Control of body weight & composition. Nutrition 202 Advanced Nutritional Energetics R. D. Sainz Lecture 14

Transcription

1 Control of body weight & composition Nutrition 202 Advanced Nutritional Energetics R. D. Sainz Lecture 14 1

2 Control of body weight & composition diet physical activity drugs genetics From: Heymsfield,

3 Body fat, % Ideal Moderately high High Very high Males >31 Females >35 Obesity A chronic disease characterized by excessively high body fat in relation to lean body tissue NOT the same as overweight! Incidence: 15 million men, 19 million women in US 3

4 How do doctors define overweight versus obesity? Anyone with a body mass index (a ratio between your height and weight) of 25 or above -- that s someone, for example, who is 5-foot-4 and 145 pounds -- is considered overweight, according to the National Institutes of Health. Anyone with a body mass index of 30 or above -- such as someone who is 5-foot-6 and 186 pounds -- is considered obese. Source: Accessed 03/04/2003. How many Americans are overweight or obese? Thirty-four percent of U.S. adults are considered overweight, and an additional 31 percent are obese. Source: Accessed 03/04/

5 BMI < to to to to 40 > 40 Classification Underweight Normal Overweight Obese Disease risk Moderate Very low Low Moderate High Very high No data < 10% 10 14% 15 19% 20 24% 25 29% > 30% 5

6 No data < 10% 10 14% 15 19% 20 24% 25 29% > 30% No data < 10% 10 14% 15 19% 20 24% 25 29% > 30% 6

7 No data < 10% 10 14% 15 19% 20 24% 25 29% > 30% No data < 10% 10 14% 15 19% 20 24% 25 29% > 30% 7

8 How many deaths are attributed to obesity each year? Three hundred thousand people die each year due to obesity-related causes, making it the second-leading cause of death after smoking. Being overweight or obese increases the risk of hypertension, heart disease, stroke, diabetes and some cancers. Source: Accessed 03/04/2003. Are children affected by the epidemic? Fifteen percent of youngsters ages 6 to 19 and 10 percent of children 2 through 5 are considered seriously overweight. Source: Accessed 03/04/

9 9

10 Why are so many dieters doomed to fail? About 45 percent of women and 25 percent of men are trying to lose weight at any one time, but only one-fifth are using the recommended combination of fewer calories and increased exercise. Source: Accessed 03/04/2003. Diet Energy intake depends upon appetite (black box?) Related to physical activity? Anxiety (some people) carbohydrates dopamine/serotonin signals in brain (reward center) 10

11 11

12 Diet composition: Diet fat quotient CH 2 O, protein oxidation vary with intake Fat oxidation excess energy So: fat in diet food intake (to meet CH 2 O need) ME intake, RE Alcohol uncertain energy value Saris, WHM Physiological aspects of weight cycling. Am. J. Clin. Nutr. 49:

13 From: Lieber,CS Perspectives: do alcohol calories count? Am J Clin Nutr 54:976. From: Lieber,CS Perspectives: do alcohol calories count? Am J Clin Nutr 54:

14 From: Lieber,CS Perspectives: do alcohol calories count? Am J Clin Nutr 54:976. Why? Microsomal ethanol oxidation (no ATP) Increased thermogenesis Increased ATP breakdown Mitochondrial damage uncoupling of oxidation & phosphorylation 14

15 Drugs Fen/phen: d,l-fenfluramine + phentermine d-fenfluramine: s serotonin, s appetite l-fenfluramine: causes drowsiness phentermine: amphetamine Redux: d-fenfluramine ( pulmonary hypertension) Chromium picolinate alters sensitivity to insulin? Ephedrine Sleep 15

16 From: Patel et al., 2006 From: Patel et al.,

17 Exercise 17

18 From: Pavlou, KN, Krey, S, and Stefee, W Exercise as an adjunct to weight loss and maintenance in moderately obese subjects. Am. J. Clin. Nutr. 49:1115. From: Pavlou, KN, Krey, S, and Stefee, W Exercise as an adjunct to weight loss and maintenance in moderately obese subjects. Am. J. Clin. Nutr. 49:

