Weight Management:
Nutrition & Physical Activity
Part I
Energy In:
Influences on Hunger

Hunger
 Physiological response to nerve signals
and chemical messengers
 Hypothalamus: control center in brain
 Many influences!


Satiation – signal stop eating
Satiety – satisfaction between meals;
signal not to eat
Energy In: Food Composition
Hunger vs. Appetite:
Internal vs. External Signals

Overriding hunger and satiety
 Stress eating

External cues
 Time of day, availability, sight, taste of
food

Environmental influences
 Examples?

Disordered eating
 Psychological influences and beliefs
Sustaining Satiation and
Satiety

Nutrient composition
 Protein is most satiating
 Low-energy density foods are more
satiating
 Why?
 High-fiber foods are more satiating
 Why?
 High-fat foods – strong satiety signals
Energy Out

We utilize energy from food for moving
body, fueling chemical reactions,
functioning of organs
 These functions generate heat

Thermogenesis
 Basal metabolism
 Physical activity
 Food consumption: digestion & absorption
 Adaptation
Components of Energy
Expenditure – Basal Metabolism


About two-thirds of energy expended in
a day
Metabolic activities
 All basic processes of life
 Basal metabolic rate (BMR)
 Varies greatly from one individual to the
next!
 Major influence that we can control:
amount of lean tissue
Components of Energy
Expenditure – Basal Metabolism
Components of Energy
Expenditure – Physical Activity

Voluntary movement of skeletal muscles
 Most variable component of energy
expenditure
 Amount of energy needed
 Muscle mass
 Body weight
 Activity

Amount expended depends on frequency,
intensity, and duration of activity
Components of Energy Expenditure
– Thermic Effect of Food

Acceleration of GI tract functioning in
response to food presence
 Releases heat

Approximately 10 percent of energy
intake
Components of Energy Expenditure
– Adaptive Thermogenesis

Adapt to dramatically changing
circumstances
 Examples: intense physical conditioning,
extreme cold, trauma, stress



Extra work done by body
Amount expended is extremely variable
Not included in energy requirement
calculations
Fat Cell Metabolism

Lipoprotein lipase (LPL) activity
 Storage of triglycerides
 Obese people vs. lean people
 Activity in varying body regions
 Men vs. women


Enzyme activity releasing and breaking
down fat: individual differences
LPL activity increases after weight loss
Causes of Overweight & Obesity
– Genetics & Epigenetics

Causative role of genetics
 Genetic influences do seem to be involved


Genetics may determine predisposition to
obesity
Epigenetics
 Gene expression influenced by:
 Diet
 Physical activity
 Satiety and energy balance
Causes of Overweight &
Obesity – Environment

Encountered daily circumstances
 Interaction between environment and
genetics (epigenetics)

Overeating
 Present and past eating and activity
patterns influence current body weight
 Availability
 Serving sizes
 Restaurant food
Causes of Overweight &
Obesity – Environment

Physical inactivity
 Life requires little exertion
 Modern technology
 Inactivity contributes to weight gain and
poor health
 Sedentary activities and weight gain
 DRI for prevention of weight gain
 60 minutes of moderate activity every day
Problems of Overweight and
Obesity – Health Risks

Three indicators
 BMI
 Waist circumference
 Disease risk profile
 Factors taken into account

Would weight loss be beneficial?
 Health status
 Motivation
Problems of Overweight and
Obesity – Health Risks

Overweight in good health
 Sometimes health is not the motivation for
weight loss

Obese or overweight with risk factors
 Two or more risk factors: weight loss
recommended

Obese or overweight with life-threatening
condition
 Clear recommendation to lose weight
Problems of Overweight and
Obesity – Perceptions & Prejudices

Most obese people do not
successfully lose weight and maintain
the loss
 Social consequences
 Jobs, school, and in social situations

Psychological problems
 Embarrassment
 Other feelings
Problems of Overweight and
Obesity – Perceptions & Prejudices
Problems of Overweight and
Obesity – Dangerous Interventions


Intervention dangers
Diet books and weight-loss programs
 Little success with weight loss
maintenance



Fad diets
Weight-loss products
Herbal products
 Laws for dietary supplements

Other gimmicks
Weight Loss Strategies

Successful strategies
 Small changes
 Moderate losses
 Reasonable goals
 Reasonable rate of weight loss


Benefits of modest weight loss
Incorporation of healthy eating and
physical activity
Weight Loss Strategies –
Eating Plans

Be realistic about energy intake
 Create an energy deficit, but
 Avoid restrictive eating
 Avoid rapid weight loss
 Goal: nutritional adequacy without excess
 Deficit of 500 to 1000 kcalories per day
 Greatly assisted by physical activity!!
 Breakfast frequency
 Inversely related to obesity
Weight Loss Strategies –
Eating Plans

Nutritional adequacy
 Minimum of 1200-1500 kcalories a day

Eat small portions
 Eat less calorie-dense food at each meal
 Feel satisfied, not stuffed: Hara hachi bu

Lower energy density
 Price of food vs. health cost
Weight Loss Strategies –
Eating Plans

Remember water
 Assistance with weight management

Focus on fiber-rich foods
 Low in energy and high in nutrients
 Require effort to eat
 Speed of food consumption

To fat or not to fat?
 Energy density vs. satiety
 See study!
Weight Loss Strategies –
Eating Plans

Select carbohydrates carefully
 Whole vs. refined
 Quality and quantity matter
 Artificial sweeteners
 Impact on energy intake

Watch for empty kcalories
 Fat, sugar, and alcohol
Importance of Physical Activity

Best approach to weight management
 Moderate physical activity plus activities of
daily life

Combination of diet and physical activity
 Lose more fat
 Retain more muscle
 Regain less weight

Reduction of abdominal fat
 Especially resistance and HIIT
 Cortisol connection
Weight Loss Strategies –
Physical Activity
Physical Activity

Body composition
 Fat decreases and lean body mass
increases
 Decreased abdominal fat=decreased
disease risk

Appetite control
 Delayed appetite
 Reduces eating in absence of hunger
 Emotional/stress eating
 Another cortisol connection!
Weight Loss Strategies –
Physical Activity

Psychological benefits
 Self-esteem
 Stress management

Choosing activities
 Ones you enjoy & are willing to do
regularly
 Increase energy-expending daily
activities

Spot reducing?
Weight Maintenance

Successful weight loss
 Plateau
 Appropriate goal at this point?
 Changing up physical activities

Sustained weight loss
 Takes more effort to prevent regain than to
prevent initial gain
 Increased lean body mass helps
Underweight


Affects no more than 5% of U.S. adults
Weight gain is a matter of health
 Individual matter


Weight gain may be difficult
Demand for energy contributes to
underweight
 Physical activity
 Growth and development
Weight-Gain Strategies

Key diet planning strategies
 Adequacy and balance

Energy-dense foods
 Regular meals daily
 Large portions
 Extra snacks
 Liquid meals (shakes)