PA, Exercise, and Obesity
13. For the National Weight Loss Registry participants, how many kcal per week or day were expended through PA?
2,800 per week (or 500 kcal/day)
8. Describe the study conducted by Jakicic concerning exercise and weight loss and interpret the results
201 women were told to eat a calorie restricted diet and walk on treadmill for 5 days of the week with different intensities/ duration. There were no significant weight loss or changes in cardiorespiratory fitness between assigned groups, but subjects exercising longer and at higher intensities have lost more weight. All lost weight.
3. The Centers for Disease Control (CDC) tracks PA levels in the U.S. They estimate activity and inactivity levels based on self-reported data. What percent of adults indicate that they meet the aerobic and the muscle strengthening guidelines in America? What do objective measures indicate regarding the percentage who meet the cardio guidelines?
60% said that they do meet the requirement but when using an accelerometer it showed that only 8% actually met the guidelines.
28. Recognize the benefits of regular exercise, other than energy expenditure
Appetite control (affects hormones ghrelin and insulin, short term appetite suppressor, exercise normalized our appetite- we eat more healthy when we are exercising) , preservation of FFM (strength training), positive psychological effects (less depression), decreased abdominal fat, increased insulin sensitivity, greater use of fat as fuel (referring to body fat), and increased fat oxidation.
23. Who tends to consume more kcal, exercisers or non-exercisers, given the same body weight?
Active people have higher energy intakes than sedentary individuals.
18. According to the literature reviews, how much "extra" body weight (kg) can the average person expect to lose through PA/Exercise if s/he is also consuming an energy restricted diet (compared to diet restriction only)?
Adding exercise to kcal restriction doesn't seem to help much with weight loss
5. Using doubly labeled water, what is the general relationship between PAL and BF%
BF% decreases as activity increases. There is a negative correlation. Doubly labeled water is modified with an isotope so we can track water usage.
2. Name five demographic factors that predict PA. Describe the associations
Demographic (more likely to be less active) Age (old) Income (poverty) Gender (female) Race (black or hispanic) Education (low education)
14. What can we conclude about the weight loss that tends to occur as a result of intervention studies concerning PA and exercise?
Despite the many advantages associated with physical activity, weight loss through PA is usually much lower than expected.
30. For weight loss, which is more important, diet or physical activity (exercise)? Explain
Diet- shown in results of studies above. PA doesn't reduce weight significantly
17. What can be concluded from Wing's review on PA and weight loss?
Does exercise alone produce weight loss- 6-10 trials showed some effect compared to NO treatment. They average weight loss was 1-2 kg. Effects tended to be dose-response, meaning that if you wanted to lose a lot of weight through PA you had to engage in A LOT of PA.
26. What is post exercise energy expenditure and does it play a significant role in weight management? Explain.
EPOC- amt of energy we expend after we stop exercising. Doesn't play much of a significant role in weight management. Only increases energy cost of exercise by 3-5%
25. What is the misconception regarding intensity of weight loss for weight management?
Fat burn mode is normally long and slow, but the best is long and fast. Fat burn mode is a lie. They focus on the percent fat burn and not the total number of calories. You want to burn more calories.
4. Are most school children active or inactive during the school day? Are they more active or less on weekends? Explain
Few children exercise; they play. When 11-16 yr olds were monitored they did not achieve one 10 minute bout of sustained activity during 3 school days of monitoring. They are less active over the weekends (no recess, probably playing video games)
24. How does exercise intensity (walking vs jogging) influence energy expenditure and substrate utilization?
Higher intensity is better. Long and slow is not as good as long and fast.
29. What are the limitations associated with weight loss through regular exercise?
Increased food consumption, fatigue, time restraints, injury, difficult for obese to exercise, low energy expenditure for the amount of work, may compensate for the extra work by being less active during other parts of the day
6. What are the problems with using cross-sectional research to learn about PA and body weight or obesity?
Instead of a video of someone over several days vs. a still picture. We can't decide if physical inactivity leads to an increase in body fat, or does body fat lead to decreased physical activity.
27. According to the DHHS (government), what are the official PA/Exercise guidelines for good health? How much exercise is recommended for weight loss and weight loss maintenance?
Minimum >/= 150 min per week of moderate intensity (for general health) >/= 300 min/wk: weight management, including weight loss and maintenance of weight loss The guidelines cover multiple objectives.
22. What effect does exercise have on energy intake?
Most exercisers report that exercise is followed by an acute suppression of hunger. Hunger suppression is short-lived. Suppression of hunger more likely to occur after high intensity exercise. Long duration exercise has been shown to increase energy intake after exercise. Those who eat ad libitum have less than expected weight loss.
9. With Jakicic's study, did the 4 assigned exercise groups differ statistically in the amount of weight they lost over the course of the study?
No differences in weight loss or changes in cardiorespiratory fitness between groups.
20. What can be concluded from resistance training studies regarding weight loss and fat loss and changes in FFM?
Participants (after 15 weeks) gained 1 kg more in FFM and lost 1 kg in fat mass, but weight loss was not significantly greater in the lifters. Changes were maintained 6 mo following the supervised sessions.
19. What can be concluded from Hansen's review on PA and fat loss?
Only 4/21 studies indicate that exercise + diet results in > fat loss than diet alone. (No additional loss of body fat when exercise added to diet.) Resistance DOES tend to prevent loss of FFM
32. Overall, what can be concluded regarding the effect of PA and exercise on weight loss and body composition?
PA doesn't significantly affect weight loss
1. Define physical activity, exercise, and MET
Physical activity- Body movement produced by the skeletal muscles that results in energy expenditure. Exercise- a subset of physical activity, volitional, planned, structured, repetitive physical activity aimed at improvement or maintenance of physical fitness or health. MET-(Metabolic equivalent) energy requirement of an activity expressed as a multiple of RMR (3 METs =3x RMR). Whatever your RMR is that is one met for that person.
16. What can be concluded from Miller's exhaustive review on PA and weight loss?
Restricting diet results in loss of weight, but exercising on top of that doesn't result in much of a significant difference in weight loss. Exercise with no kcal restriction only resulted in about 3 kg weight loss.
21. Overall, what do prospective studies show regarding PA and weight management?
Restricting kcal results in weight loss, but exercising on top of that only results in about 1-2 kg more weight loss. Exercise (vigorous activity) seems to help prevent weight gain more than weight loss.
12. What was unique about the women in Donnelly's study?
The women didn't lose as much weight as the men did. They exercised more, but didn't cut calories to create an energy deficit.
11. According to Donnelly, what weight loss results occur when men are given a supervised exercise routine with an ad libitum diet?
They lost weight linearly for nine months and then it plateaued.
31. Why do adults tend to lose less weight than expected when trying to lose weight through exercise?
They make up for it in kcal intake
10. With Jakicic's study, did those who exercised more lose more weight or less than their counterparts?
Those who exercised more lost more weight than their counterparts.
7. What is the difference between focusing on physical activity and focusing on physical inactivity? What is a good index of inactivity or a sedentary lifestyle?
We can be both active and inactive, like working out an hour a day and then being sedentary the rest. Screen time is one of the best indicators of inactivity or sedentary lifestyle.
15. Give 4 good reasons that help explain why adults typically don't lose much weight as a result of exercise.
increased energy intake, decreased movement between bouts , decreased energy expenditure associated with a decreasing body mass over time, inconsistency