Flashcards in Exercise And Appetite Deck (54):
Is exercise an effective weight loss strategy?
Most people think so
Do people get discouraged from exercising, why
Yes because its hard to lose weight with exercise
What’s the formula for weight maintainence?
Balance between energy intake and expenditure
Does exercise lead to weight loss - diet only vs exercise only intervention in 52 men with obesity - 700 intake vs expenditure
Improved body weight with both - you lose a bit more of total fat with exercise
Does exercise lead to weight loss - 201 obese women in 4 gps - vig int/high duration, mod int/mod duration, mod int/high duration, vig intensity/mod duration - 1200-1500 kcal 2 yr follow up - 2 findings
No significant in weight loss between gps
Retrospective grouping of PA greater than 275 min/wk with diet was associated with weight loss maintenance of >10%
Does exercise lead to weight loss - age 18-55 278 adults in gps of self-help, mod PA (150 min/wk), high PA (300min/wk) for 18 months. - 2 findings
0.7% reduction of weight in self help, 0.9 with mod PA, and 1.2 with high PA
PA greater than 225 min/wk associated with greater weight gain ~1.5kg over 18 months
Does exercise lead to weight loss - 202 men and women (45-75 yrs) randomized to control vs 60 min of mod-vig aerobic PA/day 6x/wk for 12m. 2 Finding
1.6kg weight loss and total fat mass loss
Does increased PA lead to weight loss - 10 year prospective study with 4944 men and women, PA, body weight and waist circumference assessed at 0, 5, 10 years - findings?
PA increase from year 0-5, circumference gain was 0.56 cm lower and body weight gain was 0.59kg lower than people who did not increase PA by year 10 - thus they want health programs to promote PA
Does increased PA led to weight loss - prospective study over 85, 96 and 2007 - 2 findings
activity above the recommendations was associated with 1.8kg less weight gain over 11 years in women and 2,1 less in men
increased PA slows weight gain
Does increased PA lead to weight loss - prospective 20 year longitudinal study to see the association between habitual PA and BMI - 3554 men and women aged 18-30 - 3 findings
increased PA slows weight gian
men with high PA gained 2.6 kg less
women with high PA gained 6.1kg less
PA and weight in kids - School based PA inerventions
No beneficial effects on BMI
PA and weight in kids - longitudinal study of 212 kids from 5-8 to assess PA (accelerometer), BMI, and metabolic status (IR (insulin resistance), TAG, HDL, BP)
No impact on BMI, but improvements in metabolic health
Effects of PA on appetite/changes in gut hormones following exercise - 1
- relative to dietary energy restriction, exercise leads to acute increases in PYY and GLP-1 and reductions in ghrelin - associated with reduced subject appetite ratings
Why don't we see the results of exercise - 3
it decreases metabolism and increases appetite
- we reward ourselves after going to the gym
7 potential mechanisms of altered gut hormone secretion
increased SNS activity
altered gastrointestinal motility
cytokine release - reacts with receptors same with FFA
changes in plasma glucose and insulin
considerations of gut hormone alteration from exercise (3)
acute vs chronic effects
low vs high intensity activity
compensators and non compensators of PA
compensators increase energy intake after exercise and show a preference fro high fat, and sweet foods
How are responses to exercise individualized?
Genetic factors - FTO gene - involved in the regulation of ghrelin, fat mass and obesity associated - first identified by Frayling et al in 2007
drugs that block the entry of sugar to the kidney - 90g/day
for every 1kg lost, 100kcal was added to their appetite
PA and appetite - 34 obese men with a 12 week exercise intervention - 500kcal expenditure 5 days a week - 2 findings
20 responders lost weight and 14 non responders
non responders had increased hedonic liking and wanting for high fat, sweetened foods after exercise
How is exercise more about calories in than calories out? (3)
reduced stress, anxiety and depression
improved mental health
Why do food manufacturers want it to be about the PA
so they can sell their products - just increase your PA to burn the energy!
