Energy Balance

Question 1

What is body image ? What are some influences?

Answer 1

Body image is the perception of how we view our bodies and is often shaped by outside influences such as peers, family, clothing designers and the media.

Question 2

Thin is portrayed by the media but what paradox is unfolding before us?

Answer 2

The world’s population is becoming heavier. In the last two decades there has been an increase in the number of people who are overweight or obese. In 1980 about 5% of men and 8% of women were considered obese. Today about 30% of the population in the United States is considered obese.

Question 3

What is energy balance?

Answer 3

This is defined as energy intake being equal to energy expended. In other words, the number of calories ingested from food and beverages must be equal to the number of calories burned through basic body functions plus exercise.

Amount of energy that you take in is equal to the amount of energy that you use

Question 4

A positive weight balance and its effect

Answer 4

More calories are consumed than expended and over time the excess consumption will lead to weight gain.

Question 5

One pount of fat is equal to how many kilocalories ?

Answer 5

3500 kcal

Question 6

Fat is stored in what type of cells ?

Answer 6

Adipose cells

Question 7

What is hyperplasia?

Answer 7

This is one of the stages that occur in the devlopment of fat cells.

Hyperplasia occurs during periods of growth, such as adolescence of pregnancy, when we increase the number of fat cells in our body.

Question 8

What is hypertrophy?

Answer 8

One of the stages that occur in the devlopment of fat cells-

this occurs in adulthood- while we may still continue to develop cells, it is more likely that the size of the cells will increase.

This is defined as energy intake being equal to energy expended. In other words, the number of calories ingested from food and beverages must be equal to the number of calories burned through basic body functions plus exercise.

Question 9

Negative energy balance and when it would occur……

Answer 9

More calories are expended than are taken in.

This is not desirable and could occur when someone is fighting an illness or trauma that would negatively affect appetite and intake.

In other cases, an extremely high amount of energy is required for healing, such as someone who has suffered a major burn injury. However, for most of the population, being in negative energy balance is an intentional act. Calories are limited and or exercise is increased. The intended result is that over time this would lead to a weight loss.

Question 10

Where does our sole source of energy intake come from ?

Answer 10

Food and beverages

Question 11

Talk about the consumption of a Snickers bar and its efect on energy balance

Answer 11

Eating a readily available Snickers bar would provide you with 280 calories, coming from 14 grams of fat, 35 grams of carbohydrates and 4 grams of proteins.

This intake of 280 calories though means that, in order to prevent weight gain, 280 calories worth of energy must now be expended.

Question 12

Energy expenditure is both ______________ and ____________________

Answer 12

intentional and naturally occuring

We can burn energy in the form of basal metabolism, physical activity, the thermic effect of food and thermogenesis.

Question 13

What are the two major components of energy expenditure ?

Answer 13

Basal metabolic Rate (BMR)

and physical activty

Question 14

What is BMR ?

Generally, what is the difference in BMR in males and females?

What accounts for differences in BMR?

Answer 14

The number of calories used by the body while in a fasting state.

In general, males require 1 kcal/kg/hour and females require 0.9 kcal/kg/hour to support the function of various body organs and to stay alive. The BMR varies per person based on a number of factors such as; gender, lean body mass, body size, temperature, age, nervous system activity, caffeine and smoking.

Pregnancy has an impact on a woman’s BMR. Women will have a higher BMR during their pregnancy. If someone is trying to lose weight and restricts their calorie intake too much, their BMR will decline. This is the body’s safety mechanism to prevent starvation.

Question 15

BMR accounts for approximately ___________ of energy output

Answer 15

60-70%

Question 16

How much does our BMR decline as we age?

Answer 16

1-2 % per decade

If no change in diet or activity level occurs from one decade to the next, a slow weight gain will be the result. This is why people in their 40’s and 50’s may indicate that they have gained weight and it is very difficult to lose.

Question 17

Physical activty accounts for _____________ of our energy expenditure.

What factors can affect this?

Answer 17

15-40%

a number of factors, such as body size, fitness level and the actual activity, determine how many calories are expended. Low physical activity, being a couch potato, leads to weight gain.

Question 18

Modern life is a battle against the whims and temptations of being couch potatoes.

True or false.

Answer 18

True.

In our society, modern conveniences do much of the work for us. As a result we live a much more sedentary lifestyle and must choose to be active.

Question 19

What is the thermic effect of food and approximately what percentage of calories are expended from this?

