Energy in = Energy out

Weight management

Why do people get fat, should we worry about it and what can be done about it?

Obesity is characterized be an excess accumulation of body fat that clearly results from chronic imbalance between energy intake and expenditure.

Hippocrates wrote “Corpulence is not only a disease itself, but the harbinger of others” recognizing that obesity is a medical disorder that also leads to many other ” morbidities”.

In a report by the National Audit Office , London (2001) The number of death per year attributable to obesity is roughly 30,000 in the UK

The obesity epidemic in the United Kingdom is out of control, and none of the measures being undertaken show signs of halting the problem, let alone reversing the trend.

The United States is about 10 years ahead in terms of its obesity problem, and it has an epidemic of type 2 diabetes with obesity levels that are rocketing.

Obesity is a global problem levels are rising all over the world. Moreover, certain ethnic groups seem to be more sensitive than others to the adverse metabolic effect of obesity.

For example, high levels of diabetes and related diseases are found in South Asian and Arab population. Although most of the medical complications and cost of obesity are found in adults, obesity levels are also rising in children in the UK and elsewhere.

“…diabetes epidemic looming”

In the United Kingdom, even if preventive measures against obesity were successful immediately (so that not one more person became obese) and people who are obese do not gain weight, there would still be an epidemic of diabetes and its complications within 10-20 years. This is because so many young people are already in the clinically “latent“ phase of obesity, before the clinical complications present. Thus treatment of obesity must be prioritized alongside prevention.

(Haslam D, Sattar N, Lean M. ABC of obesity, Obesity-time to wake up. BMJ 2006;333:640-42.).

In England the national service frameworks for diabetes and coronary heart disease highlight the importance of helping patients who are obese. Obesity needs to be managed like any other chronic disease – with empathy and non-judgmental professional attitude. Helping people to manage their weight is difficult and can be discouraging and time consuming for health professional.

” …weight loss then weight maintenance”

High relapse rates, apparent lack of effectiveness, and lack of training and resources are major obstacles. General strategies for helping a patient with a weight problem include agreeing an individual, realistic, weight loss goal, such as 5-10% over three to six months. Achieving this goal can help motivate success. Aim for weight loss initially, followed by a distinct strategy for weight maintenance. Provide ongoing support and positive feedback.

The emphasis for obesity treatment use to be on weight loss. But, as identified in the 1996 Scottish Intercollegiate Guidelines Network guideline, weight loss is only one element in weight management. Management encompasses:

•    Weight loss (short term, three to six months)
•    Weight maintenance (long term, more than six months)
•    Priority reduction of risk factors.

“…frequent contact and support”

Group counseling does not seem less effective than individual counseling for long term weight change. Weight loss clubs may be helpful, but evidence is limited. For some people, however, initial individual counseling may be needed, and groups may not be beneficial-for example, for men needing support but whose local group comprises mainly of women. If possible, immediate family or key friends should be involved .

The key is prevention. Obesity is a disorder of energy balance (“energy in “ equals “energy out”). Weight is steady when energy is balanced. “positive energy balance” is when the amount of energy consumed as food and drink exceeds the energy used. UK adults on average consume 20 kcal a day more than they expand, leading to an average weight gain of 1 kg a year. Some people who become obese eat 100 kcal a day more than they expend so gain up to 5 kg a year. Any intervention that changes positive energy balance will ultimately be effective in preventing calorie accumulation, thus accumulation of body fat.

The components amenable to intervention are physical activity and overall energy consumption. The absolute level (in kcal/day), at which energy balance occurs is mainly determined by body weight, which affects both the basal metabolic rate and the energy cost of activity. It can be changed by substantial changes in physical activity but also, to a similar degree, by small changes in weight. So some thin people may be active and eat a lot to achieve energy balance, but overweight people have to eat more than most thin people to avoid weight loss.

“… effective interventions”

This purely mechanistic approach cannot be used for health promotion without a fuller understanding of several elements: the balance between individual and genetic predisposition to weight gain; the psychological, social, cultural and economic and political components of our “obesogenic” environment; and the nature of the “disease vectors” (high energy foods and energy saving devices). Changes in diet and physical activity are necessary for weight loss but do not guarantee it. To avoid compensation (between changes in physical activity and changes in appetite), effective interventions must tackle both diet and physical activity, and in an integrated way.

A successful intervention for obesity prevention must influence energy balance but must also be sustainable. Changes in diet and physical activity need to be incorporated into new behavior patterns, as a need for constant reminders or rewards will result in non-sustainability.

A permanent change in the environment is the best way to ensure permanent changes. Actions should focus on:

• enabling people to manage energy balance better on the current environment
• modifying the vectors of obesity
• changing the current sociopolitical environment, which currently rewards the manufactures of products and processes that contribute to obesity.

Effective programmes for obesity prevention probably encourage both healthy eating and physical activity (rather than rely on separate strategies for eating and activity)

References and Further reading

Haslam D, Sattar N, Lean M. ABC of obesity, Obesity-time to wake up. BMJ 2006;333:640-42.

Avenell A, Sattar N andLean M. ABC of obesity, Management:Part I Behavior change, diet, and activity 2006; 333:740-42

Lean M, Lara J and Hill J. ABC of obesity, Strategies for preventing obesity. BMJ 2006;333:959-62.

About

Dr. Ralph Rogers MD PhD MBA
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