Obesity Trends and Metabolism Overview

Obesity Prevalence

• Worldwide, 1.9 billion adults and 41 million children under five are affected by obesity.
• In Saudi Arabia (2018), 24.1% of men and 33.5% of women were obese.
• Rising obesity rates are linked to a global food system that promotes energy-dense, processed, and affordable foods.

Childhood Obesity in Saudi Arabia

• In 2012, 15% of children under five were overweight and 6% were obese.
• For children five years and older, those figures were 23% overweight and 9.3% obese.

BMI and Overweight

• A BMI exceeding 25 indicates overweight.

Fat Cells

• Fat is stored in adipose tissue.
• Fat cell size and number increase with positive energy balance.
• Increased fat cell size triggers cell proliferation.
• Fat cell number remains constant during negative energy balance.
• People with extra fat cells easily regain weight.
• Ectopic fat (fat outside adipose tissue) disrupts normal metabolism, contributing to disease.

Fat Cell Metabolism

• Lipoprotein lipase (LPL) removes triglycerides from blood for storage in adipose tissue and muscle cells.
• Obese people have higher LPL activity in fat cells, making fat storage more efficient.
• This leads to a more dramatic impact of modest energy excesses on obese individuals compared to lean people.
• Women have higher LPL levels in breasts, thighs, and hips.
• Men have higher LPL levels in abdominal fat cells.
• After weight loss, LPL activity in adipose tissue increases, contributing to weight regain.

Types of Fat

• White adipose tissue stores fat for energy use by other cells.
• Brown adipose tissue releases stored energy as heat, defending against cold and preventing obesity.
  • Important in newborns and cold-exposed animals.
  • Brown fat activity declines with age and obesity.
• Brite adipocytes (beige adipocytes) are white fat cells with brown fat characteristics.
  • Contain active uncoupling proteins.
  • More abundant than brown fat cells in adults.
  • Physical activity triggers browning (transformation of white fat cells into brite fat cells).

Set-Point Theory

• After weight loss, the body adjusts its metabolism to favor weight regain.
• This decrease in metabolic rate is greater than expected based on body composition alone.

Causes of Overweight and Obesity

• Genetics and Epigenetics:
  • Genes influence energy balance and satiety pathways.
  • Environmental factors like diet and activity affect gene expression.
  • Epigenetics can influence gene expression without changing the genome.
  • Genetics may determine a person's susceptibility to obesity.

Obesity Gene (ob)

• Expressed primarily in adipose tissue.
• Codes for leptin (satiety hormone).
  • Acts on the hypothalamus.
  • Promotes negative energy balance and weight reduction.
  • Suppresses appetite and increases energy expenditure.
  • Leptin levels increase with body fat.
  • Leptin sensitivity decreases (leptin resistance).
  • Leptin injections reduce body weight in animals and humans.
• Rare genetic deficiency of leptin or receptor mutation in humans.

Ghrelin

• Hormone secreted by stomach cells.
• Hunger hormone.
• Acts on the hypothalamus.
• Increases appetite.
• Promotes positive energy balance and weight gain.
• Influenced by psychological mindset and sleep:
  • Lack of sleep increases ghrelin and decreases leptin.

Environmental Factors

• Obesogenic environments: daily circumstances that promote fatness.
• Overeating:
  • Past and present eating and activity patterns influence weight.
  • Food availability and portion sizes play a role.
  • Restaurant food often features large portions.
• Physical Inactivity:
  • Modern technology has replaced physical activity.
  • Sedentary activities require little energy and replace time for more vigorous activities.
  • Watching television is linked to increased food purchases and snacking on unhealthy foods.
  • People need physical activity to consume enough nutrients without weight gain.
  • The DRI suggests 60 minutes of moderate-intensity physical activity daily, in addition to daily living activities, to prevent weight gain.

