Comprehensive Obesity, Nutrition, and Food Safety Key Concepts

Obesity

Excessive and unhealthy accumulation of body fat

Fat-free mass

All body components except fat (muscle, bone, organs, water)

Total body fat

The total amount of fat in the body

Subcutaneous fat

Fat under the skin used for insulation and protection

Visceral fat

Fat around organs that increases disease risk

Underwater weighing

A highly accurate method comparing body weight in water vs.

Dual-energy X-ray absorptiometry (DXA)

Imaging technique using X-rays to measure body fat accurately

Skinfold thickness

Measuring fat using calipers at body sites

Energy

The capacity to do work

Energy intake

Calories consumed from food and drink

Energy output

Calories burned through body processes and activity

Biological fuels

Carbohydrates, fats, proteins (and alcohol)

Basal metabolic rate (BMR)

Energy used for vital functions at rest

Resting metabolic rate (RMR)

Energy used at rest after eating; slightly higher than BMR

Physical activity

Energy used for movement

Thermic effect of food (TEF)

Energy used to digest food (5-10%)

Nonexercise activity thermogenesis (NEAT)

Energy used for small, non-exercise movements like fidgeting

Energy equilibrium

Intake equals output

Negative energy balance

Intake is less than output leading to weight loss

Positive energy balance

Intake is greater than output leading to weight gain

Pear-shaped body

Fat stored in hips and thighs with lower disease risk

Central-body obesity

Fat stored in abdomen with higher disease risk

Satiety

Feeling of fullness that suppresses hunger

Ghrelin

Hormone that stimulates hunger

Cholecystokinin (CCK)

Hormone that promotes fullness

Leptin

Hormone that reduces hunger and fat storage

Appetite

Desire to eat

Adipose cells

Cells that store fat, release energy, and regulate metabolism and hunger

Thyroid gland

Regulates metabolism through hormone production

Underactive thyroid

Lowers BMR causing weight gain and fatigue

Overactive thyroid

Raises BMR causing weight loss and sweating

Factors that increase BMR

Muscle mass, male sex, tall height, young age, fever, pregnancy, stimulants

Factors that decrease BMR

Less muscle, older age, shorter height, underactive thyroid

Thermic effect of food, physical activity, NEAT

Additional energy needs beyond BMR

Energy balance and weight

Negative balance causes weight loss, positive balance causes weight gain

BMI categories

Underweight <18.5, Normal 18.5-24.9, Overweight 25-29.9, Obese ≥30

Health risks BMI >25

Type 2 diabetes, hypertension, cardiovascular disease

Health risks BMI >30

Cancer, sleep apnea, fertility issues, surgery complications, premature death

Subcutaneous fat function

Insulation, protection, uneven distribution by sex

Visceral fat risk

Located around organs; linked to inflammation and chronic disease

Physiological factors of weight gain

Hormones, genetics, gut microbiota, hunger/satiety signals

Environmental factors of obesity

Sedentary lifestyle, large portion sizes

Psychological factors

Mood, stress, low self-esteem

Societal factors

Culture, body image, social media influence

Four elements of weight-loss plan

Motivation, calorie reduction, physical activity, behavior modification

Calorie reduction tips

Reduce sugar and fat, eat fruits/vegetables, track intake, avoid extreme dieting

Behavior modification eating tips

Plan meals, control portions, avoid impulse eating

Behavior modification activity tips

Walk more, take stairs, increase daily movement

Self-monitoring

Tracking food intake and behaviors

Rewards for behavior change

Use non-food rewards for progress

Changing negative thoughts

Stay positive and expect setbacks

Community-based programs

Structured weight-loss programs with support and guidance

Weight maintenance tips

Exercise daily, eat breakfast, weigh weekly, limit screen time

Weight-loss medications eligibility

BMI ≥30 or ≥27 with health conditions

Orlistat

Medication that reduces fat absorption

GLP-1 medications

Reduce appetite and help control weight

Gastric bypass

Surgery creating small stomach pouch and reduced absorption

Gastric banding

Surgery using a band to reduce stomach size

Fad diet

Quick-fix diet that is unsustainable and often unbalanced

Disordered eating

Irregular eating behaviors that may lead to eating disorders

Eating disorder causes

Genetics, psychological issues, cultural pressure, stressful events

Anorexia nervosa

Self-starvation leading to very low body weight and malnutrition

Bulimia nervosa

Binge eating followed by purging behaviors

Binge-eating disorder

Binge eating without purging, often leads to overweight/obesity

Eating disorder prevention

Promote body positivity, early identification, avoid teasing

Eating disorder treatment

Psychotherapy, nutrition support, medical care

Structured activity

Planned exercise like running or weightlifting

Unstructured activity

Daily movement like chores or walking

Physical fitness

Ability to perform activity without excessive fatigue

Intensity

Level of exertion during activity

Target heart rate zone

Heart rate range that reflects exercise intensity

Aerobic exercise

Sustained activity that raises heart rate (e.g., running)

Resistance exercise

Exercise that builds muscle strength (e.g., weightlifting)

Sedentary activity

Little to no physical movement

Flexibility exercise

Stretching activities to improve range of motion

Activities of daily living

Unstructured daily tasks like cleaning or shopping

Ergogenic aids

Substances or methods used to improve performance

Physical activity recommendations

150 min moderate or 75 min vigorous/week plus strength training twice weekly

Benefits of physical activity

Reduced stress, improved self-image, increased muscle, better heart health, lower disease risk

Factors influencing intensity

Duration, type of activity, body weight

Max heart rate formula

220 minus age

Target heart rate zone calculation

50-70% of max heart rate for moderate intensity

Physical activity pyramid

Aerobic exercise, strength training, flexibility, and daily movement

Primary nutrient for ATP

Glucose (carbohydrates)

Energy systems

Phosphocreatine (short), anaerobic glycolysis (short-term), aerobic metabolism (long-term)

Primary fuel high intensity

Glucose

Primary fuel low/moderate intensity

Fat

Athlete diet recommendations

High carbs, adequate protein, sufficient calories, normal fat intake

Energy bars

Contain nutrients but not quick energy source

Energy gels

Provide quick carbohydrates for energy

Energy drinks

Provide hydration, sugar, and electrolytes

Heat cramps

Painful muscle cramps with sweating and thirst

Heat exhaustion

Weakness, nausea, dizziness, heavy sweating

Heatstroke

Dry hot skin, confusion, high body temp; medical emergency

Caffeine pros

Increases alertness, delays fatigue, improves performance

Caffeine cons

Rapid heart rate, sleep issues, GI distress

Creatine

Increases muscle mass and strength but results vary

Chromium

Claims muscle gain but not effective and may be toxic

Ginseng

May reduce fatigue but does not improve performance

Good fitness plan

Includes cardio, strength, flexibility, and rest/recovery