Chapter 22 Nutrition in Weight Management

Fat mass
fat from all body sources including brain , skeleton and adipose tissue
Fat-free mass (FFM)
includes water, protein, and mineral components; proportions differ between individuals
Lean body mass (LBM)
Muscle;
Higher in men than women, increases with exercise and decreases in older adults
What is the major determinant of RMR?
LBM!; decrease in LBM can hinder weight loss
To achieve long-term weight loss, loss of fat mass while maintaining _____ and _____ is desirable
FFM and RMR
What is the most variable component of LBM?
Water! (60-65% of body weight); state of hydration induces several pound weight fluctuations
Essential fat
-necessary for normal physiologic functioning
-stored in small amounts in bone marrow, heart, lung, liver, spleen, kidneys, muscles and nervous system
-Men – 3% is essential
-Women – 12% is essential (breasts, pelvic regions, thighs)
Storage Fat
-energy reserve; mainly TG’s in adipose
-accumulates under skin, around internal organs
-most is expendable
Total body fat associated with optimal health
M: 10-25%
W: 18-30%
White Adipose Tissue (WAT)
stores energy as repository for TBs, serves as cushion to protect abdominal organs, insulates body to preserve heat
(carotene gives it yellow color)
Brown Adipose Tissue (BAT)
-rapid source of energy for infants; 5% of their body weight
-brown color due to extensive vascularization for energy and heat production
Adipocyte
-mature fat cell
-lipid droplet surrounded by thin cytoplasm containing nucleus and mitochondria
-store fat = to 80-95% of their volume
Hyperplasia
increased number of cells
occurs as normal growth process during infancy and adolescence
Adiposity rebound
increase in body fat around 6 years of age; rebound before 5.5 years is predictive of higher level of adiposity going into adulthood
Hypertrophy
increased cell size
can expand 1000x
numbers of fat cells do not decrease
Weight loss of what % is required to decree fat cell size?
5%
Semivolatile organic compounds (SVOCs)
-Accumulate in adipose tissue from exposure to toxins, chemicals and pesticides
-Interfere with key weight control mechanisms of the body (alter metabolism, disrupt endocrine function, damage mitochondria, increase inflammation, alter circadian rhythms, stress…)
What moves lipid from the blood into the adipose cell?
lipoprotein lipase (LPL)
What does LPL do?
moves lipid into the adipose cell from the blood and hydrolyzes TG into FFA and glycerol
How do hormones affect LPL activity?
-Sex hormones are present – normal distribution of fat
-Decrease in sex steroid hormones (menopause/gonadectomy) –> increase in central obesity
Activity Thermogenesis (AT)
-energy expended in voluntary activity
-most variable component of energy expenditure
~15-30% of TEE
How much of TEE is explained by RMR?
60-70%
NEAT
Nonexercise activity thermogenesis
-energy expended for everything that is not sleeping, eating, sports-like activity
-can vary up to 2000kcal/d between individuals
What % of people in the US versus Canada are overweight?
66% vs 36%
What % of people in the US vs Canada vs Europe are obese?
32%, 23%, 15-25%
Causes of overweight and obesity
Hereditary
Lack of PA
Inflammation
Lack of sleep, high stress, circadian rhythm
Pleasure in taste, less responsive to satiety, unrealistic meal portions
“Obesogens”
Viruses, pathogens, microflora
When FFA are needed by other cells, what enzyme hydrolyzes them once again (after esterification in adipocytes)
Hormone-sensitive lipase (HSL)
How are children able to overcome over- and underfeeding?
Hypophagia (undereating) and Hyperphagia (overeating)
Long-term regulation of weight seems to involve a feedback mechanism using what protein signals?
adipocytokines; released when ‘normal’ body composition is disturbed
Insulin
moves glucose into cells (out of blood)
Leptin
contributes to long-term fullness by sensing body’s overall energy stores
Adiponectin
made by fat cells; helps body respond better to insulin by boosting metabolism
Ghrelin
the hunger hormone!
Overweight =
BMI 24.9-29.9 (elderly 27-30)
Obese =
BMI > 30
Waist Circumference that indicates health risk
M: >40 in
W: >35 in
Waist Circumference correlates with ???