Consequences of Obesity

• Social consequences:
  • Discrimination in jobs, school, and social situations.
  • Judged by appearance over character.
  • Negative stereotypes, such as laziness and lack of self-control.
  • Discrimination may worsen overeating.
• Psychological problems:
  • Embarrassment, rejection, shame, and depression.

Health Risks

• Weight loss is recommended for obese individuals (BMI ≥ 30) and overweight people (BMI 25-29.9) with:
  • Hypertension
  • Fatty liver disease
  • Abnormal blood lipids
  • Diabetes or prediabetes
  • Sleep apnea

Dangerous Weight-Loss Interventions

• Diet books and weight-loss programs:
  • Often ineffective and rely on deceptive claims and testimonials.
• Fad diets:
  • Popular plans promising quick weight loss, severely limiting certain foods or overemphasizing others.
  • Examples include avoiding potatoes or pasta, or consuming cabbage soup daily.
• Weight-loss products:
  • Herbal and dietary supplements:
    • Safety and effectiveness cannot be assumed.
    • Do not require FDA approval.
    • Often contain undeclared ingredients.
    • Can have serious consequences like seizures and heart attacks.
• Other gimmicks:
  • Hot baths to speed up metabolism can lead to dehydration.

Weight-Loss Strategies

• Successful treatment combines:
  • Healthy eating, physical activity, supportive environment, and psychosocial support as first-line therapy.
• Reasonable rate of weight loss:
  • 0.25 to 1 kg/week.
  • 5 to 10 percent of body weight over 6 months.
    • More sustainable than rapid weight loss.
    • Modest losses improve disease-related factors, such as blood glucose, blood pressure, and lipids.
  • Daily balanced eating and activity are crucial.

Eating Patterns

• No single food plan is magical.
• Consistency in eating is essential for successful weight maintenance.
• Preventing weight gain is easier than losing weight.
• Both weight loss and prevention involve similar strategies.
• A major difference is the focus on developing beneficial eating and activity habits early in life to prevent unhealthy habits.

Benefits of Physical Activity

• Exercise changes body composition, decreasing fat mass and increasing lean mass, even without weight loss.
• Exercise suppresses appetite, inhibiting inappropriate appetite driven by boredom or anxiety.

Behavior and Attitude

• Behavior modification:
  • Adopt a positive and proactive attitude.
  • Incorporate healthy eating and activity into daily routines.
• Becoming aware of behaviors:
  • Keep a record of behaviors.
• Changing behaviors:
  • Avoid shopping for food when hungry.
  • Avoid eating while watching television.

Cognitive Skills

• Successful behavior change depends on:
  • Problem-solving and cognitive restructuring to replace negative thoughts.
  • Other health behaviors.
• Personal attitude:
  • Understand the personal relationship with food.
  • Identify triggers for overeating.
  • Problem-solve to change responses to triggers.
• Support groups:
  • Seek support from others.

Drug Treatment for Obesity

• Strategies vary based on obesity level and disease risk.
• Drugs can contribute to weight loss as part of a comprehensive, long-term plan.
• FDA approval criteria: Benefits must clearly outweigh the risks.
• Orlistat (Xenical):
  • Inhibits pancreatic lipase in the GI tract, blocking fat digestion and absorption for reduced energy intake.
  • Side effects: GI cramping, diarrhea, gas, frequent bowel movements, reduced fat-soluble vitamin absorption, rare cases of liver injury.

Surgical Treatments for Obesity

• Surgery may be considered for individuals who:

  • Cannot lose weight through diet and exercise.
  • Have a BMI ≥ 40 or ≥ 35 with obesity-related health problems like diabetes or hypertension.
  • Have no contraindications (medical or psychological).
  • Understand the risks and are committed to post-surgery treatment.

• Surgeries reduce stomach size, limiting food intake.

Explore the global and childhood obesity statistics, particularly focusing on Saudi Arabia. Understand the implications of BMI, fat cell development, and metabolic disorders related to obesity. This quiz delves into the factors contributing to rising obesity rates and how fat cells affect overall health.