Nutrient Dense Diet Part 2 Flashcards
what is metabolism?
total energy expenditure (TEE) = resting metabolic rate (RMR) + thermic effect of food (TEF) + physical activity energy expenditure (PAEE)
RMR (resting metabolic rate)
-energy used to maintain vital functions (heart, liver, brain, kidneys)
-includes muscle and adipose tissue
-ranges between 50-70% of TEE
TEF (thermic effect of food)
-increase in metabolism after eating
-accounts for 10% of TEE
PAEE (physical activity energy expenditure)
-includes exercise and non-exercise activity
-ranges between 15-30% of TEE
what is metabolism?
the sum of all chemical reactions in cells that provide energy for vital processes and for synthesizing new organic material
Metabolism and CICO: Calories In, Calories Out
the basic equation:
calories in, calories out (CICO) = calories in (food intake) - calories out (total energy expenditure)
common misconceptions:
-often oversimplified to imply that weight management is straight forward
-frustrating for those who struggle with weight management
inaccuracy in estimation
CICO for weight management
basic principle:
-weight gain = calories in > calories out
-weight loss = calories out > calories in
the problem is in the details
hormone driven homeostasis affects metabolism
this model is overly simplified and does not account for individual variations
difficulty in accurately measuring calories in and calories out
calories in
human error: most people, including dietitians, underreport caloric intake
inaccurate food labels: FDA reports up to 20% error in calorie counts on food labels
cooking & processing: cooking, chopping, blending foods can alter caloric availability
measurement issues: weighing food is more accurate but still not precise
micronutrient variability: different macros have carying caloric values and absorbability
calories out - total energy expenditure (TEE)
mifflin-st. jeor equation
accurate within 10% of calories, 82% of the time
limitations:
the equation is not 100% accurate. there’s an 18% chance of less accurate results
calories out - thermic effect of food (TEF)
how much metabolism increases after eating
macronutrient impact:
fat: 0-3%
carbs: 5 - 10%
protein: 20-30%
implications:
TEF makes up about 10% of total expenditure.
miscalculations in TEF can contribute to weight mgmt difficulties
calories out - exercise related activity thermogenesis (EAT)
calories burned during exercise
common challenges:
-inaccurate reporting of exercise duration & intensity
-wrist worn devices often provide inaccurate estimates of energy expenditure
additional considerations:
-EPOC (excess post-exercise oxygen consumption)
-over training can be as problematic as a sedentary lifestyle due to impacts to stress hormones
-activity factor used in “calories in” calculations are prone to error
-body’s natural tendency to maintain current weight
calories out - non exercise activity thermogenesis (NEAT)
calories burned through daily activities not related to exercise
common challenges:
-different tasks, frequencies, and body movements make it hard to track
-unconscious movements like fidgeting can add between 300-500 extra calories burned per day
large margin of error, estimating NEAT is alrgely guesswork
two sides of metabolism
anabolism & catabolism
drivers: calories, hormones, exercise, sleep, inflammation, mindset
common misconceptions:
“you have to eat fat to burn fat”
“eating fat makes you fat”
importance of nuance:
-understanding when a concept is valid and when it’s not
-providing meaningful education to clients
anabolism
the body uses energy to create more complex molecules
body’s capability:
-tissues can be added to or taken away
-involves recycling of proteins, glycogen, and adipocytes
key hormones:
-human growth hormone
-insulin
-insulin like growth factor (IGF-1)
-testosterone
-estrogen
insulin’s role:
-anabolic outcomes: glycogenesis, lipogenesis, muscle protein synthesis
-prevention of catabolism: signals the body to store energy
-risks of insulin absence: diabetic ketoacidosis (DKA)
catabolism
the body breaks down complex molecules to release energy
glucagon’s role:
-produced by the pancreas to stabilize blood sugar by breaking down stored energy
-inhibited by insulin and struggles in a high insulin environment
cortisol:
-increases during sustained stress
-mobilizes fat and glycogen but also stores fat
epinephrine/adrenaline:
-increases during acute stress
catecholamines, cortisol, and muscle protein
SAM (sympathetic-adrenal-medullary) axis:
-produces epinephrine/adrenaline
-precursor: amino acid phenylalanine
-active when stress presents as a challenge
HPA (hypothalamus-pituitary-adrenal) axis:
-produces cortisol
-precursor: cholesterol
-active when stress presents as a threat
important pieces to consider
outlook matters: how we perceive stress can shift our physiological response from threat to challenge, reducing the negative impacts of stress
chronic stress and catabolism: chronic stress, driven by cortisol, promotes a catabolic state that decreases muscle tissue and increases fat storage
counter-signaling: exercise and adequate protein intake can counteract the catabolic effects of chronic stress
internal stress: factors like systemic inflammation, toxicity, gut dysbiosis, and nutrient deficiencies also induce a stress response, increasing cortisol levels
caloric deficit = chronic stress: consistent caloric deficits increase cortisol levels
cortisol and insulin resistance: cortisol inhibits insulin, leading to insulin resistance. insulin resistance is problematic in the presence of high levels of insulin and insulin spiking foods
metabolism, homeostasis and nutritional therapy
metabolism & homeostasis:
-multiple factors regulate metabolism
-a straightforward guide to help clients understand weight mgmt
weight mgmt:
-more common client request
-to be discussed in the context of weight loss
weight mgmt
the complexity of weight shifts
adaptations and homeostasis:
how the body adapts to new environments and how this affects weight
variability in outcomes:
weight can shift dramatically, or not at all, depending on multiple factors
three basic categories:
-weight gain
-weight loss
-weight maintenance