Weight & Eating Behaviors: Comprehensive Notes

Mechanisms of Weight Change

  • Theory of Energy Balance

    • Proposes that weight change is a result of the balance between calories consumed through food and beverages and calories expended through physical activity and metabolic processes.

    • An energy surplus leads to weight gain, while an energy deficit results in weight loss.

  • Set-Point Theory

    • Rooted in homeostasis.

    • The body is thought to have a predetermined weight or fat-mass range.

    • Physiological mechanisms maintain the set point and resist deviation.

    • Ghrelin increases when on a low kcal diet, leading to increased hunger.

    • Weight loss leads to increased appetite and reduced metabolism.

    • Adipocytes shrink and leptin levels decrease.

    • Weight gain also triggers mechanisms, but they are weaker.

    • Asymmetrical defense favors weight regain.

    • Possible explanation of why weight is regained.

    • Life events or stages can change the set point over a lifetime, such as:

      • Childbirth

      • Menopause

      • Aging

      • Disease

Carbohydrate-Insulin Model

  • Higher intake of carbohydrates raises blood glucose (BG) levels.

  • The pancreas responds by increasing insulin secretion.

  • Insulin drives:

    • Uptake of glucose by cells.

    • Storage of glucose:

      • Glycogenesis (storage in the liver and muscle).

    • Use of glucose for ATP via glycolysis.

    • Lipogenesis into triglycerides (TGs) for storage.

  • Primarily driven by high Glycemic Index (GI) and/or high refined carbohydrate (CHO) intake.

  • Hormone response leads to Kcals unavailable for use by body cells (Ludwig, 2018).

Challenges in Sustaining Weight Loss

  • Weight loss is challenging to sustain at individual and population levels.

  • Initial weight loss (5-10%) is associated with improved health metrics, but people may be disappointed with this amount of loss regarding body image.

  • Diet changes are difficult to sustain.

  • People can feel frustrated and ashamed with challenges.

  • Providers' routine recommendations to try to lose weight without considering or discussing current or past efforts can result in healthcare avoidance.

Emerging Medical Interventions

  • Medications:

    • GLP-1 agonists (e.g., Ozempic (semaglutide), Victoza, Trulicity).

      • Mimic the action of glucagon-like peptide-1 (GLP-1).

      • GLP-1 is released by the gut after eating and signals satiety.

      • Decreases glucagon secretion.

      • Supports insulin secretion.

      • Slows gastric emptying.

      • Promotes satiety.

    • Similar class of medications: GLP-1/GIP receptor agonists (e.g., Mounjaro).

      • GLP-1 and GIP are both incretins.

  • Bariatric Surgery:

    • Post-surgery intake is limited.

    • Requires supplementation:

      • Iron

      • Vitamin B12

      • Calcium

      • Vitamin C

How Food Affects the Body

  • What we eat and how we move our bodies affect how we feel and function.

Principles of Healthy Eating

  • Adequacy

  • Balance

  • Variety

  • Moderation

  • Nourishment & Enjoyment

Theories of Behavior Change: Health Belief Model

  • Developed to understand why people adopt behaviors for disease prevention.

  • Key components:

    • Perceived susceptibility and perceived severity lead to perceived threat.

    • Modifying factors.

    • Cues to action.

    • Likelihood of behavior change.

Social Determinants of Health

  • Allostatic load:

    • Allostasis: The ability to achieve stability through change.

    • Cumulative health “costs” of exposure to stressors.

    • Impact of resulting behaviors like circadian rhythms, sleep disruption, lack of exercise.

  • Biology of allostatic load:

    • Primary mediators: Cortisol, adrenalin, hormones.

    • Associations with allostatic load (but not always):

      • Blood pressure

      • Waist-to-hip ratio

      • HDL and total cholesterol

      • Glycosylated hemoglobin (A1c)

Social Ecological Model

  • Systems-level considerations.

  • Important to consider the levels’ interactions and changes over time.

  • Influences on health behavior.

  • Combine with social determinants of health.

  • Consider nutrition-related components of each space and implications of this model on nutrition interventions.

Life Course Models

  • Interactions of exposure & time on health:

    • Critical periods: Exposure leads to disease.

    • Latency Accumulation models.

    • Chains of risk: Exposure influences disease and future exposures.

Transtheoretical Model

  • Behavior change occurs as a result of passing through sequential stages:

    • Pre-contemplation

    • Contemplation

    • Preparation

    • Action

    • Maintenance

Stage 1: Precontemplation

  • No intention to take action in the foreseeable future.

  • Unaware, uninformed, misinformed, frustrated/demoralized, or actively benefitting/entrenched.

  • Strategies:

    • Get the client to think.

    • Establish rapport.

    • Explore concerns and check in about understanding.

    • Elicit information.

    • Don’t move too far ahead of your patient/client.

    • Do not threaten or judge your patient/client.

Stage 2: Contemplation

  • Thinking about changing but reluctant and not actively changing yet.

  • Weighing pros and cons; information gathering.

  • Strategies:

    • Get the client to think.

    • Increase self-confidence.

    • Focus on pros of the behavior.

    • Identify & promote positive outcomes.

    • Use “Yes, and…” statements; be non-oppositional.