Answer 19

This is the energy used for digestion and absorption of food, which accounts for approximately 10% of the calories expended.

Larger meals and meals higher in protein result in a higher TEF

Question 20

What is thermogenesis?

Answer 20

The ability to regulate body temperature and activities such as fidgeting, maintaining body posture and shivering.

The amount of energy burned through thermogenesis is very small.

Question 21

What is necessary to maintain a healthy weight?

Answer 21

Understanding how many calories your body requires on a daily basis

Question 22

What is direct calorimetry and indirect calorimetry ?

Answer 22

Both are ways to measure the amount of energy your body needs…

Direct calorimetry measures the amount of heat that is given off by the body through the use of an insulated chamber but this method is expensive and complex.

Indirect calorimetry uses oxygen intake and carbon dioxide output and formulas to measure energy expended- this method is more accessible.

The formulas used are referred to as Estimated Energy Requirements.

These formulas are based on gender, age, height and weight and physical activity. The calories used for basal metabolism are part of the equation.

Question 23

What are the Estimated Energy Expenditure formulas for males and females?

What does it tell us?

Answer 23

Below are the formulas used for males and females, as well as the physical activity estimates as published through the Food and Nutrition Board.

Males: EER = 662 - (9.53 x AGE) + PA x (15.91 x WT + 539.6 x HT)

Females: EER = 354 - (6.91 x AGE) + PA x (9.36 x WT + 726 x HT)

Where:
EER = Estimated Energy Expenditure
AGE = age in years
PA = Physical activity estimates in chart below
WT = weight in kilograms
HT = height in meters

1 kg = 2.2 lbsR

1 m = 39.37 inches

The formula tells us the estimated number of calories required per 24 hours to maintain a current weight.

Activity Level

Sedentary - No exercise

PA Men 1.00

PA Women 1.00

Low Activity - exercises the equivalent of walking 2 miles per day at 3-4 mph

PA Men 1.11

PA Women 1.12

Active - exercises the equivalent of walking 7 miles per day

PA Men 1.25

PA Women 1.27

Very Active - exercises the equivalent of walking 17 miles per day

PA Men 1.48

PA Women 1.45

Question 24

The body mass index (BMI) is a tool used as an indicator of ……

Answer 24

a healthy weight

BMI= weight (in kilograms) divided by height squared (in meters)

BMI can be used as a measure of healthy weight, overweight or obesity in the general population. However, in certain populations such as children, teens, pregnant women, breast feeding women, short statute adults, very muscular individuals and the elderly the Adult BMI is not accurate. There are separate BMI tables for children and pregnant women.

Question 25

What is this?

Answer 25

A BMI table to determine an individuals healthy weight for height.

Using the formula a BMI < 18.5 would be considered underweight, and a BMI >30 would be considered obese

Question 26

What are some limitations of BMI ?

Answer 26

It does not take into account the amount of muscle vs. fat in the body.

This is why very muscular individuals must use caution when using the BMI tables. A diagnosis of overweight or obese must look at percentage of fat in the body, distribution of fat and health problems associated with excess body fat.

Question 27

What are the desirable percentages of body fat in both males and females?

Answer 27

Males should have between 8% to 24% body fat and females between 21% to 35% body fat. Females require higher levels of fat for reproduction. Levels greater than 24% for males and 35% for females are considered an indicator of obesity.

Question 28

What are some methods to determine a person’s body fat content?

Answer 28

The most accesible and practical method to determine body fat composition is through anthropometrics- Skin fold measures using a caliper can be done quickly and fairly accurately if the person doing the measurements is trained properly. By measuring the fat layer just under the skin at several locations, the percent body fat can be calculated.

Underwater weighing is another method whereby the difference between underwater weight and scale weight is used to estimate total body volume and the percentage of lean muscle and body fat can be calculated.

Bioelectrial impedance is a second method to determine body fat. This is based on the principle that water conducts electricity and fat resists electricity. Muscle is primarily composed of water. An instrument with electrodes is connected to the body and a painless low energy electric current is sent through the body. This concept is based on the knowledge that the more resistance that occurs, the higher the body fat percentage.

DEXA dual energy X-ray absorptiometry is the most accurate measure of body fat composition as well as bone mass. An instrument that emits small doses of radiation determines the amount of fat, lean tissue and bone in an individual. However it is very expensive and rarely used.

Question 29

While the amount of body fat we have is important, so is ____________

Answer 29

the location. Fat can be stored in the upper or lower body.