19 Even though they eat the high-fat, high-sugar diet typical of pre-world War II Americans -- meat, potatoes, gravy, eggs, garden vegetables, bread, pies, and cakes -- the Ontario Amish are remarkably fit. Only 4% are obese and only 26% are overweight. From: Levine et al., 2005, Science 307:

20 From: Levine et al., 2005, Science 307:584-6 From: Harris et al., Obesity 14:

21 From: Harris et al., Obesity 14:690-5 From: Harris et al., Obesity 14:

22 Genetics & obesity Pigs: h 2 for backfat 0.50 Humans (probability of obesity) 2 normal parents: 14% 1 normal, 1 obese parent: 40% 2 obese parents: 80% Identical twins are twice as likely to have similar weights as fraternal twins (even when separated and adopted) From: Faith et al.,

23 From: Ravussin, E, Bogardus, C. Relationship of genetics, age, and physical fitness to daily energy expenditure and fuel utilization. Am J Clin Nutr 1989; 49: From: Ravussin, E, Bogardus, C. Relationship of genetics, age, and physical fitness to daily energy expenditure and fuel utilization. Am J Clin Nutr 1989; 49:

24 From: Bouchard, C. and A. Tremblay J. Nutr. 127: 943S-947S. 12 pairs of male twins Energy surplus: 4.18 MJ/d x 6 d/week x 100 d Mean wt gain 8.1 kg (4-13 kg) 5.4 kg fat 2.7 kg protein 63% of excess snergy No difference in DE +10% RMR From: Bouchard, C. and A. Tremblay J. Nutr. 127: 943S-947S. 24

25 12 pairs of male twins Energy surplus: 4.18 MJ/d x 6 d/week x 100 d Mean wt gain 8.1 kg (4-13 kg) 5.4 kg fat 2.7 kg protein 63% of excess snergy No difference in DE +10% RMR From: Bouchard, C. and A. Tremblay J. Nutr. 127: 943S-947S. 7 pairs of young male identical twins Constant intake Energy deficit: Cycle ergometers 2X/d x 9/10 days x 93 days Averaqe deficit 243 MJ Mean wt loss 5.0 kg (-0.8 to -8 kg) All fat Mostly abdominal (from 81 to 52 cm 2 ) 192 MJ loss (78% of deficit) From: Bouchard, C. and A. Tremblay J. Nutr. 127: 943S-947S. 25

26 7 pairs of young male identical twins Constant intake Energy deficit: Cycle ergometers 2X/d x 9/10 days x 93 days Averaqe deficit 243 MJ Mean wt loss 5.0 kg (-0.8 to -8 kg) All fat Mostly abdominal (from 81 to 52 cm 2 ) 192 MJ loss (78% of deficit) HEREDITY IS THE SINGLE MOST IMPORTANT FACTOR AFFECTING ENERGY EXPENDITURE, BODY WEIGHT AND COMPOSITION 26

27 Example: Uncoupling proteins From: Ricquier,

28 From: Herrmann et al., 2003 From: Kim et al.,

29 From: Scarpace et al., 1997 From: Surwit et al.,

30 From: Surwit et al., 1998 From: Surwit et al.,

31 pp From: Kimm et al.,

32 From: Walder et al., 1998 From: Millet et al.,

33 From: Millet et al., 1997 Questions that still nag me about energetics in adult humans: 1. If negative energy balance reduces BMR, how can the original level of BMR be maintained or recovered? 2. Mechanistically, how does the body lower and raise BMR? 3. Do intensity, duration, and timing (morning, before/after eating, evening, etc) affect the number of calories burned? If so, what is the mechanism? 4. What is the best dietary strategy to build lean mass? 5. What metabolic /physiological differences are responsible in the high variability between individuals and families? 6. How can we assess individual metabolism and needs to provide personalized nutritional advice? 33

34 Thank you! 34