
in the proportion of children with excess weight in relation to
their height. This is a matter of considerable concern, but some
caution needs to be exercised in assuming that the nature of the
problem in children is the same as, or similar to, that seen in
adults. The level at which weight gain in children is associated
with an increased burden of ill-health both in the short-term
and the long-term needs to be clarified. There is the need to
determine whether the approach to prevention, or therapeutic management
in the overweight child, should be the same of different to that
adopted for adults. The information is not yet available to be
clear on this important point. We propose that the Committee call
for further research into the level at which weight gain in children
is associated with an increased burden of ill-health both in the
short-term and the long-term.
4. There are many different approaches to
weight management in those with increased morbidity and mortality
associated with excess weight gain. A substantial industry has
developed based upon the hopes and high expectations of clients.
Some of these interventions may have limited success in the short
term, but most fail in the longer term. There are some important
exceptions, and more recently there have been a series of randomised
controlled trials using accepted scientific methodology, and approaches
which use behavioural therapy operating within constructs which
recognize the interaction amongst biological, psychological and
sociological factors. Some of these have been shown to be successful
in achieving a reduction in body weight, together with improvements
in risk factors associated with morbidity and mortality [1-5].
Most of these studies have taken place in the context of a research
setting, and therefore are measures of efficacy. We know of no
studies where the context of the study has allowed a determination
of the effectiveness of the intervention. This work has been carried
out overseas and it is unclear whether similar approaches would
have equivalent efficacy, and effectiveness when carried out within
the health care setting in the UK. We propose that the Committee
call for further research into the effectiveness of behavioural
therapy-based interventions when delivered within the health care
setting in the UK.
5. The management of the obesity epidemic
at a national level is more likely to be successful if a co-ordinated
policy is established, in which food manufactures, government
officials, city planners, educationists and health professionals
all work together. The tendency for the various sectors to take
credit for successes, but cast blame for any limitations, does
little to help matters, and imposes barriers to effective management
of the problem. Differences in perceptions and attitudes which
act as a barrier to different sectors operating effectively together
need to be identified, and where possible reduced or eliminated.
We propose that the Committee call for further research into identifying
and tackling the barriers to the delivery of a co-ordinated policy
of care.
6. The health care setting in the UK is
well structured to deal with established disease, but poorly developed
in terms of effectively supporting life-style changes that have
been shown to work. Thus there are a number of factors which will
operate to constrain the likely success of any attempts to introduce
weight management initiatives within the traditional health care
system. We believe there are a number of specific factors which
militate against success, but there are three principle issues,
which would need to be addressed as a matter of urgency, if there
were to be any serious attempt to deal with the problem of excess
weight in the population.
(a)
Firstly, although some attempt has been made to establish
an infrastructure for dealing with obesity, in general the management
of the process is not well co-ordinated. This means that there
is no accepted structure or mechanism in place through which effective
interventions might be delivered. There is a notable absence of
well-structured and validated care pathways. Furthermore, there
is no formal budgetary responsibility at any level of care—community,
primary, secondary or tertiary—for the identification of
overweight, and the support and management of those identified
as being at special risk. Without a proper infrastructure within
which care can be delivered with an integration of purpose, it
is impossible to use common internally consistent benchmarks to
monitor progress. We propose that the Committee consider how it
would be possible to define an infrastructure, with validated
care pathways and budgetary responsibility, for dealing with the
prevention and treatment of excess weight gain at all levels of
care.
(b)
Secondly, there is an absence of an identified lead
professional with the necessary knowledge and skills, who accepts
formal responsibility for weight management and obesity care.
Without suitably trained lead individuals it will not be possible
to examine the effectiveness of existing or new approaches to
care, nor plan and co-ordinate the delivery of care. While there
are a number of different categories of health professional who
should play important roles in delivering safe and effective care,
there is no single group of health professionals who are currently
in a position to provide the necessary lead. This is because there
is no single group of health professionals that has received appropriate
training, or possess the necessary knowledge and skills to oversee
the prevention of weight gain, or the management of excessive
weight, in children and adults. For example, at present overweight
patients are referred to a state registered dietitian (SRD), many
of whom are based in the hospital setting, although some are community
based. Although, dietitians are trained in the dietary aspects
of weight management, as a workforce they are not adequately equipped
to deliver care that is centred on the more difficult aspects
of changing behaviour, or establishing sustained changes in lifestyle,
which should particularly include changes in physical activity.
Even with the most optimistic predictions, this particular group
of practitioners are unlikely to be able to cope with the problem
as it exists for the foreseeable future. They already have a rapidly
expanding portfolio of responsibilities for care, which greatly
exceeds their ability to cope without a substantial increase in
the numbers of staff. An alternate approach would be to consider
the development of a new cadre of health workers who are trained
in public health nutrition and issues related to weight management.
