Weight Loss - Lecture 20 Flashcards
How do you know when you’re full?
Energy surplus (15 kcal difference that causes weight gain) is matched with appetite and energy expenditure
How does the body manage energy expenditure with energy intake
Controlling appetite
Grehlin
Hunger signals from the stomach that go to the brain and tell you you’re hungry
Why do people say to eat slowly?
It takes about 20 minutes for your brain to register that the grehlin signal is turned off making you full.
Leptin
Sends signal from adipose tissue to brain to say you’re full.
Prader-Willi Syndrome (Improper Signal Regulation)
Excessive grehlin; that causes excessive hunger and food consumption
Are there medications to control appetite
No effective medications so far
Key Role of Leptin
Decrease appetite and increase metabolism
Leptin Deficiency
Unable to produce leptin signals that tell you you are full
Hyperphagia
Constantly hungry caused by a deficiency of leptin
Prevalence in Leptin Deficiency
Only a few dozen cases; not a cause for obesity
Leptin Resistance
Too much leptin; signal does not get sent to brain
Who is affected by leptin resistance more?
Obese people
When there is leptin resistance what happens to food intake?
Since the signal is not being processed by the brain, food intake will increase because we are not getting the signal that we are full.
Do lean people have leptin resistance
No because leptin is released from adipose tissue also known as your fat cells so lean people don’t have high amounts of leptin circulating
Gut Satiety Hormones (Where are they usually released)?
Released in the intestine in response to food to decrease urge to eat
What nutrient increases gut hormone production
High fibre diet
Do individuals with obesity secrete more or less appetite reducing gut hormones than lean people
Secrete less appetite gut hormones due to lack of signal
Volumetrics - Energy Density
Uses hormones produced in the intestine to help with satiety
Purpose of Volumetrics
Choose lower energy dense foods per volume of food that will help you feel full (satiated) and less hungry
What would a low and high calorie/energy dense food be?
Choosing more fruits and vegetables over meat and cheese
Purpose of Fibre Pills (PGX)
Thought that increasing the fibre would decrease Glycemic Index and therefore increase satiety
Meta Analysis Results of PGX
- No significant effects on body weight
- Big reductions of LDL due to fibre preventing it from being reabsorbed into bloodstream
How does the environment play a role in weight gain? (Bottomless soup bowl experiment)
Thinking about how much you want to eat tricks you into eating more
What was determined from free popcorn experiment
1) We’ll take the food that’s presented to us
2) If there is a lot we’ll try to each as much as you can
Advertisements and their relationship to Food Consumption
Seeing an ad on tv makes us eat unhealthy food.
How does Variety affect food consumption
The more variety of foods there are the more you want to try.
Plate size and food consumption
Size of plate tells you how much to eat. (Smaller plates mean small servings)
All the social factors that influence food intake
Portion size, Taste, Advertisement, Variety, Plate Size, Availability
How Dieting helps with obesity?
Cutting down amount of carbs you intake can help for a short period of time (weeks or months)
Why is diet not a cure for obesity
Diet will tend to rebound at a point in time and then weight gain occurs and we start back at where we were initially
Why do we tend to rebound even after dieting
Physiology; you can’t diet forever because your body likes to store energy and hold onto fat for times where food may be scarce
Does this mean dieting doesn’t work?
Not true as there is about a 3-5% long term effect that comes with health benefits.
What does the body do with calories or excess energy? (how diets basically work)
Body willingly stores energy and convert calories into usable energy (fat)
Why do meal replacements work so well with people losing weight?
No need to think about what to make to eat.
How pricey is dieting compared to normal eating?
Average cost of food in Toronto is just a bit less than a meal plan.
How is Atkins dieting not necessarily a health benefit
Although it’s high in fat and protein making you full but fibre intake is low, cholesterol becomes very high and other long term health related issues.
Effects of Fat mass on surviving during starvation
Obese person lasted a year and lost 126kg but the lean man lasted 60 days.
What did the fat mass starvation prove?
The obese man was still heavier, so if you want to diet while obese it will take quite some time to lose that weight.
Why does it take so long for one to lose high amounts of weight.
Once again it’s physiology as the body wants to store energy not lose what may be useful.
*Physical activity and obesity reduction: dose response?
The more calories you burn the more weight you lose
Following the guidelines how many weeks of exercise does it take to burn 1kg
10 weeks of constant 2000-4000 kcal/week
Why does weight loss in Diet+Exercise equal the same in just Diet?
It’s takes a lot of effort to burn a significant amount of calories and lose minimal amounts of weight
Does exercise necessarily help lose weight?
It’s more of a health benefit rather than a weight loss solution.
The Fat Burning Zone
The idea that low intensity fat burning exercises loses weight is untrue
*Why is the fat burning zone untrue
If we look at the amount of calories you burn being equal to weight loss, high intensity exercise burns more calories and therefore more fat.
Over 95% of people will not maintain a reduced weight.
Weight loss patients who have a goal of 50kg rebound.
Whose fault is that?
Gliosis and how it makes you potentially gain weight/keep weight as is
Prevents you from starving to death by resetting weight at higher and higher set points
Gliosis
Scar tissue in the hypothalamus
Who are the people who don’t have this
Those who do not have this permanent reset in their brain
How do your bones contribute in regulating weight?
