Title: Weight Management

Key words: Weight loss, dieting, social factors, obesity, metabolic rate, exercise

Date: July 2000

Category: 9. Weight Management

Type: Article

Author: Dr van Rhijn



Weight Management



The western world is currently obsessed with weight loss. This is very appropriate, as obesity has become one of the most important avoidable causes of ill health globally. Successful weight loss, however, is dependent upon numerous factors, which will be discussed briefly below.


Factors Involved:

Social Factors and the Therapeutic Relationship

The media is saturated with images of "ideal beautiful people" and misinformation about obesity, without supplying the understanding and support necessary for people who are trying to slim, with severe demoralising consequences.


Healthcare professionals and obese patients often fall into a ‘dieting relationship trap’1, where things only go well as long as adequate weight loss has been achieved. Inevitably, when this is not achieved numerous psychological issues such as low self-esteem, self-reproach, unworthiness, apologies, guilt and anger surface, virtually inviting the health carer to discharge them. Understanding, support and encouragement are required, as both parties may have unrealistic expectations about weight loss. Setting simple, clear and realistically achievable short- and long-term goals is essential to prevent disappointment and lack of motivation2.


Changing Eating Patterns

Dieting requires a change from the habitual eating behaviour (where, when and with whom) that has lead to obesity. Having a diet that is acceptable is fundamental to establishing compliance to the new taste and eating pattern. This should be tailored to the individual circumstances, with realistic and attainable weight loss targets.


Energy deficit

The rate of weight loss (fat & lean body mass) is generally proportional to the energy deficit, and the relative contribution of each depends on the initial body fat as well as the size of energy deficit3. Following a strict dietary restriction of 500 calories a day below normal maintenance, a person will lose about 0.5 kg per week and 7 kg in 3 months. The diet must provide the essential nutrients and also set the energy deficit of the diet at between 800 – 1500 kcal/day. Weight loss is initially greater owing to accompanying protein and glycogen breakdown and consequent water loss4. After 3-4 weeks, weight loss slows down, as only adipose tissue is broken down without accompanying water loss.


Individual & Dietary Factors

Individual metabolic rates vary enormously due to genetic, hormonal5 (thyroid), health state, stress and dietary factors. Several macro and micronutrients affect the rate of weight loss. These include essential fatty acids, vitamins, minerals and carnitine which increase the efficiency of oxidation and raise metabolic rate, energy and activity levels. Refined foods are convenient and easier to digest but lead to overeating, whilst proteins have more satiating power than carbohydrates or fats. Drinking plenty of water helps to excrete ketones, prevent dehydration and provide a feeling of fullness. Diet-induced weight loss results in a decrease in plasma leptin concentrations which becomes a potent stimulus to weight gain6.


Environment & Physical Activity

The metabolic rate is affected by the climate, temperature, season and clothing. It is extremely difficult to lose weight simply by increasing exercise and physical activity7 despite increased energy expenditure. Exercise is, however, vital for weight maintenance, to avoid regaining weight and to protect against muscle wasting. Intermittent exercise8 is best as it improves the quality of life and reduces blood lipids, blood pressure and the risk of diabetes.



An individualised approach, with collaboration and motivation is required to attain appropriate weight loss and to maintain a normal weight indefinitely. Achieving this successfully will depend upon a thorough understanding of the factors involved in the slimming process.




1.      Garrow, J.S. & James, W.P. Human nutrition and Dietetics. Ninth Edition.  Churchill Livingstone. 1996; pp. 521 – 533.


2.      Summerbell, C.D. et al. Randomised controlled trial of novel, simple and well supervised weight reducing diets in outpatients. BMJ. 1998; Vol 317;1487 - 1489. 


3.      Ziegler, E. & Filer, L.J. Present knowledge in Nutrition. Seventh Edition.  ILSI Press, Washington DC. 1996; Pp. 445 – 455.


4.      Kumar, P. & Clark, M. Clinical Medicine. 1996; Third Edition. W.B. Saunders Company Ltd.


5.      Rosenbaum, M. et al. Obesity. N. Eng. J. Med. 1997; Vol 336: 396 - 407.


6.      Friedman, J.M. & Halaas, J.L. Leptin and the regulation of body weight in mammals. Nature. 1998; 395: 763 - 770.


7.      Souhami, R.L. & Moxham, J. Textbook of medicine. Third Edition. Churchill Livingstone. 1997.


8.      Tremblay, A. et al. Impact of exercise intensity on body fatness and skeletal muscle metabolism. Metabolism. 1994; 43: 814 - 818.


9.      Obesity and Weight Management: Fact File No 4: National Dairy Council. London. 1993.