Food & Nutrition Test #2

Calculating Calories and Energy Balance

Where does Energy come from?

• Carbohydrates (4 cal/g)

• Proteins (4 cal/g)

• Fats (9 cal/g)

Examples of calculating calories

• Cheerios

  • Carbohydrates (4 cal/g)

    • 20g x 4 cal/g = 80 cals

  • Protein (4 cal/g)

    • 3g × 4 cal/g = 12 cals

  • Fat (9 cal/g)

    • 2g x 9 cal/g = 19 cals

• Soy Milk

  • Carbohydrates (4 cal/g)

    • 8g x 4 cal/g = 32 cals

  • Protein (4 cal/g)

    • 6g × 4 cal/g = 24 cals

  • Fat (9 cal/g)

    • 4g x 9 cal/g = 36 cals

• Orange

  • Carbohydrates (4 cal/g)

    • 21g x 4 cal/g = 84 cals

  • Protein (4 cal/g)

    • 2g × 4 cal/g = 8 cals

  • Fat (9 cal/g)

    • 0g x 9 cal/g = 0 cals

Total Carbohydrates: 196 cals

Total Protein: 44 cals

Total Fats: 54 cals

Grand Total: 294 calories

Nutrient Dense

• Nutrient density refers to the ratio to calories in food

• A food is nutrient dense when it is rich in nutrients in relation to calories

• A food is nutrient poor when it provides little nutritional value in relation to calories

• Nutrient poor foods are often referred to as empty calories which come form sugary & fatty processed foods.

Energy Balance

• Your body uses food for energy but not all the food you eat is used at once

• Energy balance relates to the intake and output of calories

• Negative energy balance = consuming less calories than you burn

• Positive energy balance = consuming more calories than you burn

How Does the Body Use Energy?

BMR (Basal Metabolic Rate)

• BMR = weight (lbs) x 0.4 × 24

Physical activity

Food processing

Definitions

Sedentary (very little physical activity e.g., sit at a desk all day)

Low active (moderate activity everyday e.g., walking to the bus)

Active (some physical activity everyday - at least 2.5 hours per week e.g., exercising, walking home, gym class)

What is 1 Pound of Body Weight?

• 1 pound of body weight is equivalent to 3,500 kcal (kilocalories)

Digestion

Definitions:

• Digestion - the process by which your body breaks down food and nutrients in the food, into simpler substances, blood then carry these simple substances to cells for use in growth, repair, maintenance.

• There are two types:

  • Mechanical - happens as food is crushing and churned ex. chewing

  • Chemical - food is mixed with powerful acids and enzymes (a type of protein produced by cells that cause specific chemical reactions)

Gastrointestinal Tract

GI Tract - a muscular tube leading from the mouth to the anus. It is about 25-30 feet in length.

Sections of the GI Tract:

1. The mouth - Mastication (another word for chewing) is the first step in the digestive process

   1. Enzyme involved - salivary amylase - helps break down the starches in food

2. The Esophagus - (10 inches long) as you swallow, food passes from the mouth to the stomach through this.

   1. Peristalsis - squeezing actions by the muscles in the esophagus, helps move food through the tube.

3. The stomach - protein begins here - when you eat, the stomach produces gastric juices to prepare for digestion.

   1. Gastric Juices - contain hydrochloric acid, digestive enzymes and mucus

   2. Chyme - the mixture of gastric juices

   3. Mucus - a thick fluid that helps soften and lubricate food. Helps protect stomach from acidic juices

   4. Pepsin - the major gastric enzyme that begins to chemically break down protein

4. The Small Intestine

   1. 95% of digestion occurs here

      1. There are 3 sections to the small intestine;

         1. Duodenum (12 inches long)

         2. Jejunum (4 feet long)

         3. Ileum (5 feet long)

   2. Organs associated with the Small Intestine:

      1. Pancreas - secretes bicarbonate, which neutralizes hydrochloric acid coming from the stomach with the partially digested food. Also produces digestive enzymes that break down proteins, fats, and carbohydrates

         1. Proteases - protein

         2. Lipases - fat

         3. Saccharidases - carbohydrates

      2. Liver - produces digestive juice called bile which aids in fat digestion helps disperse fat in water-based digestive fluids

      3. The Gallbladder - stores bile until it is needed for digestive purposes

5. The Large Intestine (Colon)

   1. Little digestion occurs here. Main job is to reabsorb water (chyme is very liquid when it enters the colon — stays for 1-3 days before elimination)

   2. Feces - solid wastes includes mucus, bile pigments, fibre, sloughed off cells from lining of the large intestine, and water

   3. Rectum - end of large intestine

   4. Anal Sphincter - Anus

BODY MASS INDEX (BMI)

Healthy weight is a Body Mass Index between 19 - 24.9 or a body fat percentage of 15-18% for males and 20-25% for females

How to Calculate Your BMI:

Example: Adaline is 125 lbs and 5ft.5 inches tall. What is her BMI?

Step one - convert height to inches: 5ft x 12 = 60 inches, then 60 + 2 = 62 inches

Step two - convert weight to pounds; 125 lbs

BMI FORMULA; BMI = weight ÷ (height)² x 705

BMI = 125 ÷ 62² x 705

BMI = 125 ÷ 3844 × 705

BMI = 0.0325 × 705

BMI = 22.9