2. What is
energy?
Energy: the capacity to do work, such as moving or
heating something.
Calorie: the unit used to measure energy
a kilocalorie is a unit of energy
commonly used to express energy value of food
3. Energy
How we generate Energy from Food
Energy In and Energy Out
Input = Food and Calories
Output = Metabolism (BMR) and Physical Activity
Balance
Weight Maintenance
Weight Increase
Weight Loss
4. The Nutrients in
Foods
Nutrients: substances obtained
from food and used in the body
to promote growth, maintenance,
and repair.
Essential nutrients: nutrients
that must be obtained from food
because the body cannot make
them for itself.
Nonessential nutrients:
nutrients that the body needs,
but is able to make in sufficient
quantities when needed; do not
need to be obtained from food.
7. Calorie Values
Calorie value of carbohydrate, fat, and protein…
If you know the number of grams of carbohydrate, fat, and protein in a
food, you can calculate the number of calories in it. For example, a deluxe
fast-food hamburger contains about 45 grams of carbohydrate, 39 grams
of fat and 27 grams of protein (see above).
Remember this
number…
8. Percentage of Total Energy Intake
The percentage of your total energy intake from carbohydrate, fat,
and protein can then be determined by dividing the number of
calories from each energy nutrient by the total calories, and then
multiplying the result by 100.
9. Components of Energy Output
We Need Energy for:
Basal Metabolism
BMR = Basal Metabolic Rate
Physical Activity
Metabolizing Food
10. Calories and Energy
Balance –
Calories IN = Calories OUT Maintain Weight
Calories IN > Calories OUT GAIN Weight
Calories IN < Calories OUT LOSE Weight
To maintain a desirable weight, energy
intakes should not exceed energy needs.
11. It’s all about Calorie Balance
If you eat more calories than your body uses,
they will be stored as fat
One pound of body fat is equal to 3,500 kcal
In theory, losing one pound requires a deficit of
3,500 Calories
Eating 500 fewer Calories per day - or
expending 500 more Calories - would result in
losing one pound per week
12. Input &
Output
Example
Intake:
3,400 kcal
Output:
3,005 kcal
IMBALANCE:
395 kcal
Eating Breakfast
20 min.
At the Gym
40 min.
Coffee Break
10 min.
Sitting in Class
180 min.
Walking to
Campus
20 min.
Dressing/
Washing
20 min.
Walking on
Campus
30 min.
Snack
10 min.
Lirary/Study
180 min. Eating Lunch
30 min.
Walking Home
20 min. Eating Dinner
30 min.
Check email
30 min. Driving to-from
Date
30 min.
Sleep 71/2
hours
Dancing
40 min.Eating Snack
20 min
Hanging out
with Date
120 minEmailing/Texting
Studying
120 min
Undress/Shower
30 min
650
50
50
100
270
210
25
150
250
25 395
700
75
200
280
100
75
1200 65
55
400
390
50
180
260
105
490
Walking to-from
Campus
30 min.
A day in the life…
13. Weight Management:
To maintain body weight in a healthy
range, balance calories from foods and
beverages with calories expended
To prevent gradual weight gain over
time, make small decreases in food and
beverage calories and increase
physical activity
14. Energy Expenditure:
Calorie expenditure depends on:
Weight of person
Type of activity:
○ Length of activity
○ Speed of activity
○ Metabolic rate
From: Ainsworth, BE, et. al. 1993. Compendium of physical
activities: classification of energy costs of human physical
activities. Medicine and Science in Sports and Exercise. 25 (1):
71-80.
15. The ABCs of Eating for Health:
Adequacy:
getting all of the essential nutrients, fiber, and energy
(calories) in amounts sufficient to maintain health
Balance:
eating foods rich in one nutrient while not crowding out
foods that are rich in another nutrient
Calorie control:
control of energy consumption
Moderation:
no unwanted constituent in excess
Variety:
different foods, same purposes, different occasions
16. Contd..
Nutrient dense:
refers to a food that supplies large amounts of nutrients
relative to the number of calories it contains.
The higher the level of nutrients and the fewer the number
of calories, the more nutrient dense the food