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51 Cards in this Set

  • Front
  • Back

Early adolescence

11-14 years

Middle adolescence

15-17 years

Late adolescence

18-21 years (crosses over with early adulthood)

Nutritional Needs

  • Substantial physical, emotional and cognitive maturation
  • Rapid physical growth affects nutrient needs
  • strong desire for independence: can influence food choices

Physical Development

Puberty begins during the Early Adolescence - biological changes of puberty include:

  • increase in height and weight
  • sexual maturation
  • changes in body composition
  • accumulation of skeletal mass
  • order of changes is consistent, but the timing is not!

Physical Development

  • Variations in reaching sexual maturity affect nutrition requirements of adolescents
  • sexual maturation (also called biological age)- not chronological age- should be used to assess nutritional needs

Sexual Maturation Rating

Sexual Maturation Rating (SMR, also called "Tanner Stages"): Scale to assess degree of sexual maturation - Rated on a 5 point scale (SMR 1-5):

  • SMR Stage 1 = pre-puburtal growth and development
  • SMR Stages 2-5 = occurrences of puberty
  • SMR Stage 5 = sexual maturation has concluded

Sexual Maturation Rating

  • Boys: genital development and pubic hair growth
  • Girls: breast development and pubic hair growth
  • Evaluation of SMR can be completed by a physician or adolescents can rate themselves

Sexual Maturation in Females

  • Menarche: onset of first menstrual period
  • Occurs 2-4 years after initial development of breasts (SMR 4)
  • Age of menarche ranges from 10-17 years (avg 12.4 yrs)
  • Peak velocity of linear growth occurs ~6 to 12 months prior to menarche (SMR 3)
  • In highly competitive athletes, severly restrictive diets may delay or slow growth

Body Composition Changes in Females

  • Peak weight gain follows linear growth spurt by 3 to 6 months
  • Increase in body fat
  • Decrease in lean body mass from 80% to 74% of body weight

What percentage of body fat increase happens during puberty for females?


Body Fat Levels in Females

  • Low: <20%; Moderate: 28%; high/obese: >35%
  • 17% body fat is required for menarche to occur
  • 25% body fat needed to maintain normal menstruation cycles (ovulation)

Sexual Maturation in Males

  • Large variation in chronological age at which sexual maturation takes place
  • Peak velocity of linear growth occurs during SMR 4 and ends with the appearance of facial hair
  • Linear growth continues throughout adolescence at a slower rate until ~ 21 years

Body Composition Changes in Males

  • Peak weight gain at the same time as peak linear growth
  • Peak weight gain, ~20 lbs/year
  • Body fat decreases to ~12%

Skeletal Mass

  • ~Half of bone mass is accrued in adolescence
  • By 18: 90% of skeletal mass is formed

Energy needs are influenced by:

  • activity level
  • basal metabolic rate (BMR)
  • pubertal growth and development

Level of physical activity...

declines during adolescence resulting in reduced energy requirements

Energy Ranges:

  • Males: 2200-3100 kcal/day
  • Females: 2000-2400 kcal/day

Calculating Estimated Energy Requirements

Boys 9-18 years:

EER = 88.5 - (61.9 x age) + PA x{26.7 x weight[kg] + (903 x height[m])} + 25

Girls 9-18 years:

EER = 135.3 - (30.8 x age) + PA x{10.0 x weight[kg] + (934 x height[m])} + 25

Calculating Estimated Energy Requirements

  • Age in years, weight in kilograms, height in meters
  • Physical activity (PA) according to chart

Acceptable Macronutrient Distribution Range (AMDR)

The range of intake for a particular energy source (protein, fat or carb), expressed as a percentage of total energy (kcal), that is associated with reduced risk of chronic disease while providing adequate intakes of essential nutrients

Protein Requirements

  • Influenced by amount needed to maintain existing and lean body mass and develops new muscle
  • DRI: 0.85 g/kg body weight (AMDR: 10-30%)

Low protein intakes during adolescence linked to:

  • reductions in linear growth
  • delays in sexual maturation
  • reduced lean body masses

Carbohydrate and Fibre

Carbohydrates: 130 g/day or 45-65%

Dietary Fibre:

  • Males: 9-13 years - 31 g/day
  • Males: 14-18 years - 38 g/day
  • Females: 9-13 years - 26 g/day
  • Females: 14-18 years - 26 g/day

Dietary Fat

  • Required as dietary fat and essential fatty acids for growth and development
  • 25-35% E from total fat
  • 0.6-1.2% E from omega 3 fatty acids (LA, ALA)
  • <10% E from saturated fats


  • AI is critical to ensure peak bone mass
  • Absorption highest for females around menarche, for males during early adolescence
  • ~4 times more calcium absorbed during early adolescence compared to adulthood
  • Adolescents who do not include dairy should consume calcium-fortified foods
  • Soft drink consumption displaces nutrient-dense beverages such as milk and fortified juices
  • RDA for 9-18 years is 1300 mg/day

Vitamin D

  • Facilitates intestinal absorption of calcium (and phosphorus)
  • Essential for bone formation
  • synthesized by the body via skin exposure to (UV B rays of) sunlight
  • In northern latitudes, may require supplementation
  • DRI: 600 IU per day
  • Indigenous people are at risk for low exposure, diet not always inclusive, many are lactose intolerant


