Obesity and Weight Management

What is the definition of obesity based on BMI?

>30 kg/m2

What is the phrasing definition of obesity?

Disease defined by excess adipose tissue with associated adverse impacts to quality of life or physical health

List the BMI classifications

Obese >30

Overweight 25-29.9

Normal 18.5-24.9

Underweight <18.5

What percent of US adults are overweight or obese by BMI?

74% 

What percent of US adults are obese by BMI?

40%

What are environmental/soceital impacts seen due to obesity?

Millions are obese and overweight

Billions in annual estimated cost

Traditionally marginalized groups are disproportionately affected

What are complex interactions that can lead to excess body fat?

Genetic

Environmental

Metabolic

Physiologic

Behavioral

Social

Racial influences

What modern lifestyle change in society has led to increased excess body fat?

More eating and less exercising

What percentage of adults meet aerobic activity guidelines?

50%

What are the risks of excess body fat in children?

Children with obesity 55% more likely to be adults with obesity

Overweight children have higher risk of preventable illness as adults regardless of final adult BW

What are general health risks of excess body fat?

2nd leading cause of preventable death

Increased risk of preventable illness

Increased risk of mental decline and cognitive impairment

Decreased insulin sensitivity and adversely impacted blood lipid profile

Is a low BMI better than a high BMI in regards to mortality?

Not equal in risk but both decreased and increased BMI causes increase risk

What are the primary causes of excess body fat?

Manifestation of genetic and environmental/societal factors

Complex disorder of appetite regulation and energy metabolism

What are environmental/societal factors related to causes of excess BF?

Portion size

Access to food

Rec environment

Heredity and culture

Transportation

Socioecomomic status

What is hunger?

Physiological response to nutritional need

What is appetite?

Psychological response to nutritional need

What percentage of obesity risk can be attributed to genetic factors?

40-70%

How much more likely are children with obese parents to become obese themselves?

2x

Does genetic make-up directly cause obesity?

May not directly cause it, but can lower the threshold for its development

What are genetic influences that can affect BF accumulation?

Food intake - variation in appetite or cognitive restraint

Adipocyte formation - store/access fat more easily

Exercise activity - preference for more activity

Thermogenesis - varied metabolism based on caloric intake

In an obesity producing environment what can lead to weight gain in a genetically susceptible individual?

Sedentary and stressful life

Ready to access inexpensive food

Large portion, high calorie, good tasting food

What is leptin and what releases it?

Hormone that blunts appetite promoting satiety released by adipose tissue

Where does leptin act on?

Hypothalamus

Individuals with more adipose have (increased/decreased) leptin?

Increased

What is leptin well correlated with?

High glucose levels

HTN

High cholesterol

What is leptin resistance?

Decreased sensitivity to leptin

What can occur if there is a defective leptin gene?

Faulty production of leptin leading to too little causing lack of satiety or fullness

What is the UCP2 gene?

Regulated mitochondrial metabolite transport

What is futile metabolism?

Burning of extra calories to increase heat

What can occur if the UPC2 gene is defective?

Decreased futile metabolism causing increase in storage of calories

What is the set point theory?

Theory that people have a predetermined weight

What is the settling point theory?

Theory that there is no set point of weight instead metabolism changes until equilibrium is met

What is the evidence for the set point theory?

Large amount of people who lost weight gain it back

Diet/weight loss causes decrease in resting metabolism

Lipoprotein lipase stimulates fat synthesis in those with increased body fat who lose weight

What are criticsms of the set point theory?

Some people who lose weight maintain it

Western diet can overcome equilibrium process

Changes may be transient or temporary

PA may reverse effects

Define an obesogenic environment

Components of a persons physical, political, and sociocultural circumstances that contribute to their obesity

What are factors that contribute to an obesogenic environment?

Disparities of education, income, and stress

Attitudes toward weight

Food access and intake

Differences in TEE

Weight stigma

How does the environmental factor of portion size impact body fat?

Portion sizes have continued to increase 

How does the environmental factor of promotion of inactivity effect body fat?

Easy to be inactive in modern times

Weight gain parallels reduced PA opposed to increased caloric intake

Chronic energy imbalance

What is chronic energy imbalance?

Small progressive changes in BW

What is typically seen in regards to weight and calories due to chronic energy imbalances?

2-3 lbs gained per year

Excess of 20-30 cals per day

What are the impacts of weight stigma on BF?

Can trigger obesogenic process

Increased risk of mortality by 60% if experienced

What are aspects of the obesogenic process?

Stress hormones, physiological and behavioral changes linked to poor metabolic health causing increased weight gain

Increased eating, self control, increased likelihood of mood disorders, and avoidance of exercise

What can be done to combat the effects of weight stigma?

Stop blame and shame, treat obesity as a disease not personal failing

Improve health rather than weight loss

What are the types of healthcare biases in regard to weight?

Implicit - unaware of bias

Explicit - aware of bias

How does weight bias impact healthcare?

Adversely impacts care and its utilization causing poorer health outcomes

What type of language should be used in regard to weight?

Patient centered

Empathetic

Ask permission

What is the role of cardiorespiratory fitness in weight management?

At any weight low CR fitness causes increased risk compared to high fitness person

Increased all-cause and CV disease mortality

Obese individuals who engage in >150 mins/week of moderate intensity exercise…

Lower death rate by ½ and CVD compared to unfit normal weight counterparts

Can be fit but fat

Is weight an adequate indicator of health?

Isolated weight is not an adequate indicator

When encouraging weight loss what can be beneficial?

Focus on adopting a healthy lifestyle as opposed to a target weight goal

Dietary component of intuitive eating using ¾ full rule and external cures

Recommend activities that support all people, abilities, and interests to engage in enjoyable movement

What are examples of indirect measurements of body fat distribution?