What does it mean to health wash a brand - 6 brands that do it
associate themselves with PA - Coke, Red Bull, milk, McDicks, Subway, Tim's
TEE and PA level in developing vs developed countries? (what did they use)
No differences (doubly labelled water)
Is it feet or food that leads to overweight?
Sedentary does not lead to obesity but obesity leads to sedentary - reverse causation
Doubly labeled water to measure TEE in a group of Hazda adults over 11 days - 3 findings
They have greater PA
no diff in TE
supports idea of constrained energy expenditure model - you plateau your energy expenditure level
Giving mice more exposure of a running wheel
no difference in energy expenditure
WIll PA reduce weight?
not necessarily but it is important for improving metabolic health
Is calories in or out more important for weight management?
in - lose weight in your kitchen, not your gym
PA is promoted as - 3
health enhancing behaviour capable of reducing risk of major diseases such as heart disease, stroke, T2D, breask and colon cancer, premature all cause mortality
maintenance of healthy body composition
prevention and management of overweight and obesity
Why dont they think that PA can reduce weight? - 3
"Why exercise wont make you thin" - Times
"does running make you fat" - The Guardian
"could exercise be making you fat" the telegraph - they think it stimulates appetite and promote overconsumption of food
view of authors that dont think exercise can fix everything
Overweight and obesity are caused by excess energy intake rather than insufficient energy expenditure = efforts to counter obesity pandemic through PA is useless
low levels of PA/sedentary is associated with
risk of overweight and obesity but no cause and effect
Can people with high levels of PA still gain weight
yes but to a lesser extent
well-controlled intervention demonstrates that
increased PA alone/with diet can lead to substantial weight loss
meta analysis of randomised, controlled trials conclude that exercise generally results in
modest <5 kg weight loss
Studies wanting to answer whether PA increases appetite and food intake often take one of two perspectives
single bouts (acute response) vs over weeks/months (chronic response)
short term response of appetite, appetite hormone and energy intake response to acute bouts of exercise
not a strong relationship between energy expenditure and intake
when does compensatory changes in appetite perception, appetite hormones (ghrelin and peptide YY) and food intake happen?
in response to dietary induced energy deficits but not exercise induce energy deficits - energy induced actually promotes satiety
why is is hard to see if PA/exercise increases energy intake in the long term
difficult of objectively measuring energy intake in free-living conditions
Energy compensation approaching 84% of energy expended according to a systematic review -
long term (about 80 weeks) but few studies were conducted over this length of time and they couldnt establish whether the compensation was due to increased energy intake, decreased energy expenditure or a combo of both
evidence relating to compensatory changes in hormones and appetite perceptions after periods of exercise training
Is TEE stable?
relatively - regulated homeostatically
does total daily energy expenditure increase in proportion to PA in an additive way?
No, its constrained within a narrow range and metabolic activity is reduced when PA is increased - evolutionary advantage favouring survival - constrained total energy expenditure.
FTO risk variant
increased energy intake and obesity
Why is there some truth in "you cannot outrun a bad diet"
easy to compensate for the calories expended in exercise without dietary vigilance
Best way to lose weight
dietary restraint and high levels of PA
Who published a letter to the editor?
British Journal of Nutrition from the authors in 2011
can individuals experience substantial weight loss with regular PA?
Yes - no relationship between amt of energy expended and changes in body weight
What can PA do for sure on ingestive behaviour
subtantial postitive impact if their overeating is primarity driven by stress, depression, poor self esteem/unrestorative sleep
How can PA affect the homeostatic and hedonic system
homeostatic may respond with a compensatory increase in hunger but hedonic can lead to a substantial decrease in energy intake
Regular PA and stress-induced weight gain
stress relief activities such as relaxation, yoga and meditation
dont burn a large amont of energy but effective in reducing emotional eating episodes and reducing body weight