Exercis e Genetics Activity 4: Metabolism Brown fat cells are more adept at metabolizing stored fat – TRUE Exercise can convert white fat cells into brown fat cells – TRUE Low basal metabolic rate in kids cannot be used to predict obesity later in life- FALSE Basal Metabolic Rate increases with body weight - TRUE
The basal metabolic rate can be used to predict what happens later on in life. The lower the basal metabolic rate early on, the greater the chance of obesity because the low basal metabolic rate generally means a very efficient body- but in this case, that’s what you want. You don’t want real efficiency. You want to be using up a lot of energy to run your metabolic processes. The basal metabolic rate increases as weight is gained – because it becomes harder to run everything in the body. & by the time weight is put on, that basal metabolic rate is very similar in the obese and the non-obese. What this suggests: people who are born with a low basal metabolic rate are somehow preprogrammed to have to put on weight so that they can match the basal metabolic rate that is found in people who naturally tend to be lean. Setpoint theory : the body having in mind (not consciously) the weight that it is happy with – and the basal metabolic rate will increase until it matches this setpoint. In order to do this, people with low metabolic rate will have to put on weight. A way to fight this : Reducing calorie intake ▫ But the body resists this [resistance to cutting back on calories]. It does not like to be famished of calories ▫ In short term, this will work. [if you don’t eat, weight will be lost] ▫ Consequences? By reducing caloric intake – the body begins to readjust by reducing the BMR ▫ Why? Because there are fewer calories coming in – we don’t have as many calories available to run everything that needs to be run, so we better reduce the amount of energy needed to do all those things – hit a plateau ▫ Weight loss → BMR reduced = hit the plateau How do you counter this? Exercise! ▫ Increases BMR [even when you’re not exercising] ▫ You are kind of “reprogramming” the body ▫ More exercise = More cals burned when not exercising [real value of exercise] ▫ Reduce caloric intake + Exercise = works well. Bob Adelman [photographer who took pictures of Martin Luther King] Decided he was overweight when he couldn’t fit in his car
Documented his weight loss with photography He cut back on calories + began a program of exercise [run a marathon] Within 3 months, he started to look significantly better By 9 months, he was looking pretty lean After a year, he was muscular + lean He went from 315 pounds to 195 pounds [a lot of effort, but can be done] Was he able to keep it off? Because it is easy to lose weight, but the hard part is maintaining that weight loss. [he was able to keep it off – but this is a rare example] We usually see the yo-yo effect: Weight is lost, and then put back on, usually with an interest.
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