nutrition ch9

Eating Disorders in Athletes

Athletes and dancers are at risk for suffering from an eating disorder, especially in sports where weight is important (e.g., swimming, gymnastics, figure skating, wrestling, etc.). When athletes have an eating disorder, this often ends up negatively affecting their athletic performance due to reduced strength and endurance.

Anthropometry

Direct body measurements (e.g. waist circumference, fat fold test).

Drawbacks to BMI:

Fails to show how much weight is actually fat 2. Fails to show where the fat is located (we will see why this is important in this unit) 3. It is not suitable for certain groups: i) Some athletes: because muscle mass weighs more then fat. Therefore, athletes may have a higher BMI, although their total body fat may be quite low (e.g., body builders - their BMI is often in the obese range) ii) Pregnant and lactating women: increased weight is normal during childbearing iii) Adults over 65: BMI values are based on data collected from younger people. Also, people tend to lose height as they age. Adjusted BMI ranges for older adults exist with normal BMI ranging from 23-29.

Visceral Fat

Fat stored in the abdominal cavity associated with an increased risk of disease (e.g. CVD, diabetes, stroke, hypertension).

Combating Eating Disorders

For combating eating disorders, a multidisciplinary team approach is best (including doctors, nurses, psychiatrists, dieticians, family therapists

Genetics in obesity

Genetic makeup greatly influences how efficiently our body uses and stores energy. There are a few types of obesity that are fairly rare, and are primarily as a result of genetic causes. However, in a majority of cases of obesity, genetics may cause a tendency towards obesity; however is not the only determinant.

The maximum recommended body fat is:

Men under 40 years: 22%, over 40 years: 25% • Women under 40 years: 32%, over 40 years: 35%

Fasting

Rapid initial weight loss (typically water weight) and loss of lean body mass. Weight is quickly regained upon resuming eating, as BMR has been lowered due to loss of lean muscle mass. Current research shows no benefits for long term weight loss.

outside the body factors in obesity

Research shows that many people have a tendency to over-consume when presented with a wide variety of food, especially delectable items like sweets, snacks, condiments, and main dishes.

Bulimia Nervosa

Those who suffer from this often suffer in silence because they are usually close to ideal body weight.

Very Low Calorie Diets

Typically less then 1,000 calories per day. It is difficult to meet DRI recommendations when consuming so few calories. Weight loss will occur, but is usually accompanied by loss of lean body mass. These diets are very hard to follow and are usually not used unless doctor or hospital supervised.

Binge Eating Disorder

Up to half of all people who restrict their food intake to lose weight binge without purging periodically. Binge eating disorder is similar to bulimia, however rarely are purging or compensatory behaviors used. The binge also tends to be lower in calories then the binge seen in bulimia. After a person binges, they still feel guilty, out of control, embarrassed and depressed.

Consumer Corner: High Protein - Low Carbohydrate Diets

Weight loss is usually due to water loss and lowered calorie intake. These diets typically restrict a number of foods (grains, milk, fruit, starchy vegetables), and when a person returns to eating normally after losing weight on a high protein, low carbohydrate diet, they typically re-gain weight at a fast rate (faster than those who lose weight on a low-fat, low-calorie mixed diet). Those following high protein, low carbohydrate diets tend to lose weight more quickly initially, but by 12 months of being on the diet, weight loss has stabilized to be the same as those following a low-fat, low-calorie mixed diet.

Treatment of anorexia nervosa

can be difficult, as many sufferers to not believe that they have a problem or need treatment. A multi-disciplinary approach is needed to address both the food and weight issue, and the relationship issues (with oneself and the family).

Three other methods of estimating body fatness are

(1) density, (2) conductivity, and (3) radiographic techniques.

We need three lifestyle components to achieve a healthy body weight:

(1) diet, (2) physical activity, and (3) behavior modification.

Characteristics of bulimia nervosa

recurring episodes of binge eating combined with a morbid fear of becoming fat. This is usually followed by: a. Purging:self-induced vomiting or abuse of laxatives, diuretics, enemas OR b. Non-purging: fasting, excessive exercise.

Satiation

s the perception of fullness that builds throughout a meal, eventually reaching the degree of fullness/satisfaction that stops eating. Satiation generally determines how much food is consumed in one sitting.

Healthy weight loss is

slow weight loss, aiming for 1-2 lbs per week. Studies show that it is easier to sustain slow weight loss.

When energy intake is less than energy expended

the body can draw on these fat stores. Therefore, to lose one pound of body fat, you must expend 3,500 calories more then you consume.

Anorexia nervosa typically affects

women, however approximately 1-2 of every 20 cases affect men. Most individuals who suffer from anorexia have these characteristics in common: • they are from middle or upper class families • they are perfectionists • their parents tend to be critical and often exert a lot of pressure on the child • the individual is very disciplined (for example, they often memorize calorie charts).

overeating occurs when

emotional reasons; boredom, loneliness, sadness, happiness.