cardiovascular risk including:
-hypertension, atherosclerosis, heart disease, stroke risk
WHR
Waist hip ratio
-waist smaller than hips is positive for heart health
-GOAL: M (<1) W (<.8)
NAFLD
Non-alcoholic fatty liver disease
-associated with obesity
-progresses to end stage liver disease if
Optimal BMI range for longevity
20.5-24.9
Risk factor for cancer, infertility, poor wound healing, poor antibody response to hep B vaccine…
Obesity
Common comorbidities of obesity
T2DM, HTN, Stroke, certain cancers, infertility…
Two major types of fat deposition
Android
Gynoid
Android
apple-shaped; men and post-menopausal women; more commonly experience impairments in glucose metabolism
Gynoid
pear-shaped; women; excess gluteofemoral fat in thighs and buttocks; support demands of pregnancy and lactation
Visceral Adipose Tissue (VAT)
under peritoneum and in intraabdominal cavity; highly correlated with insulin resistance
Metabolic Syndrome dx criteria
Must have 3 or more of the following
-waist circ >35in (w) >40in (m)
-serum TG at least 150mg/dL
-HDL less than 40mg/dL (m) 50 (w)
-BP >135/85mm Hg
-fasting glucose 100mg/dL or higher
low level of VAT and high level of CRF equates to what?
cardiometabolic health!
Lifestyle modification
best treatment for obesity
Goal of obesity treatment
weight management; attaining the best weight possible in the context of overall health
Obese persons who lose what % of body weight are likely to improve which biomarkers?
5-10%; blood glucose, BP and cholesterol levels
Why is mobilizing fat the most efficient form of weight loss?
Twice the kcal of protein; spares LBM
-wt loss over a longer period achieves this
Why do men reduce weight faster than women?
higher LBM and RMR
Lifestyle modification strategies
1. Easy to achieve short-term goals
2. Self-Monitoring
3. Stimulus Control
4. Confronting Barriers
5. Sleep and stress mgt
6. Social support
7. Contracting
Example of ‘easy to achieve short term goal’
“include one fruit at lunch”
” trim regular food portions”
Example of ‘self-monitoring’
“use a food and activity log”
“perform a regular weigh in”
Example of ‘stimulus control’
“shop when not hungry and with a list”
“avoid distractions during meals”
Example of “confronting barriers”
“practice problem solving steps”
“plan ahead”
Example of social support
attend organized support groups
use family, friends and co-workers as support systems
For which level of overweight/obese is surgical intervention (sometimes) appropriate?
morbid obesity (BMI>40)
General guidelines to treat obesity
1. low cal diet, increased PA and life-style modification
2. the preceding + pharmacotherapy
3. Surgery + individual dietary regimen, PA and LM
4. Prevention of weight regain via energy balance
Restricted Energy Diets
Deficit of 5-1000kcal daily in order to mobilize fat stores to meet daily energy needs
-diet is nutritionally adequate EXCEPT in calories
-Extra fiber is recommended to improve satiety, slow gastric-emptying and reduce caloric density
Formula Diets/Meal-Replacements (who are they appropriate for?)
good for ppl who have difficulty with self-selection or portion control
Commercial Programs (of merit)
Weight Watchers is the only one with substantial supportive evidence
Extreme Energy Restriction/Fasting
<200kcal per day; usually short term enough that physiological changes that accompany starvation are not seen; more than 50% of weight lost is fluid--> hypotension can result; also, gout and gallstones
VLCD
Very low cal diets
-provide 200-800kcal
-little evidence to support
-rich in protein (.8-1.5g/kg IBW)
-designed to include full complement of vit/min etc
-generally 12-16weeks
-reserved for those with BMI>30
-generally negative side effects
-no significant differences in long-term weight loss
Moderate-fat, balanced nutrient reduction diets containing 20-30% fat, 15-20% protein and 55-60% CHO; focuses on energy density of foods
Volumetrics
Very low fat diets <10% of cals from fat; very restrictive
Dr. Dean Ornish’s Program for Reversing Heart Disease
The Pritikin Program
Severe carb restricted diets
Dr. Atkins’ New Diet Revolution
The Carb Addict’s Diet
The Zone Diet
South Beach Diet
-weight loss ensues because of cal restriction, not small insulin ranges
Most variable component of EE
physical activity (activity thermogenesis)
Why is PA so important in weight loss?
Helps balance the loss of LBM and reduction of RMR that inevitably accompany intentional weight reduction
-also expend additional energy and increase sensitivity to insulin
Adequate levels of PA as recommended by USDA
60-90min daily
Aerobic benefits; Resistance Training Benefits
CVHealth through elevated RMR, cal expenditure, energy deficit and loss of fat; increase LBM and RMR + ability to use more of the energy intake and increases BMD
What BMI should one be to use appropriate pharmacotherapy?
30+ or 27 with comorbidities or significant risk factors
What does pharmacotherapy help in weight management?
Decrease appetite, reduce absorption of fat, increase energy expenditure
Categories of CNS-acting agents
Catecholaminergic and serotoninergic
Side effects of CNS-acting agents
dry mouth, headache, insomnia and constipation
What are the only medications approved by the FDA for weight loss?