  • Rapid rate of linear growth and increase in blood volume
  • For females, needs highest after menarche (15 mg/day)
  • For males, after growth spurt (11 mg/day)
  • Deficiencies in 9% of 12-15 year old females and 5% of 12-16 year old males


Needed for sexual maturation and growth, especially in males

B Vitamins

  • Folate, Vit B12, niacin, riboflavin, thiamin
  • requirements are double those of elementary school age

Selected Nutrient Intakes from Canadian Community Health Survey (CCHS)

  • Caloric intakes are high for both sexes
  • Neither sexes have good intake of fibre
  • Fat intakes are high
  • Low Vit D and Calcium intakes for females
  • Sodium intake is very high, especially for males (at risk for hypertension, high blood pressure, etc.)

The Teen Brain

  • ability to reason, rational thought may be limited
  • live in the moment; limited consideration of long-term consequences
  • reward benefits are more important than possible risk

The Teen Brain - video

  • considered a late childhood brain
  • still at peak learning; can imprint/memorize
  • connectivity of brain develops from back to front
  • last place is frontal lobe via mylenation (key for insight and judgment)
  • Teens are very sharp by not great at judging

Social and Emotional Development in Early Adolescence

  • Strong need for social acceptance from peers
  • Body image may change as a result of changes in body shape
  • Increased awareness of sexuality
  • Strong sense of impulsivity

Social and Emotional Development in Middle and Late Adolescence

  • Increased opportunities for employment and outside activities
  • Greater autonomy from parents
  • Continued need for social acceptance from peers
  • Increased awareness of social and moral issues

Vegetarian Diets During Adolescence

About 4% of adolescents report being vegetarian

Reasons being:

  • cultural or religious beliefs
  • moral or ethical concerns
  • health beliefs
  • to restrict fat and/or calories
  • a means of independence from family

Vegetarian Eating Habits

  • 2516 US adolescents, age 15-23
Compared to non-vegetarians, vegetarians had:
  • better Fruit and Veg intake, less overweight/obesity
  • more eating disorders, more weight controlling behaviour

Dietary Guidance

  • No specific guidance from Health Canada
  • Lacto-ovo vegetarians can meet needs following EWCFG by:
  • Choosing legumes, nuts, tofu as alternatives to meat; fortified soy beverage as milk alternative
  • For Vegans, EWCFG will not be adequate
  • Need for animal-derived foods to supplement: Calcium, zinc and Vitamins D, B6 and B12

Position of Dietitians of Canada on Vegetarian Diets (2003)

  • Depends on level of restriction; too much restriction, there is a concern with adequacy especially for growing children and adolescence
  • can be associated with eating disorders
  • fortification and supplements will help vegans to achieve adequate nutrition

BUT...The teen brain

Ability to plan and problem solve may be limited

  • Teens can be supported and educated by parents and caregivers
  • If teens are motivated by weight loss, caregivers need to try to understand these motivations

Physical Activity Guide for Children 5-17

  • 60+ min/day of moderate to intense exercise
  • 3+ days/week, intense exercise
  • 3+ days/week, muscle building exercise

Health Behaviour in School-aged Children Study

  • Trend shows that physical activity decreased as grades increased (Grade 6-10)
  • Females were less active than males in general

Physical Activity CCHS

  • 80% of adolescents not doing ANY daily physical activity
  • 14% use the computer more than 10 hours a day

Association between body satisfaction and weight-related behaviours


  • Increase in extreme weight control behaviours
  • Increase in binge eating
  • Decrease in physical activity
  • Decrease in Fruit and veg intake
  • Increase in extreme weight control behaviours
  • Increase in binge eating
  • Decrease in physical activity

Eating Disorders

Three clinically defined/diagnosed:

  • anorexia nervosa
  • bulimia nervosa
  • binge eating disorder

Continuum of eating concerns and disorders

Body dissatisfaction -> dieting behaviours -> disordered eating -> clinically significant eating disorders

Some Canadian Statistics

  • (2000) 46% of girls and 26% of boys report being dissatisfied with their body shape/size
  • 48% of 15 year old girls dieting to lose weight (1992)
  • 27% of Ontario girls 12-18 years report disordered eating behaviours (vomiting, fasting, laxative use) (2001)

Key features of anorexia nervosa

  • Refusal to maintain body weight at normal weight for age
  • Intense fear of gaining weight
  • amenorrhea
  • distorted body image

Key features of Bulimia nervosa

  • recurrent episodes of rapid consumption of a large amount of food in a discrete period of time
  • use of laxatives or diuretics

Binge Eating Disorder (BED)

Binge eating, not followed by compensatory behaviours (2% of general population, 30% of dieting population)


  • Dietary restrictions leading to uncontrolled hunger
  • role of food in their life: comfort, support, deal with stress, to feel numb,etc.

Why In Adolescence?

Life is overwhelming:

  • many changes (physical, mental)
  • struggling for own identity and independence
  • Increased pressure: socially, academically, emotionally
Searching for control over stress

  • food consumption and body weight can be controlled even when other things cannot