Transcript Obesity and Energy Balance

Advanced Healing Methods
GCU Holistic Health
Fall 2009
Obesity
 Surgeon General: “Overweight and obesity result from
excess calorie consumption and/or inadequate
physical activity.”
 US, 1970’s to 1990’s: increased caloric intake
 NHANES- 1971 to 2000- 150 calories per day in men, 350 in
women
 USDA- 1971 to 1982: 3300 calories per day per person
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1993-1997: 3800 calories
90% of the 500 calories from carbs
 The rise in obesity also coincides with increasing exercise
The Pima Indians
 Highest rates of obesity and diabetes in the US
 NIH: “As the typical American diet became more
available on the reservation after the war (WW II),
people became more overweight.”
 “If the Pima Indians could return to some of their
traditions, including a high degree of physical activity
and a diet with less fat and more starch, we might be
able to reduce the rate, and surely the severity, of
unhealthy weight in most of the population.”
The Pima Indians
 Early 19th century and before
 Game, fish, clams, corn, beans, cattle, poultry, wheat, melons, figs,
cactus
 1846: “Sprightly… in fine health… the greatest abundance of food”
 1860’s: “Years of famine” as white and Mexican settlers came in
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Game hunted nearly to extinction, water taken by the whites
 1890’s: government rations to avoid starvation
 1900’s: “Real obesity is found almost exclusively among the
Indians on reservations”
 The rations- 50% of calories from sugar and flour
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1950’s: “large quantities of refined flour, sugar, and canned fruits high in
sugar,” also soda, candy, chips, cakes
1962: “soda pop is used in immense amounts”
Energy Balance
 First Law of Thermodynamics
 A calorie is a calorie, calories in = calories out
 Change in energy stores = energy intake – expenditure
 Weight gain accompanied by positive energy balance
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But not necessarily caused by it
 Two possibilities
 Overeating and inactivity cause obesity
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“Willful descent into self-gratification”
 The obese responsible for their condition
 Character defect- they overeat and won’t change
 Willpower is the cure
Like alcoholism from overdrinking
 Metabolic imbalance induces overeating and inactivity,
resulting in obesity
Energy Balance
 Diseases of civilization associated with obesity
 2 hypotheses
 Obesity causes or worsens the conditions of metabolic
syndrome and the diseases of civilization

And obesity caused by overeating, particularly a high-fat diet, and
inactivity, so low-fat diet to fix
 The same metabolic imbalance that drives us to fatten also
causes metabolic syndrome and the diseases of civilization
 Hormonal (metabolic) effects on weight
 Positive caloric balance in children

Eating because they’re growing- hormone-driven
 Weight gain in pregnancy hormonal
 Height genetic and driven by hormones
 All of these induce a positive caloric balance
The Low-Fat Diet
 Low-fat, high-carb diets recommended for weight loss
 Fats fatten us the most effectively (in this view)
 Evidence
 Association between CVD, DM, and obesity
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
If high-fat diets cause CVD, and if CVD, DM, and obesity move
together in populations, then the high-fat diet causes all three
But there is no strong evidence for this!
 Rats become obese on a high-fat diet
 But only susceptible strains- others don’t
 And even these will grow fatter on high-fat, high-carb than on
high-fat, low-carb
 And rats will also fatten when fed sugar
 As will other animals, like pigs (who digest most like humans)
 Rats get obese on unlimited grocery food
 But they choose the high-carb food, not the high-fat, low-carb
food
The Low-Fat Diet
 Low-fat, high-carb diets recommended for weight loss
 Evidence
 The density of fat cals fools people into eating too many
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Fats have 9 calories/gram, while carbs (and proteins) have 4 apiece
 So eating the same amount of food as fat rather than carbs results in increased
calorie intake
Theory- we match intake to output by simple mechanisms like limiting the
volume of food intake
 So fiber-rich veggies fill our stomachs with indigestible cals
But- rat diets diluted with water, fiber, and clay
 Rats keep eating until they get their usual caloric intake
 90% of daily cals put into stomachs, and they stop eating
 But not when water put in
 Rats adjusting intake in response to calories, not volume, mass, or taste
 So- obesity as a defect of behavior ?
 Hunger and satiety dissociated from underlying metabolism
 That hunger might be a communication from the body about
underlying conditions is rarely considered
Studies
 Low-cal semi-starvation diets
 “Balanced” diets with fewer
calories
 Benedict 1917
 2 groups of 12 men, 1400-2100
calories per day, 3 mos
 Weight loss
 Constant hunger, feeling cold
 Metabolism slowed 30%
 Anemia, weakness, loss of
concentration, loss of libido
 Weight gain on any more
than 2100 cals
 Binge eating after study, all
weight regained in 2 weeks
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And another 8 lbs extra in the
next 3 weeks
 In general- 25% lost 20 lbs, 5%
lost 40 lbs
 Almost all gained it back
 Keys 1944
 32 male conscientious
objectors
 24 weeks on “semi-starvation”
diet- 1570 calories