Where it is located can have an impact on your health

Question 30

What is upper body obesity- what is another name for it ?

Answer 30

Also called android obesity……..

Upper body obesity is the type of obesity in which fat is stored in the abdominal area, commonly referred to as an apple shape. This type of obesity is common in males and is linked to high blood testosterone levels. In middle age males you typically see the pot belly, but thin thighs and a small buttock. Alcohol consumption, smoking and a diet with a high glycemic load also contribute to this form of obesity.

Question 31

What is gynoid obesity?

Answer 31

A fat storage pattern typically seen in women, and also known as the pear shape…….. A pear shaped individual exhibits a small waist with much of the fat deposited in the hips and thighs.

Question 32

What along with body shape can be used as a measurement indicator of obesity?

What are the indicator measurements in males and females?

Answer 32

waist circumference and the waist to hip ratio

In males, a waist circumference greater than 40 inches and in females greater than 35 inches results in a diagnosis of obesity.

Waist to hip ratio: measure one’s waist around the belly button while relaxed. Then measure your hips around the largest part of the buttocks. Divide the waist by the hip measurement.

Diagnosis of Obesity

Waist Circumference Waist to Hip Ratio

• Females> 35 inches* 0.8 and greater
• Males> 40 inches* 0.9 and greater

Question 33

Discuss the health risks associated with the location of excess fat composition ?

Answer 33

Location of the fat is directly linked to health risks.

In males the fat in the abdominal tissues interferes with the liver’s ability to use insulin. The fat cells also lead to insulin resistance, and produce substances that increase blood clotting, blood vessel constriction and inflammation. The result, increased risk for hypertension, cardiovascular disease and type 2 diabetes.

In females, the fat around the hips and thighs is less likely to cause health issues, but is very difficult to shed.

After menopause, the shift in hormones results in an increased risk of upper body obesity. A women’s risk for cardiovascular disease, hypertension and diabetes increases with this change.

Question 34

Why does it seem that some people can eat constantly and remain thin, while others seem to just look at food and gain weight?

Answer 34

It is important to recognize that both nature and nurture play a part in determining our body shape

Question 35

Nature when it comes to body shape

Answer 35

Our genetics influences our body shape.

Studies have been done on identical twins that were separated at birth. Years later they exhibited similar body types in relation to weight and fat distribution. The genes they inherited seemed to be the determining factor vs. the environment they were raised in. Genes account for 70% of an individual’s body weight, and we inherit specific body types. If a child has normal weight parents, that child has a 10% chance of being obese. If one parent is obese the percentage increases to 40% and if both parents are obese it jumps to 80%. In addition to our genes, we may also inherit a frugal metabolism. This means you are likely to use fewer calories to maintain body function and are able to store fat easily.

When food was scarce, this was desirable but in today’s society it can be detrimental. Someone with a thrifty metabolism is prone to weight gain. Usually they also have a very low basal metabolic rate that encourages storage of fat.

Question 36

What is the set point theory?

Answer 36

A theory to support the role of genetics in weightt maintenance.

There is evidence that each of us has a genetically predetermined body weight and that the body will resist change. This set weight is a weight that was not difficult to maintain on your part. Studies have been conducted where a test subject is fed large quantities of calories while in a controlled environment. The result of course is weight gain. After the calories are decreased to appropriate amounts for the individual, the subject’s weight will return to his set point. However it does appear that it is easier to gain weight than to lose weight and the set point may change as we age. This process is not well understood but is related to various hormones and enzymes. One hormone in particular is leptin and studies are being conducted to determine its exact role in weight regulation.

Question 37

What does fat cell development have to do with our weight?

What are some other factors that affect our body composition?

Answer 37

Once a fat cell is formed, it will always be there and our bodies are predisposed to want to fill the fat cells. It is possible to shrink their size but not to get rid of the cells through dieting.

Sex, age, race and ethnicity also play key roles in our body composition.

Question 38

When it comes to nurture, what influence does it have in our desire to control weight?

Answer 38

There are many activities which affect our ability to shed calories and use energy.

In addition to inactivity, due to the modern ease of certain daily activities, there are many other environmental factors that affect our weight. These include socioeconomic status, friends and family, cultural and ethnic influences, availability of high fat foods, excessive TV viewing, lack of sleep, emotional eating, stress, fast food and smoking cessation. In other words our lifestyle in terms of physical activity and physiological factors has an impact on our body size and fat composition.