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Unit 5

Nutrition and Label Reading

Good nutrition?

Food that:

  1. Meets your physical needs for energy and nutrients
  2. Maintains or improves your energy balance
  3. Is enjoyable

Food: Our Energy Source

Calorie
kilocalorie (kcal), the amount of heat necessary to raise 1 kg of water 1 degree centigrade
Empty Calories
calories in foods which are high in fat and sugar content but lack any significant amount of vitamins and minerals
Caloric Density
the relative number of calories per unit of weight
Nutrient Density
the relative amount of vitamins and minerals a food provides relative to its caloric content

Nutrients for a Healthy Body

Nutrients
the substances the body requires for energy, and for structural and regulatory purposes
  • Macronutrients:
    • water
    • carbohydrates
    • fats
    • protein
  • Micronutrients:
    • vitamins
    • minerals

Water

  • 50-60% of total body weight
  • involved in transport, reactions, thermoregulation
  • intake ensures hydration
    • normal daily H2O loss = 2 to 2.5 quarts
  • soft drinks, beer, coffee cause diuresis

Carbohydrates

Essential for general metabolism and especially brain function

Supplies 4 calories for each gram of carbohydrate.  This information is helpful in determining what percentage of your daily caloric intake comes from carbohydrates.

  • Complex carbohydrates
    • starch (pasta, bread, potatoes)
  • Simple carbohydrates
    • sugar (table sugar, fruit sugar)
  • Fiber
    • grains, fruit, vegetables
  • Dietary goal
    • 55-60% of total calories
  • Typical American diet
    • 40-45% of total calories
  • Eat 5-9 servings fruits & veggies per day, and 6-11 servings breads & cereals

Fiber

  • Soluble
    • Barley, oats, legumes, sweet & white potatoes
    • Positive effect on blood cholesterol levels
    • May lower heart disease risk
  • Insoluble
    • Vegetables, whole wheat, wheat bran
    • “Drano” effect
    • Protective for colon cancer

Fats (lipids)

Concentrated Energy!  Supplies 9 calories for each gram of fat, regardless of the source of fat.  This information is helpful in determining what percentage of your daily caloric intake comes from fats.  You may also wish to calculate what percentage of your caloric intake comes from saturated fats, as they contribute to heart disease by increasing cholesterol levels.

Fatty acids

  • saturated
    • elevates blood cholesterol
  • monounsaturated
    • one double bond
  • polyunsaturated
    • more than one double bond

Fat Facts

  • Trans fatty acids
    • Increase heart disease risk, margarines, partially hydrogenated soybean oil
  • Omega-3 fatty acids (fish oil)
    • protective
  • Essential for: cell membranes, steroid hormones, absorption of some vitamins
  • Too little fat = vitamin deficiency, impaired hormone function
  • Excess fat in the diet: stored as body fat

Dietary goals

  • < 30% of total calories
  • < 10% of fat from saturated and trans fatty-acid sources combined

Typical American diet

  • 35-40% of total calories
  • Major sources: meat, fish, poultry, dairy, oils

Cholesterol

  • Form of dietary fat, also synthesized by our bodies
  • Structural component of cell membranes, precursor to steroid hormones
  • Sources: only in animal products meat, milk, eggs, liver, shellfish

Protein

Supplies 4 calories for each gram of protein, just like carbohydrates.  This information is helpful if you are interested in what percentage of your daily caloric intake comes from proteins.

  • Composed of 20 different amino acids, 9 are essential
  • Functions
    1. Structural - component of cells (body tissues: muscles, bones, blood, hair)
    2. Regulatory - forms enzymes which regulate metabolism reactions, immune system
    3. Energy providing - used to make ATP
  • Dietary goal: 12-15%
    • animal sources contain complete proteins
    • eating complementary plant proteins provide complete protein
  • Sources: egg whites, milk, fish, beef, beans, peas, peanuts

Complementary Proteins

  • legumes (peanuts, beans, lentils, peas) + grains (wheat, rice, corn)
  • Peanut butter sandwich
  • Bean & rice burrito
  • Hummus (garbanzo beans + sesame seeds)

A little Exercise in Nutrition

  • Total dietary intake of 2400 calories
  • Goal:
    • Carbohydrates  at 55 %
      • 2400 x .55 = 1320 kcal / 4 kcal = 330 grams
    • Proteins at 15%
      • 2400 x .15 = 360 kcal / 4 kcal = 90 grams
    • Fats  at <30%
      • 2400 x .30 = 720 kcal / 9 kcal = 80 grams

Nabisco product nutrition labelInterpreting Food Labels

  • new labels must contain certain information
  • serving sizes are more realistic - be sure to check closely
  • “fat free” means < 0.5 g fat/serving
  • “low fat” means < 3 g fat/serving

Calculating Macronutrients

Use the Wheat Thins label at the right and the calculations below to see how easy it is to assess important nutritional information from food labels.

  • Calories from Fat:
    • 6g x 9 kcal/g=54 kcal
    • 54 kcal/140kcal=39%
  • Calories from Carbohydrate:
    • 19g x 4 kcal/g=76 kcal
    • 76 kcal/140kcal=54%
  • Calories from Protein:
    • 2g x 4 kcal/g=8 kcal
    • 8 kcal/140kcal= 6%

How does this snack cracker fit into our guidelines for fat intake?

Is this food a good source of protein?

What might be a better choice for a snack cracker?

 

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