400 cals protein, 270 fat, 900
carbs
 Also 5-6 mile walk each day
 12 lbs lost in 12 weeks
 Another 3 the next 12 weeks
 Slow nail growth, hair loss,
increased wound healing time,
metabolism down, slowed
reflexes, depression,
irritability, feeling cold
 Constant hunger, fixation on
food, cheating on diet
 When allowed to eat, 8000
cals per day
 Total weight gain 10 lbs
Exercise
 Jean Mayer, 1950’s- inactivity causes obesity
 But correlation is not causation
 Two questionable studies, never replicated

“J. Mayer has since demonstrated, in both animal and human
studies…”
-J. Mayer
 Or… exercise burns calories but stimulates appetite
 “Consistently high or low energy expenditures result in
consistently high or low levels of appetite.”

Hugo Rony, 1940
 1998: “Energy intake can be interpreted as a crude
measure of physical activity.”
Exercise
 Björntorp 1973- 7 subjects, 6 months of exercise three times a
week, no change in weight
 Pi-Sunyer 1989- weights can go up, down, or remain steady
 Denmark 1989- sedentary people trained to run marathons for 18
months
 18 men lost 5 lbs, 9 women lost no weight
 Randomized trials show less effect
 Somewhere between 3 ounces a month gained and 2 ounces a
month lost
 Animal experiments- the more the rats run, the more they eat,
weights unchanged
 In hamsters and gerbils, voluntary running produced increases in
body weight and body fat
 Hunger increases in proportion to the calories expended
 “Working up an appetite”
Fattening Diets
 To fatten- excess calories have to be stored as fat
 Not stored as muscle, not burned in metabolism or physical activity
 Continuing excess calorie consumption
 Massa tribe- Cameroon- fattening ritual
 Normally- milk as staple, 2500 calories per day
 To fatten- milk with sorghum porridge, 3500 cals/day
 Typical gain 15-20 lbs.
 Fattening by adding carbs
 Sumo wrestlers
 Normal Japanese diet 2300 cals/day
 Upper group- 5500 cals/day, 57% carbs, 16% fat
 Lower group- fatter, less muscular
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5100 cals/day, 80% carbs, 9% fat
 Overfeeding studies- 10,000 calories of mostly carbs a day, but
hunger late in the day
Reducing Diets
 AHA- carb restriction today is a “fad diet”
 But this was the standard medical treatment for obesity
through most of the 20th century- p. 314
 The AHA recommended high-carb, low-fat diets for CVD in
the 1960’s, then for obesity, and low-carb diets were
marginalized
 Observation- the obese eat more carbs
 Denmark 1936
 21 obese patients, 2 years
 1850 calories/day, 25% carbs, 60% fat
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Cream, butter, olive oil, eggs, cheese, meat
2 lbs weight loss per week, no chronic hunger or fatigue
Reducing Diets
 Donaldson 1920’s: 6 oz meat, 2 oz fat, at each meal,
no sugar, flour, alcohol, starch, ½ hour walk
 17K patients, 2-3 lbs/wk loss, no hunger
 Alfred Pennington- DuPont 1949: 20 execs, 9-54 lbs
loss, 2 lbs/wk, no hunger, increased physical energy
and sense of well-being
 No calorie restriction- min 2400, avg 3000
 Carbs restricted to 80 cal/meal
 JAMA and Lancet: “Freak Diets!” (p. 331)
 Thorpe 1957- rapid weight loss (6-8 lbs/mo), no
hunger, weakness, lethargy, or constipation
Reducing Diets
 Ohlson and Young 1952: 14-1500 cals/day, 24% protein,
54% fat, 22% carbs
 7 women, overweight to obese, 16 weeks, 19-37 lbs lost
 No hunger, addition of muscle mass
 16 overweight women, 9-26 lbs lost in 10 weeks, no
hunger, “unexpectedly healthy,” sense of well-being
 8 overweight male students, 1800 cals/day, 9 weeks, 1328 lbs lost, almost 3 lbs/week
 Leith 1961: 48 patients who had tried and failed with
low-cal diets, 28 lost btw 10 and 40 lbs
 “The patients ingested protein and fat as desired”
Reducing Diets
 Wilder 1930’s: a few hundred cals/day, meat, fish, egg white, 80-100 cals
of green veggies- weight loss without hunger
 Bistrian 1970’s: 700 patients, 50% fat, 50% protein, 650-800 cals/day,
weight loss without hunger
 1000, 1200, 1320, 1400, 1800, 2200, 2700, or no calorie restriction at allweight loss without hunger
 Kemp 1956: low-carb diet, no calorie restriction
 1450 overweight and obese patients
 49% lost at least 60% of excess weight- 25# after 1 year
 38% defaulted, 13% didn’t lose weight
 Carb restriction usually does a lot better than low-cal “balanced diet”
when compared directly, even when the low-carb diet has more
calories- p. 337
 6 recent trials- weight loss after 3-6 mos was 2-3x greater on low-carb,
calorie-unrestricted diet than on calorie-restricted, low-fat diet
 JAMA 2003: “Greater weight loss than higher-carbohydrate diets”
 37# vs. 4#, p. 339
Reducing Diets