When energy intake exceeds energy expenditure

excess fat accumulates in the fats cells. For each 3,500 calories that you eat in excess of expenditure, you store approximately one pound of body fat.

behaviour modification

focuses on taking a look at the cues that are causing behaviours that are resulting in consequences. E.g. Sitting in front of the TV is the cue causing the behaviour of eating chips which is resulting in weight gain (the consequence). In this case, we need to change the cue and the behaviour to change the consequence. Some cues need to be eliminated, some suppressed if they cannot be eliminated (e.g. if going to a party where food will be served, avoid standing right beside the food table). Other cues need to be strengthened or reinforced if they are resulting in positive behaviours (e.g. keeping a pair of running shoes at work so that you can go for a walk on your lunch hour).

Radiographictechnique

giveimagesofbodytissuesandanassessmentof body composition. An example is dual energy X-ray absorptiometry (DEXA), which measures two beams of x-ray energy as they pass harmlessly through body tissue. These beams differentiate between fat-free soft tissue, fat tissue and bone tissue. Therefore they provide a precise measurement of total body fatness and the distribution of the fat. Disadvantages are that it is very expensive, and it may not represent an accurate picture in extremely obese individuals - body fatness may be overestimated in those with a thick body shape.

Foods that people binge on are

high fat, high carbohydrate, low fibre foods (e.g., cake, cookies, ice cream). A typical binge would occur in private and often contains thousands of calories, and a person feels a loss of control during the binge. After a person binges, they feel guilty, out of control, embarrassed and depressed.

Hunger

is a physiological need to eat. It is an unpleasant sensation that demands relief, a drive to obtain food. a much more powerful stimuli that satiety and protein is the most satiating of the nutrients.

Appetite

is a psychological desire to eat. It is a learned motivation and a positive sensation that accompanies the sight, smell or thought of appealing foods.

Unsound Approaches for Weight Loss

1 Fasting 2 Very Low Calorie Diets 3 Consumer Corner: High Protein - Low Carbohydrate Diets

factors of body fat amounts

1. Competitive endurance athletes may have lower body fat than average.They need just enough body fat to provide fuel for their activity, insulate the body and allow for fat-soluble hormone activity. 2. Northern fishermen want higher body fat to insulate against the cold. 3. During pregnancy the outcome can become promised if a women starts pregnancy with too much or too little body fat. If body fat is too low, some individuals become infertile, and some individuals with high body fat also have difficulty getting pregnant.

In females, three medical problems make up the female athlete triad:

1. Disorderedeating 2. Amenorrhea(lossofmenstruation) 3. Osteoporosis(remembertherolethatsexhormoneestrogenplayedinbone health).

Anorexia nervosa is characterized by:

1. Refusal to maintain a minimally normal body weight. Usually individuals are less than 85% of a minimal ideal body weight. They also have an intense fear of being fat (even though they are underweight) 2. Self-starvation to the extreme. This often results in amenorrhea (loss of menstruation) in female sufferers. 3. Disturbed perception of body weight and shape. Individuals see a different picture in the mirror (they do not see themselves as being thin, but rather view themselves as being "fat").

There are 2 types of anorexia nervosa:

1. Restricting type (severely restrict calorie intake) 2. Binge eating/ purging type: regularly engages in binge eating or purging behaviors (such as self induced vomiting, misuse of laxatives, diuretics, enemas) We often link binging to bulimia, however those with anorexia can also exhibit binging behaviors. The biggest difference though is that those with anorexia are underweight.

The minimum calorie level typically recommended is

1200 calories per day for women, 1500 calories per day for men. Below this calorie level, it becomes difficult to meet the DRI recommendations for nutrients.

Density

a measure of body weight compared to volume. Lean tissue is denser than fat, therefore, the denser a person's body is, the more lean tissue it must contain. Density can be determined either by underwater weighing or by air displacement methods.

Leptin

is an appetite suppressing hormone that is produced in the fat cells. conveys information about body fatness to the brain, working to suppress appetite and food intake between meals. Some is also produced in the stomach. As body fatness increases, more leptin is produced in an attempt to lower food consumption and result in fat loss. When body fatness decreases leptin production decreases and appetite increases.

Satiety

is the perception of fullness that lingers after a meal, inhibiting eating until the next meal. Satiety generally determines the length of time between meals.

Body Mass Index (BMI)

is used to evaluate a person's health risks associated with being underweight and overweight. The calculation for BMI is your weight in kg divided by your height in meters squared (to convert lb to kg - divide wt in lbs by 2.2. To convert ht in inches to ht in cm, multiply ht in inches by 2.54). BMI = weight in kg/(height in m)2

Conductivity

measures the body's ability to conduct an electric current.Only lean tissue and water conduct electrical current. Bioelectric impedance (BIA) measures how well a tiny, harmless electrical charge is conducted through the body. The idea is that the charge will conduct better in a body with more lean tissue. A disadvantage is that fluctuations in the body's water content can impact results. Water conducts electrical charge, so over hydration can underestimate body fatness, and dehydration can overestimate body fatness.

at fold test

measures the thickness of a fold of skin at areas on the body using calipers. Often the back of the arm, below the shoulder blade or skin from the waist is tested and compared to standards.

Waist circumference

measures visceral fatness and disease risk. You measure around the body at a point near the belly button. The person should exhale normally when the measurement is taken. A higher waist circumference can indicate an increased risk of disease even if BMI is normal. • Healthy waist circumference: less then 102 cm or 40 inches for males and less then 88 cm or 35 inches for females