BMI

Height/weight

Waist or neck circumference

What are some disadvantages of indirect body fat distribution measures?

May misclassify in individuals with large muscle mass or normal weight obesity

What is body composition?

Ideal way to calculate or estimate BF percentage

What is the body composed of?

Water

Protein

Mineral

Body fat

Where in the body is fat deposited?

Subcutaneously

Inter/intramuscular

Abdominal/thoracic region (visceral)

Where is essential fat needed?

Nervous system

Bone marrow

Muscles

Why is fat stored

Organ padding

Insulation

Energy source

What is fat mostly stored as?

White adipocytes

What is the minimum necessary amount of fat needed for function?

Males 3%

Females 12%

What is the common fat distribution in females?

Gynoid/pear

What is the common fat distribution in males?

Android/apple

Why does android fat distribution cause more adverse effects compared to gynoid?

Abdominal fat is visceral and more metabolically active

Increases risk of CVD and metabolic syndrome

What are important measures of fat distribution to determine health risk?

Waist circumference

Waist to hip ratio

Patterning of fat alters health risk (dependently/independently) of total body fat

Independently

What the preferred method to determine body composition?

Measure percent BF

What is the average BF percentage in males?

16%

What is the average BF % in females?

26%

What is percent BF is considered obese?

5-10% greater than normal

How do you calculate percent BF?

Weight - [weight x (measured %BF/100)] / (100 - desired %BF)/100

What is the clinically significant threshold for weight loss?

~3%

What causes changes in body weight?

Energy balance

In order to lose weight energy intake must be (less/greater than) expended energy per day

Less than

What are the effects of a positive energy balance in the body?

Positive balance created by consumed food causes increased storage of energy in the body leading to weight gain

What are components of total energy expenditure (TEE)?

Basal metabolic rate/resting energy expenditure (BMR/REE)

Physical activity/exercise energy expenditure (PA/EE)

Thermal effect of food (TEF)

What is the order of contribution to TEE of each component?

REE>PA/EEE>TEF

How to calculate TEE?

Calculate…

1. BMR/REE

2. PA/EE

3. TEF

4. Sum 3 values

What is 1 MET equivalent to?

3.5 mL O₂/kg/min

What is the typical value of RMR?

1 kcal/kg/hr

What are ways to achieve a negative energy balance?

Reduce energy intake

Increase energy expenditure

Reduce energy intake and increase energy expenditure

What is the common weight loss goal?

1-2 lbs per week

What is the average deficit for a negative energy balance?

1 lb of fat = 3500 kcal

1-2 lbs of fat loss/week equivalent to 3500-7000 kcal deficit/week

What deficit is better for adherence of negative energy balance and preserve lean body mass?

500-1000 kcal deficit/day

What are inappropriate or unsound weight loss methods?

Restricting or promoting a specific food

Various water loss methods

OTC pills and solutions

What is important to consider when reducing energy intake?

Appropriate or tolerable deficit of caloric intake

Proper balance of energy sources both macro and micro

Individualized intake values and percentages

What are broad approaches to reduction/restriction of calories?

Dietary

Time

Calories

What is a low carb diet?

CHO restriction that ignores total calories and cholesterol/saturated fat content

50-100g of CHO per day, keto <30g

What are the effects of very low carb diets?

Increase fatty acid ketones and lower appetite

Initial weight loss mostly water causing extra solute load on kidneys

What causes the formation of fatty acid ketones?

Byproduct of incomplete fat breakdown due to inadequate CHO breakdown

What are the effects of a high CHO diet?

Raise blood glucose

Trigger insulin release

Promote fat storage and inhibits fat release

Ratio: 30-30-40 (pro-fat-cho)

What are potential negatives of low CHO diets?

Raises serum uric acid causing kidney stress and stone development, and risk for those with kidney disease

Altered electrolyte concentrations causing arrhythmias

Depletes glycogen reserves causing fatigue

Decreases Ca balance causing risk of bone loss

Dehydration

Impair fetal development

Elevate cholesterol

Low in fiber

What is the relationship of water and weight loss?

Majority early weight loss is water

Same amount of fat is lost regardless of hydration/fluid intake

Longer term deficit promotes fat loss (increase in fat loss compared to start)

What is a low fat diet?

Known as a mediterranean or ornish diet

Fats/cholesterols are replaced with whole grains, legumes, fruit, and veggies

Ratio: 70-20-10 (Pro-cho-fat)

What are disadvantages to a low fat diet?

Many low fat foods are highly processed or high in sugar/additives

Too low in fat can interfere with vitamin absorption and limit intake of essential fatty acids

What is a high protein diet?

Known as paleo

Emphasis on fish, lean meats, fruits, and non starchy veggies

Naturally low in fat

Increases satiety and TEF due to protein digestion

What is the disadvantage of high protein diets?

Hard to adhere to

What are potential problems of a high protein diet?

Strain on liver and kidney function accompanying dehydration

Electrolyte imbalance

Glycogen depletion

Lean tissue loss

What is a semi-starvation/very low calorie diet?

Used in morbid or grade 2 obesity >40 and 35-39.9 with comorbidities

Last resort diet with extreme medical approaches

Monitored in a facility

Specialized powdered food rich in protein of 500-800 kcal/day

What are the advantages of a semi-starvation/very low calorie diet?

Breaks habits

Promotes rapid weight loss of 3-5 lbs per week

Report of satiety because of mild ketotic state

What are disadvantages of semi-starvation/very low calorie diets?

Bad breath from ketones

Cardiac arrhythmic death

Dehydration and gallstones

Difficult to maintain weight loss

What are types of intermittent fasting?

Time restriction

Alternate day fasting of a fast day and feast day

5:2 ratio of 2 fast days 5 feast days