Orlistat and Sibutramine
Which CNS-acting agents are not recommended for obesity treatment?
Catecholaminergic – act on the brain
Serotoninergic agents: action and examples
-act by increasing serotonin levels in the brain
-fenfluramine
-dexfenfluramine
-both have been removed from the market
Sibutramine
-combination of catecholaminergic and seritoninergic
-inhibit the reuptake of serotonin and norepinephrine in the CNS to increase satiety, reduce hunger, and lessen drop in metabolic rate that occurs with wt loss
-stimulates sympathetic nervous system and may have CV effects
Who is Sibutramine not appropriate for?
-CV disorders
-use with certain antidepressants (MAOI)
(hypertensive crisis may occur)
Orlistat
-inhibits gastrointestinal lipase, which reduces ~1/3 of the amount of fat absorbed from food
-supplements are typically recommended, separated from the drug by 2 hours bc of lower fat-soluble vitamin absorption
Side effects of Orlistat; benefits of Orlistat
increased fecal urgency
oily spotting
flatus with discharge

reduced LDL, increased HDL, improved glycemic control, reduced blood pressure
Only OTC weight loss product
Alli- contains half the prescription dose of Orlistat
Non-diet Paradigm
body will attain its natural weight if the individual eats healthfully, becomes attuned to hunger and satiety cures and incorporates physical activity
-focuses on achieving health not a number
-advocates promote size acceptance and respect for diversity of body shapes and sizes
accepted form of treatment for the extreme/class 3 obese
Bariatric surgery
Failure of what criteria must be met before consideration for bariatric surgery?
-CR, exercise, lifestyle modification, psych counseling, family involvement (inability to reduce body fat by 1/2 and wt by 1/3
Diet progression after Gastric Bypass
liquid->semisolids/puree->soft foods->regular small meals/snacks (6wks total)
Gastroplasty
reduces size of the stomach by applying rows of stainless-steel staples to partition the stomach and create small gastric pouch, leaving only small opening into distal stomach; banded by a piece of mesh
Most popular surgery…
Vertical banded gastroplasty
Gastric banding
band creating the reduced stomach pouch can be adjusted so that the opening to the rest of stomach can be made smaller or enlarged; will not require folic acid, b12 or iron replacements!
Gastric Bypass
-reduces size of stomach with the stapling procedure
-connects small opening in the upper portion of the stomach to the small intestine (intestinal loop)
Side effects of Bypass
“dumping syndrome”, tachycardia, sweating, abdominal pain, bloating of the pouch, nausea, vomiting (food record can help to avoid certain foods; must be monitored and supplements are necessary
Liposuction
-aspiration of fat deposits by means of a 1-2cm incision through which a tube is fanned out into the adipose tissue
-successful operations are normally of younger persons with only small amts of fat to be removed
-considered cosmetic surgery because only 5lb of fat are removed at a time
yo-yo effect
ups and downs in weight loss and regain
“weight cycling”
result in net increase in body fat: increased risk for hyperlipidemia, HTN, diabetes and osteoarthritis
Energy requirements for weight maintenance after weight reduction are _____% lower than original weight
25
To maintain their weight loss, the NWCR participants did what?
1. Eat a relatively low fat diet (24%)
2. Eat breakfast almost every day
3. Weigh regularly
4. Engage in high levels of PA (60-90min/day)
After maintenance of weight loss for _____ years, chance of longer-term success is greatly improved
2 to 5
Plateau Effect
Theories
1. reduction of lipid in individual adipocytes to some level that signals metabolic adjustment and weight maintenance
2. release of toxins from adipose tissue that act as endocrine disruptors and inflammatory agents (SVOC’s)
—-
LBM decreases as does RMR
Primary goal of treatment of children
healthy eating and activity (not IBW)
Children under 7…
weight maintenance or slowing of weight gain; allows for decline in BMI as height increases; if secondary complications are present, children in this age group may benefit from weight loss
What is the proper MNT for a child already exceeding an optimal adult weight?
slow weight loss of 10-12lbs per year until optimal adult weight is reached
Underweight or unintentional weight loss can be caused by…
1. inadequate oral food and bev intake
2. excessive PA
3. inadequate capacity for absorption and metabolism of foods consumed
4. a wasting disease that increases metabolic rate/energy needs
5. excess energy expenditure during psychological or emotional stress
High Energy Diets (composition…)
Meals should be scheduled and relaxed
Must be encouraged to eat, even if not hungry
Snacks are necessary
Liquid supplements with or between meals is often effective
30% fat
12-15% protein
Basic vitamin/mineral supplement may be encouraged
500-1000 extra kilocalories per day
Increase intake gradually