 “If the Pima Indians could return to some of their
traditions, including a high degree of physical activity and
a diet with less fat and more starch, we might be able to
reduce the rate, and surely the severity, of unhealthy weight
in most of the population.”
 Obesity is a “penalty for living off the fat of the land rather
than the carbohydrate”
 But- start with an 800-calorie fat and protein diet
 Add 400 more calories of fat and protein for a low-carb weight
loss diet
 Add 400 carb calories, though, and get a “balanced” low-cal semistarvation diet
 50X less effective for weight loss
Reducing Diets
 Low-carb diets
 One fear is that the brain needs glucose
 130 grams of carb the “minimum safe levels”
 But if there’s less than 130 g, the liver makes ketone
bodies to supply brain
 And if no carbs at all, 75% of CNS fuel from ketones
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The rest from glucose made from amino acids or glycerol
Protein from diet or muscle
 Ketosis- normal- 5-20 mg/dl in 5-10% carb diet
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Diabetic ketoacidosis- pathological- 200 mg/dl
Reducing Diets
 V. Stefansson- early 20th century
 Lived with the Inuit for 10 years eating only meat
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He and the Inuit were vigorously healthy
So is the Inuit diet balanced?
 Conventional wisdom- balanced diet the best
 Need carbs for brain glucose
 And to prevent deficiency diseases
 Deficiency diseases
 Scurvy- vitamin C
 Pellagra- niacin (vit B3)
 Beriberi- thiamine (vit B1)
 Rickets- vitamin D
 Anemia- iron, vit B12, folate
 Fresh fruits and veggies to prevent
Reducing Diets
 All-meat diets considered unhealthy
 Raise BP, cause gout
 Monotonous
 Deficiency diseases
 Kidney damage
 1928- Stefansson and Anderson
 Ate only meat for an entire year
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79% fat, 19% protein, 2% carb (glycogen in muscle)
 Ketone bodies in urine to rule out carb cheating
 Both in good condition afterward
 6 and 3 lbs weight loss, BP decrease, no kidney damage, no gout, no
vitamin or mineral deficiencies, a case of gingivitis cleared up
Reducing Diets
 Deficiency diseases
 Studies all done with high-carb diets low in meat and
dairy- p. 321
 Meat contains all essential amino acids
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And 12 of 13 essential vitamins
All in large quantities and in high-utility forms
 Vitamin C- only small amounts in meat
 So scurvy can be cured by adding fruits and veggies
 But this doesn’t mean that the lack of these causes it!
 Inuit- no fruits, no veggies, no scurvy
 Could it be that carbs, esp refined carbs, increase our need
for vitamins?
Reducing Diets
 Deficiencies
 B vitamins depleted by carbs in diet
 Vitamin C also
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30% lower levels in type 2 DM
Lower vit C in metabolic syndrome too
Vitamin C deficiency as a disease of civilization?
 Mechanism- “biologically plausible and empirically evident”
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High blood glucose and/or high insulin increase the body’s
requirements for vitamin C
Vit C similar structure to glucose, transported into the cells by the same
insulin-dependent mechanism
Glucose and vit C compete, glucose greatly favored
So vitamin C uptake inhibited in high blood glucose
Glucose also impairs kidney reabsorption of vit C
Insulin infusions also cause vit C levels to fall
So… carbs flush out the vitamin C and inhibit us from using it
So absence of fruits in scurvy, or presence of refined carbs?
Energy Balance
 Change in energy stores = energy intake – expenditure
 Assumption- intake and expenditure are
independent variables
 We can change one without changing the other
 USDA- “For most adults a reduction of 50 to 100 calories
per day may prevent gradual weight gain.”
 But- homeostasis- energy regulation involuntary
 Our bodies minimize long-term fluctuations in energy
reserves and maintain a stable weight

Unless the set point is changed
Energy Balance
 Set-point hypothesis
 Energy intake and expenditure are dependent variables
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Physiologically linked
 Energy storage determined biologically- p. 299
 Interaction of genetics and environment
 Any increase in energy expenditure induces hunger and
increase in intake
 Any decrease in intake induces decrease in expenditure
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Slower metabolism or reduced activity
Lean people are more active because more of the energy
they consume is available as energy, less stored as fatdetermined on a cellular or hormonal level