Flashcards in Week 3 Nutrition and Obesity Lecture Deck (31)
what two factors primarily contribute to obesity?
genetics and lifestyle (diet, exercise, sleep)
what BMI range is overweight?
what BMI range is obese?
how do you calculate BMI?(2)
BMI=kg/m^2 OR BMI=(lb x 703)/in^2
a high MBI has been correlated to increased risk for which diseases?3
hypertension, cardiovascular disease, sleep apnea...
as BMI increases, standard mortality rates__
how do you determine waist to hip ratio?
WHR=waist circumference/hip circumference
what is a healthy WHR for men? women?
what is an "at risk" hip ratio?
greater than or equal to 1
what has been better correlated to incidence of myocardial infarction, BMI or WHR?
describe the adipocytes of an overweight person?
adipocytes are larger and more numerous
describe the adipocytes of a average sized person who was once overweight
adipocytes are smaller but still more numerous. in a person that loses weight, adipocyte size decreases but number stays the same
scientists have discovered how many loci involved in mendelian forms of obesity? how may loci are contributing?
9 involved, 58 contributing
does a genetic predisposition to obesity mean you will be fat?
no. lifestyle changes can overcome genetics in most cases
what is the set-point theory?
your body has a functionally optimal weight range that it tries to maintain by influencing appetite
what is satiety?
Leptin: secreted by, role2? long/short term factor
stimulates hypothalamus to reduce food intake and increase energy expenditure
leptin levels are increased/decreased with increased adipose tissue
Ghrelin: secreted by? stimulates2? long/short term factor
secreted by stomach when you anticipate a meal
stimulates hypothalamus to release hormones and increase food intake
PYY: secreted by? role3? short or long term factor?
produced in ileum and colon
suppresses appetite, lowers food intake, slows passage of nutrient through gut
orexin: produced? role? 3
produced in lateral hypothalamus
increased food consumption, wakefulness and suppresses REM
your a fat person, which hormones (PYY, orexin, leptin, ghrelin) are good for weight loss?
leptin and pyy
how is sleep related to obesity?
decreased sleep increases the risk of obesity
what effect (on hormones) does a lack of sleep have?
decreases leptin, increases ghrelin
what are the weekly physcial activity guidelines for americans?
1 hr and 15 min each week of vigourous aerobic activity, 2 hr 30 min of moderate aerobic activity, muscle strenghtening atleast 2 x a week
exercise does not burn that many calories, so why is it so effective in weight loss?
lean body mass (built by exercise) increases basal metabolic rate which burns more calories than physical activity
why do our bodies not require carbs?
glucose and glycogen can be made from gluconeogenic sources
what was the atkins diet? did it work?
low carb, high protein, high fat diet. It worked in the short-term becuase our bodies were breaking down fats to make energy, but it was not helpful in sustained weight loss and actually led to some health issues correlated with high fat intake
why is high fructose corn syrup bad?
fructose bypasses normal regulatory mechanisms of glucose and is readily converted to excess fat. fructose is also more effieciently metabolized by the liver so less escapes into blood.