Part of the food is converted into our living flesh as building blocks for cellular molecules and structures, as wells as to replace worn out parts.

Most foods are used as metabolic fuels. They are oxidized and transformed into

ATP.

The energy value of foods is measured in units called kilocalories (kcal) or “large calories (C)” the units counted by dieters.

A nutrient is a substance in food that is used by the body to promote normal growth, maintenance, and repair.

The major nutrients:1. Carbohydrates2. Lipids3. Proteins4. Vitamins5. Minerals6. Water (60% of the volume of the food we eat)

With the exception of Lactose and a small amount of glycogen from meat, all other carbohydrates we eat come from plant products.

Fiber – cellulose; plentiful in most vegetables; not digestible by humans; increases the bulk of the stool and aids in defecation

Most are dietary neutral fats – triglycerides

Saturated fats from animal products such as meat and dairy products, and coconut

Unsaturated from seeds, nuts, and plant oils

Cholesterol from egg yolk, meats, and milk products

Highest quality (complete proteins) comes from animal products

Incomplete proteins – legumes, nuts, cereals

Cereal grains and legumes ingested together provide all the essential amino acids (rice and beans)

Organic nutrients of various forms that the body requires in small amounts

No one food contains all the required vitamins

A, C, E appear to have anticancer effects

Most vitamins function as coenzymes (work with an enzyme to perform a particular function)

The body also requires adequate supplies of seven minerals (inorganic substances)

1. Calcium2. Phosphorus3. Potassium4. Sulfur5. Sodium6. Chloride7. MagnesiumThe most mineral rich foods are

vegetables, legumes, milk, and some meats. Fats and sugars have practically no minerals.

• This table lists foods that contain fat-soluble and water-soluble vitamins.

VitaminsFat-soluble

Function Source

A Maintain health of epithelial cells; formation of light absorbing pigment; growth of bones and teeth

D Absorption of calcium and phosphorus in digestive tract

E Formation of DNA, RNA, and red blood cells

K Blood clotting

Liver, broccoli, green and yellow vegetables, tomatoes, butter, egg yolk

Egg yolk, shrimp, yeast, liver, fortified milk; produced in the skin upon exposure to ultraviolet rays in sunlightLeafy vegetables, milk, butterGreen vegetables, tomatoes, produced by intestinal bacteria

VitaminsWater-soluble

Function Source

B1Sugar metabolism; synthesis of neurotransmitters

B2 (riboflavin) Sugar and protein metabolism in cells of eyes, skin, intestines, blood

Niacin Energy-releasing reactions; fat metabolism

B6 Fat metabolism

Ham, eggs, green vegetables, chicken, raisins, seafood, soybeans, milk Green vegetables, meats, yeast, eggs

Yeast, meats, liver, fish, whole-grain cereals, nutsSalmon, yeast, tomatoes, corn, spinach, liver, yogurt, wheat bran, whole-grain cereals and bread

Minerals and vitaminsMinerals and vitamins

VitaminsWater-soluble

Function Source

B12Red blood cell formation; metabolism of amino acids

Pantothenic acid Aerobic respiration; synthesis of hormones

Folic acid Synthesis of DNA and RNA; production of red and white blood cells

Biotin Aerobic respiration; fat metabolism

Liver, milk, cheese, eggs, meats

Milk, liver, yeast, green vegetables, whole-grain cereals and breadsLiver, leafy green vegetables, nuts, orange juiceYeast, liver, egg yolk

C Protein metabolism; wound healing

Citrus fruits, tomatoes, leafy green vegetables, broccoli, potatoes, peppers

Minerals and vitaminsMinerals and vitamins

Group Example Foods By all groups Some groups

Fruits Apples, bananas, dates, oranges, tomatoes

Carbohydrates

Water

Vitamins: A,C, folic Acid

Minerals: iron, potassium

Fiber

Vegetables Broccoli, cabbage, green beans, lettuce, potatoes

Carbohydrates

Water

Vitamins: A, C, E, K, and B vitamins except B12

Minerals: calcium, magnesium, iodine, manganese, phosphorus

Fiber

Group Example Foods By all groups Some groups

Grain Products

(preferably whole grain; otherwise, enriched or fortified)

Breads, rolls, bagels, cereals, dry and cooked pasta, rice, tortillas, pancakes, crackers, popcorn

Carbohydrates

Proteins

Vitamins: Thiamin (B1), niacin

Water

Fiber

Minerals: iron, magnesium, selenium

Milk Products Milk, yogurt, cheese, icecream

Protein

Fat

Vitamins: riboflavin, B12

Minerals: calcium, phophorus

Water

Carbohydrates

Vitamins: A,D

Meats and Meat alternatives

Meat, fish, poultry, eggs, seeds, nuts, nut butters, soybeans, tofu, other legumes (peas & beans

Protein

Vitamins: niacin, B6

Minerals: iron, zinc

Carbohydrates

Fat

Vitamins: B12, thiamin (B1)

Water

Fiber

When energy intake and energy outflow are balanced, body weight remains the same.

When not, weight is either gained or lost. Researchers believe that several factors –

1. rising and falling blood levels of nutrients (glucose & amino acids)2. Hormones (insulin, glucagon, and leptin)3. Body temperature (rising is inhibitory)4. Psychological factors

-- have an affect on eating behavior through feedback signals to the brain.

The amount of energy used by the body is measured in kilocalories.

The basal metabolic rate (BMR) is the amount of heat produced by the body per unit of time when it is under basal conditions – at rest. (energy needed to perform essential life activities)

An average 70-kg (154 lb.) adult has a BMR of about 60 to 72 kcal/hour.

Factors Variation Effect on BMRSurface Area Large surface area in relation to body

volume, as in thin, small individuals

Small surface area in relation to body volume, as in large, heavy individuals

Increased

Decreased

Sex Male

Female

Increased

Decreased

Thyroxine production Increased

Decreased

Increased

Decreased

Age Young, rapid growth

Aging, elderly

Increased

Decreased

Strong emotions (anger or fear) and infections

Increased

BMR for Males = 66 + (6.23 x weight in pounds) + (12.7 x height in inches) – (6.76 x age in years)

BMR for Females = 655 + (4.35 x weight in pounds) + (4.7 x height in inches) – (4.7 x age in years)

Total amount of kilocalories the body must consume to fuel all ongoing activities.