Bones have feedback signals
What do the feedback signals indicate?
You’re starving because of stress on bone.
*How does the body adapt to body weight changes when it comes to Resting Energy Expenditure?
The body makes sure we don’t eat too much calories so energy expenditure goes up
Does everyone have this increase in energy expenditure from overeating?
Those who are able to control the amount of calories they gain and burn are likely to have this increased energy expenditure.
What does the body do during undereating?
The muscles will burn less calories (decreased energy expenditure) when under eating because the body is trying not to make the weight disappear.
What does it mean when someone is energy efficient?
Those who keeps their calories; typically harder to lose weight.
Why does under eating sometimes cause weight gain?
Body’s physiology refusing to lose weight.
Weight loss associations with increases in Skeletal muscle efficiency
The longer you exercise and the more you do it, the more weight you lose.
Why is physiology making it hard for people to want to lose weight?
People do a lot more exercise and expect to lose a lot more weight overtime, but body’s physiology does not allow that.
How does appetite affect those exercising in an attempt to lose weight
Longer bouts of exercise is related to having a greater appetite, so losing weight seems unrealistic when you need to eat a lot.
Body weights of those who are no longer sedentary are all the same
How sedentary workers lose weight from increased energy expenditure
*What does an increase in energy expenditure prove?
When the energy expenditure increases, there is the possibility to lose weight but the body’s physiology tries to reset because it sees this loss as negative.
How do people manage to keep their weight down for several years?
Eating far less than they need to and sometimes even less due to energy requirements changing.
Problems with constant weight gain and weight loss (Weight Cycling)
- decrease metabolic rate
- CHD risk factors
- Cancer risk factors
Three Pillars of Obesity Management
Psychological Intervention, Pharmacological Therapy, Bariatric Surgery
What do weight loss drugs try to target?
Intake or Expenditure
How do the drugs target intake
Affecting appetite and how much you eat as well as Absorption of food
How do the drugs target expenditure?
Affects Stimulants
How many weight loss medications are approved in Canada?
4 (Orlistat, Wegovy, Saxenda, and Contrave)
Orlistat
Prevents lipase from cutting triglycerides and letting them be absorbed by the intestine.
What is the weight loss expected with Orlistat?
3% above lifestyle
Side effects of Orlistat?
Loose bowel movements
- Fat turns to liquid in body temperature and comes out liquid
Why should patients on Orlistat be on a low fat diet?
Because the fat that doesn’t get absorbed ends up causing a mess in your bowels so keeping a low fat diet would decrease loose bowel.
Cost of Orlistat?
$180/ month (Not covered by OHIP)
What is Saxenda
An injectable medication that suppresses appetite
How is Saxenda helpful for those with obesity
Because obese people have less gut hormones, taking this will help with their satiety.
What’s the weight loss expected with Saxenda?
8% above lifestyle
Why do insurance companies want to see proof of weight loss to cover medication?
Because of stigmatization that the person has no will power and instead relies on medication.
Side effects of Saxenda
- Nausea
- Gallstone and acute pancreatitis rare
Cost of Saxenda
400$/month
Contrave and how it was made?
Two medications that had a side effect of weight loss were put together.
What does contrave do?
Suppresses Appetite
Expected weight loss
8.1%; 5% due to lifestyle
Semaglutide (Wegovy)
Imitates GLP-1 Hormone that regulates appetite and lower calories consumed.
Expected weight loss
15%
Cost of Wegovy?
$1627/month
Surgery and its effects on weight loss?
Surgery is the only thing keeping people at a sustained weight loss.
How does gastric surgery work?
Targets stomach size or time to absorb (shorten intestine)
Benefits of Bariatric Surgery on Cardiovascular Risk
Decreases Hypertension, Dyslipidemia, Diabetes, Sleepapnea
Is it a cure for these diseases like diabetes?
No; they just don’t need to take their medication associated with disease.
What is the reduction of risk with surgical weight loss?
89% risk reduction
Wait time for bariatric surgery in Ontario?
2-3 years
Overall difference in weight loss with diet vs. surgery
Far greater weight loss with surgery that is sustained compared to diet
Why do people not want Bariatric Surgery?
They believe in their willpower and think it’s unnecessary
Firmly held belief by society and obese people
Problem of not losing weight is because of their lack of willpower
How does bariatric surgery affect hormones causing weight loss?
Resets that gut-brain signal to a lower number rather than a higher number.
What does resetting to a lower number entail?
Appetite decreases and weight will be lost.
Percentage of people that don’t need bariatric surgery?
42%
Downside of waiting too long to get bariatric surgery?
Excess skin form after surgery and will be an impairment on QOL due to immense weight.
Health professionals tend to attribute patients health issues to excess weight
Health professionals not listening to the problem.
Obese patients get worse health outcomes because of late diagnosis
Health professionals ignoring the real issue and focusing on something irrelevant
Weight Loss products are the #1 scam because?
They tell patients a lie to make them desperate to buy it.
Main message about obesity and weight control?
Understand that there may be nothing we can do to cure it, but we need to get our biases in check before judging someone.
