Obesity and Energy Balance

1. Obesity andEnergy Balance Advanced Healing Methods GCU Holistic Health Fall 2009

2. 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 • 1993-1997: 3800 calories • 90% of the 500 calories from carbs • The rise in obesity also coincides with increasing exercise

3. 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.”

4. 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 • 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 • 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”

5. 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 • But not necessarily caused by it • Two possibilities • Overeating and inactivity cause obesity • “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

6. 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

7. 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 • 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-carbthan 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

8. The Low-Fat Diet • Low-fat, high-carb diets recommended for weight loss • Evidence • The density of fat calsfools people into eating too many • 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

9. 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 • 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

10. 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.”

11. 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”

12. 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 • 5100 cals/day, 80% carbs, 9% fat • Overfeeding studies- 10,000 calories of mostly carbs a day, but hunger late in the day

13. 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 • Cream, butter, olive oil, eggs, cheese, meat • 2 lbs weight loss per week, no chronic hunger or fatigue

14. 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

15. 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, 13-28 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”

16. 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 all- weight 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

17. 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 semi-starvation diet • 50X less effective for weight loss

18. 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 • 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 • Diabetic ketoacidosis- pathological- 200 mg/dl

19. Reducing Diets • V. Stefansson- early 20th century • Lived with the Inuit for 10 years eating only meat • 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

20. 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 • 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

21. Reducing Diets • Deficiency diseases • Studies all done with high-carb diets low in meat and dairy- p. 321 • Meat contains all essential amino acids • 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?

22. Reducing Diets • Deficiencies • B vitamins depleted by carbsin diet • Vitamin C also • 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” • 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 reabsorptionof 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?

23. 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

24. Energy Balance • Set-point hypothesis • Energy intake and expenditure are dependent variables • 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 • Slower metabolism or reduced activity • Lean people are more active because more of the energy they consume is available as energy, less stored as fat- determined on a cellular or hormonal level