Stage 3: Preparation

  • Deciding to make the change with a commitment to future change; beginning of attempt to change.

  • Skills-acquisition or resource acquisition; approximately a 1-month timeline.

  • Strategies:

    • Clarify goals.

    • Reinforce personal choice.

    • Practice skills.

Stage 4: Action

Stage 5: Maintenance

  • Sustaining behavior change for approximately 6 months or longer.

  • Less vulnerable to relapse/interruptions.

  • Planning and support can continue to be helpful.

  • The transtheoretical model considers if change is linear, cyclical, or nonlinear, and if relapse occurs.

Eating Competence

  • Being positive, comfortable, and flexible with eating, as well as matter-of-fact and reliable about getting enough to eat of enjoyable food.

  • Absence of worrying about what and how much to eat.

  • Combination of structure & permission.

  • Components:

    • Feed Yourself Faithfully: Reliably prioritize and take time to eat.

    • Give yourself permission to eat.

    • Pay attention, notice, and learn.

Intuitive Eating

  • An approach to making food decisions that emphasizes:

    • Teaching individuals to become aware of their bodies.

    • Basing food choices on the physiological signs of hunger and satiety, not on emotional responses.

    • Discourages dieting.

  • Key components:

    • Unconditional permission to eat.

    • Eating to meet physiological and non-emotional needs.

    • Relying on internal hunger and satiety signals to establish what and how much to eat.

Food Literacy

  • Knowledge, skills, & attitudes for making informed decisions about food and its impact on health.

  • Includes:

    • Information & understanding.

    • Functional skills.

    • Critical thinking skills.

Mindful Eating

  • Awareness, limited distraction, non-judgment, pace, taste, satisfaction, enjoyment, presence, and attunement.

Health at Every Size

  • A framework for thinking about bodies, food, & health that de-emphasizes weight and the goal of weight loss.

  • Advocates for health outcomes and behavior change independent of weight change.

  • Focuses on hunger/fullness, biology, and attunement instead of prescriptive diets.

  • Challenges the dichotomy: thin = healthy vs. fat = unhealthy.

  • Accepts and respects diversity of body sizes.

Disordered Eating & Eating Disorders

  • Eating Disorders:

    • Binge eating disorder

    • Bulimia Nervosa

    • Anorexia Nervosa

What are Eating Disorders?

  • Definitions come from the Diagnostic and Statistical Manual of Mental Disorders (DSM).

  • Currently in its 5th revision (May 2013); definitions and criteria have evolved and will continue to evolve.

  • Includes: Anorexia Nervosa, Bulimia Nervosa, Binge Eating Disorder, ARFID, and OSFED.

Diagnostic Criteria: Anorexia Nervosa

  • Restriction of energy intake relative to requirements, leading to a significantly low body weight in the context of age, sex, developmental trajectory, and physical health.

  • Intense fear of gaining weight or becoming fat, or persistent behavior that interferes with weight gain.

  • Disturbance in one’s body weight or shape, self-worth influenced by body weight or shape, or persistent lack of recognition of the seriousness of current low body weight.

Diagnostic Criteria: Bulimia Nervosa

  • Recurrent episodes of binge eating.

  • Recurrent inappropriate compensatory behavior to prevent weight gain (purging).

  • Binge eating & compensatory behaviors both occur at least 1x/week for 3 months (on average).

  • Self-evaluation unduly influenced by body shape and weight.

  • Disturbance does not occur exclusively during episodes of AN.

Diagnostic Criteria: Binge Eating Disorder (BED)

  • Recurrent episodes of binge eating with loss of control.

  • Marked distress regarding binge eating.

  • Binge eating occurs at least 1 day/week for 3 months.

  • Not associated with regular use of inappropriate compensatory behavior.

  • Does not occur exclusively in the setting of AN or BN.

Other Specified Feeding or Eating Disorders (OSFED)

  • Atypical Anorexia Nervosa

  • BN of low frequency/duration

  • BED of low frequency/duration

  • Purging Disorder

  • Night Eating Syndrome

Atypical Anorexia Nervosa

  • All criteria for AN are met except that weight is within or above the normal range.

  • Often present for treatment after a longer duration and may not have access to higher levels of care.

  • Physiologic complications of malnutrition/starvation can be/are just as serious:

    • Concern for bradycardia

    • Hormonal disruptions

    • Nutrient deficiencies

  • Equally concerning for psychological impairment & quality of life.

What Causes Anorexia Nervosa?

  • The exact cause is unknown.

  • Biopsychosocial model:

    • Biological Risk Factors: Genetics, microbiome.

    • Psychological Risk Factors: Mental health & coping skills, trauma, comorbid disorders, traits (e.g., perfectionism).

    • Social Risk Factors: Thin ideal, family dynamics & food modeling, culture, comments.

First Nutrition Principles

  • Adequate, consistent meals.

  • Not starting with a caloric deficit.

  • Avoid meal skipping.

  • Incorporate snacks.

  • Identify and shift from “overly virtuous” patterns.

  • Balance of macronutrients.

  • Variety.

  • Education & strategies to interrupt black & white thinking.

  • “Moderation”.

  • Learning portions, permission, and feedback.

  • Introduction of challenging foods.

  • Enjoyment.