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
Explain the associated health risks for too little body fat
- Unable to preserve lean tissues during wasting disease, medical stresses
- Menstrual irregularities, infertility in women
- More likely to give birth to low birth weight baby
- Increases risk for osteoporosis
Discuss the prevalence of overweight and obesity among American adults
2/3 of adults are overweight or obese
How do fat cells develop and what is the role of LPL in fat storage
Hyperplasia • Increase in number of fat cells Hypertrophy • Increase in cell volume If you lose weight you do not lose fat cells just decrease the size of the ones you have Fat cell metabolism • Lipoprotein lipase • Promotes TG storage in adipocytes • More fat cells =more LPL activity • As fat cells shrink, LPL remains • Loss of body fat signals gene to increase LPL
Discuss how the regulation of hunger and satiety contributes to the development of overweight and obesity
There is a disconnect between the signals that cue us to eat and those that tell us when to stop
Hunger and appetite drive us to eat
• Hunger physiological need
• Appetite psychological desire
Satiety
• Satiation is the feeling of fullness that stops us from eating more and determines how much we eat at once
• Satiety: the perception of fullness that lingers after a meal and determines the length of time in between meals
Physiological factors that influence our eating behaviors include Hormones neurotransmitters neuropeptides
Research to determine how these factors can be manipulated to influence our eating behaviors
• Obesity is complex targeting any one single hormone is not likely to work for everyone
Discuss how genetics contributes to the development of overweight and obesity
Identical twins raised apart have similar weight gain patterns
While fraternal twins vary less in weight than two unrelated people
In studies comparing parents with their offspring
• Child with no obese parents has a 10% risk of becoming obese themselves
• Child with one obese parent has a 40% risk
• Child with two obese parents have an 80% risk
Genetics accounts for about 40% of weight difference
Genetics influences where fat is distributed, effect metabolic rate, fuel use and brain chemistry
Discuss how the environment contributes to the development of overweight and obesity
External Cues & Food availability
• Availability of inexpensive high calorie foods in large portion sizes can lead to overeating when consumed on a regular basis
Physical Inactivity
• Combined with sedentary lifestyle and inactivity leads to positive weight balance and weight gain overtime
Fad Diets
All fad diets will help you lose weight if you take in fewer calories than you expend, but fad diets are not sustainable in the long term and may not be nutritionally sound
offer exaggerated claims
Side effects include headache nausea or even death
Describe the dangers of weight cycling
“yo-yo” dieting
gain regain of 10% of body weight can cause physical damage
fluctuations associated with increase risk of chronic disease and early death independent of overweight
Describe drug therapy used to treat obesity
Candidates for drug therapy BMI >30, or >27 with comorbidities
Appetite suppressants, enzyme or hormone blockers, herbal preparation
some require prescriptions others do not none are without side effects
• Amphetamine like stimulants affect CNS
• Sibutramine works on NT, reduces hunger
• Orlistat, lipase inhibitor
None work without behavior change, reduced energy intake and increased physical activity
Describe surgery used to treat obesity
Gastric bypass
• BMI > 40, or >36 with comorbidites
• Stomach is drastically reduced in size
• 1L to 30mL
• Reconnects the lower part of SI with new stomach essentially bypassing the upper part of the SI where most of nutrients are absorbed
• Can lead to nutrient deficiencies so need to take supplements
Also stomach stapling and jaw wiring
Characteristics of sound weight loss program
- Should not recommend less than 1200 calories a day
- Should not promote a rapid loss of weight
- Should not include special foods that are not readily available
- Should include foods that you could reasonable choose off a restaurant men
- Should not cause negative health effects
- Changes eating problems/habits
- Improves overall health
- Consult a doctor prior to starting a weight loss program
characteristics of sound eating plan
- Diet planning principles
- Nutritional adequacy
- Well balanced diet that emphasizes fruits vegetables whole grain lean meats or meat alternatives and low fat dairy products should provide enough nutrients to maintain health
- Moderation small portions consume less calories
- Complex carbs, fresh fruits, vegetables, legumes, whole grain
- Drink water
- Helps GI tract adjust to a high fiber diet
- Choose fat sensibly
- Don’t eat to many low fat and fat free products
- Don’t eat foods high in saturated fat
- Watch for empty calories
- Alcohol
- Candy cookies pastries etc.
