Pyramid Science

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Saturday, December 27, 2008

Eating Disorder

Losing Weight

Rapid weight loss can result in excessive loss of lean tissue and reduction in aerobic capacity, strength, muscle endurance and dehydration. Prolonged dieting or food restriction can lead to menstrual irregularities and amenorrhea, reduced testosterone production in men and increased risk of stress fractures and bone loss (osteoporosis), chronic fatigue and disordered eating. Safe weight loss may be achieved by maintaining a high carb diet (60%), an adequate protein intake (15-20%) and a low fat intake (15-25%), together with an appropriate excercise programme. Recommended weight loss is 0.5-1kg/week so to make the weight for competition, it is essential to set a realistic goal and allow sufficient time to achieve it. High carb/low fat diet is the key to appetite control and long term weight management. The basal metabolic rate (BMR) is proportional to body weight, though there is no evidence that the BMR is reduced in overweight people. Food restriction causes only a temporary reduction in BMR, but this may be offset by exercise and, in any case, is restored once normal eating is resumed. Yo-yo dieting leads to a loss of lean tissue and an increased risk of heart disease and there is no permanent effect on BMR.

Gaining weight

Gaining weight involves a combination of strength training and a balanced diet. The rate of any weight gain depends on genetics, body type and hormonal balance. On average, a lean weight gain of 0.5-1kg/month is recommended and to gain muscle strength and size, there must be a slight positive energy balance. A recommended protein intake should range between 1.4-1.7g/kg.

Disordered eating

Disordered eating patterns are increasingly common among athletes and fitness participants and up to an estimated 62% female athletes may be affected. This is characterised by the preoccupation with food, food restriction and poor body image. It is regarded as a sub-clinical eating disorder as it includes some, though not all, of the criteria for defining a clinical eating disorder such as anorexia nervosa and bulimia nervosa. Athletes share many of the same personality characteristics as people with clinical eating disorders:
  • Obsessiveness
  • Compulsiveness
  • Perfectionism
The sports most 'at risk' include endurance sports (leanness is believed to be an advantage for performance), aesthetic sports (leanness is believed to be an important judging criterion in competition), and weight category sports. Many sports people appear to have a distorted body image and a higher level of body dissatisfction than the general population. There is no single cause of clinical or sub-clinical eating disorders, though it is likely that certain sports may precipitate an eating disorder in predisposed people, rather than be the cause of the eating disorder. Health consequences of disordered eating include chronic fatigue, reduction in performance, susceptibility to infection and injury, menstrual irregularities, amenorrhea, increased risk of stress fractures and osteoporosis. Sufferers should be approached with tact and sensitivity, rather than be guided towards professional help by an eating disorders specialist or counsellor.

Into practice

If "eating on the run", take a supply of healthy snacks to consume at regular intervals and an "eating on budget" diet should be around basic nutritious foods such as cereals, pulses, starchy vegetables and milk. Fruit and vegetables should be bought in season and in bulk. If there is little time to prepare meals they should be cooked in larger quantities and the remainder saved (frozen). Plan a weekly menu in advance and if eating late at night, consume most food during early part of day. A moderate-sized high carb snack/meal is then beneficial in the evening after training. A well-planned vegetarian diet can provide all the nutrients needed by athletes for good health and performance. Vegans may need to use more fortified foods. Female athletes may be at greater risk of deficient intakes of iron, calcium, riboflavin and folic acid, due to their lower intakes of food generally. The pre-competition diet should be high in carbs to ensure full glycogen stores. Include plenty of fluids to ensure good hydration. This meal should be taken 3-4hrs beforehand and be high in carbs, low in fat and fibre and easy to digest. Consuming an additional 50g high GI carb immediately before competition may delay fatigue in events lasting more than 1hr. Performance in events lasting >90mins may be increased by consuming 30-60g carb/hr in solid or liquid form.


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