Energy Balance and Weight Management Flashcards
Energy Balance
when the energy consumed in the form of food and beverages equals the energy expended you are in energy balance and your weight is stable
Positive Energy Balance
If more energy are taken in (in the form of calories) then expended you will be in positive energy balance and gain weight
Negative Energy Balance
if more energy is expended then consumed (in the form of calories) then you will be in negative energy balance and lose weight
Energy in
calories consumed
Energy in comes from the calories you consume comes from the food you take in, the carbohydrates, proteins, and fat
Energy Out
calories expended
can be broken into three categories; basal metabolism, level of physical activity, thermic effect of feeding
Basal Metabolism
defined as the minimum amount of energy expended in order to keep a resting but awake body alive, it accounts for 60-70% or 2/3 of the energy a person expends daily, it can vary from person to person or within a person
Basal Metabolic Rate (BMR)
the rate at which body expends energy for maintenance activity (breathing, making red blood cells)
Physical Activity (relating to energy expenditure)
accounts for 25-40% of energy needs, most variable and changeable component of energy expenditure, and therefore its impact on weight gain and weight loss can be significant
during PA muscles need extra energy to move (depends on) muscle mass, body weight, activity, duration, frequency and intensity can also vary the amount of of energy you expend during PA
Thermic Effect of food
accounts for 10%
the amount of energy it takes for your body to digest and absorb the food you eat
for most purposes it is ignored its contribution to the total output is smaller than the error involved in estimating intake and output
List Several Factors that can affect BMR
Age Gender Growth Tall=greater surface area Lean Muscle mass Environment Fasting/Starving Hormones Caffeine Smoking Sleep
BMI
body mass index, the preferred weight for height standard
weight in kg over height in meters squared
less than 18.5 underweight
18.5-24.9 normal
25-29.9 overweight
30+ obese
40+ severely obese
What are limitations of the BMI measurement
BMI does not account for body composition
Athletes who are very muscular with little body fat may be categorized as overweight
BMI is not an appropriate measure for people under 5ft tall, children, adolescents, pregnant women or frail or elderly
What are the common methods to assess body composition
- Fatfold calipers: can give a rough estimate of body fat at several different locations on the body, can indicate approximate body fat % but it is rather inaccurate and takes multiple measurements and then take the average, least expensive
- Hydrodensitometry (underwater weighing): put them on a scale and dunk in a tank of water, fat floats so you are measuring lean mass. Out of tank weight-in tank weight=fat
- Air Displacement plethysmography (bodpod)
- Body Electrical Impedence : fat is more resistant to electrical current, lean tissue has electrolyte contain fluid
- Dual Energy x-ray absorptiometry (DEXA): 2 low dose x-rays can differentiate between dat, muscle, and bone, most expensive gold standard
What are the ideal body fat percentages for men and women
men 8-24%
women 21-35%
Explain the associated health risks of too much body fat
The location of fat also plays a role
• Fat distributed around the waist is called intra-abdominal fat or visceral fat
• Higher risk for CVD, type II diabetes, HTN and some cancers
• Waist circumference of > 40 in men or >35 in women is associated with developing these adverse effects
• Android obesity (upper body fat) fat distributed around the belly
• Gynecoid (lower-body obesity) fat distributed around the hips is more likely in women and somewhat protective against these negative effects