A specific aspect of their remit would be to take a lead in working
with other health professionals (for example, SRDs accredited
in exercise and sport; clinical psychologists; nurse practitioners)
primarily in the community, but also in hospital settings. We
propose that the Committee consider the development of a new cadre
of health workers trained in public health nutrition and issues
related to weight management who can take a lead role in the implementation
of a co-ordinated health care strategy for obesity.
(c)
Thirdly, there is the need to have greater clarity
in identifying the most important outcomes of any interventions.
There is the need to extend the primary outcomes of any initiatives
beyond a simple consideration of weight loss to one that encompasses
a reduction in mortality and morbidity. The important question
is whether benefits in outcomes can be achieved, without necessarily
having to achieve and maintain a substantial degree of weight
loss. Weight is useful and has been taken as a marker for an increased
risk of morbidity and mortality, but there is the need to consider
the factors which operate to reduce or effect morbidity and mortality
directly. Our present conceptual approach to obesity is centred
on excess weight, most simply marked by BMI. We use this measure
as a way of identifying those most at risk of ill-health and the
need for intervention. This approach presumes that it is the presence
of excess weight or fatness itself that confers the increase in
risk. Therefore, the logic is that a marked reduction in weight
is required to confer any benefit. However, there is emerging
evidence that challenges this view. Modest weight loss (5-10%)
is associated with marked improvements in the constellation of
risk factors that are known to be associated with cardiovascular
disease (CVD) and insulin resistance (IR) (ie circulating lipids,
insulin sensitivity, haemostatic factors). More importantly, excess
weight or fatness (as BMI or waist circumference) of itself is
an inadequate measure of CVD risk. For example, obese individuals
with a high level of cardiovascular fitness have been shown to
have a lower CVD risk than lean or normal weight individuals who
are unfit [6]. In the same way, differences in metabolic behaviour
marked by elevated levels of triglyceride in the blood appear
to be a more discriminatory marker of the metabolic syndrome than
waist circumference [7]. Taken together, evidence of this kind
requires that we re-examine the separate and combined effects
of body mass on the one hand (excess weight or fatness) and individual
metabolic phenotype on the other (differences in macronutrient
partitioning and hormonal control) on ill-health. We propose that
the Committee call for further research to better understand what
determines the metabolic competence or phenotype of an individual
and how this interacts with lifestyle (in particular the types
and amounts of food consumed and physical activity) to determine
both the composition of the body and the mechanisms that link
weight or change in weight to the development of CVD and IR.
REFERENCES:1. Riebe
D, Greene GW, Ruggiero L, Stillwell KM, Blissmer B, Nigg CR, Caldwell
M. Evaluation of a healthy-lifestyle approach to weight management.
Prev Med 2003; 36(1):45-54.
2. Andersen RE, Wadden TA, Bartlett SJ, Zemel
B, Verde TJ, Franckowiak SC. Effects of lifestyle activity vs
structured aerobic exercise in obese women: a randomized trial.
JAMA 1999: 27;281(4):335-40.
3. Andersen RE, Franckowiak SC, Bartlett SJ,
Fontaine KR. Physiologic changes after diet combined with structured
aerobic exercise or lifestyle activity. Metabolism 2002; 51(12):1528-33.
4. McManus K, Antinoro L, Sacks F. A randomized
controlled trial of a moderate-fat, low-energy diet compared with
a low fat, low-energy diet for weight loss in overweight adults.
Int J Obes Relat Metab Disord 2001; 25(10):1503-11.
5. Saris WH, Astrup A, Prentice AM, Zunft HJ,
Formiguera X, Verboeket-van de Venne WP, Raben A, Poppitt SD,
Seppelt B, Johnston S, Vasilaras TH, Keogh GF. Randomized controlled
trial of changes in dietary carbohydrate/fat ratio and simple
vs complex carbohydrates on body weight and blood lipids: the
CARMEN study. The Carbohydrate Ratio Management in European National
diets. Int J Obes Relat Metab Disord 2000; 24(10):1310-8.
6. Lee CD, Blair SN, Jackson AS. Cardiorespiratory
fitness, body composition, and all-cause and cardiovascular disease
mortality in men. Am J Clin Nutr 1999: 69, 373-379.
7. Lemieux I, Pascot A, Couillard C, Lamarche
B, Tchernof A, Almeras N, Bergeron J, Gaudet D, Tremblay G, Prud'homme
D, Nadeau A, Despres JP. Hypertriglyceridemic waist: A marker
of the atherogenic metabolic triad (hyperinsulinemia; hyperapolipoprotein
B; small, dense LDL) in men? Circulation 2000;102(2):179-84.
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