Adipose Tissue Fat is metabolically active endocrine tissue Secretes hormones and chemical messengers (adipokines) that travel to other organs and alter organ function and health Leptin Leptin Adiponectin Adiponectin Resistin Resistin Inflammatory molecules (CRP, TNF, etc.) Inflammatory molecules (CRP, TNF, etc.) Estrogens Estrogens
Adipose tissue Subcutaneous fat appears to be benign Central (visceral) fat is potentially more harmful. Releases more “disease causing” adipokines Excessive visceral accumulation can lead to adipokine dysregulation (“lipotoxicity”) Liver (non-alcoholic fatty liver disease) Liver (non-alcoholic fatty liver disease) Pancreas (Type II diabetes) Pancreas (Type II diabetes) Muscle (insulin resistance) Muscle (insulin resistance) Heart (diabetic cardiomyopathy) Heart (diabetic cardiomyopathy)
Waist to Hip ratio (WHR) Apple Shape (android body): Visceral Fat Visceral Fat risk of diabetes, cardiovascular disease stroke, high blood pressure, breast cancer risk of diabetes, cardiovascular disease stroke, high blood pressure, breast cancer Pear shape (gynoid body): Subcutaneous Fat (hips, etc) Subcutaneous Fat (hips, etc) Does not seem to carry same health risks Does not seem to carry same health risks waist hip
Interpretation of WHR Measure girth at smallest abdominal circumference and largest hip circumference >1.0 in men is indicative of android shape >.8 in women in indicative of android shape
Waist Circumference Measure of “intra-abdominal or visceral fat” Measured at the top of the iliac crest Desirable: Men: 40 in (102 cm) Women: 35 in (88 cm) National Heart Lung and Blood Institute and the North American Association for the Study of Obesity, 2001.
Body Mass Index (BMI [kg/m 2 ])
Mortality risk and BMI Flegal, et al. JAMA, 2005;293:1861-1867
Flegal, et al. 2007 JAMA;298(17)2028-2037.
BMI and cause-specific mortality in 900,000 adults: collaborative analysis of 57 prospective studies. (Lancet 2009; 373:1083-96)
Other findings BMI > 30 was strongly associated with heart attack Elevated BMI was strongly associated with strokes, likely due to it’s association with blood pressure Diabetes risk increased significantly with BMI’s > 30
Summary of BMI and Health “Healthiest” BMI’s ranges appear to be as follows: 18.5-25.0 (normal weight) 18.5-25.0 (normal weight) 26-29 (overweight) most studies suggest this range might even be healthier then “normal weight” 26-29 (overweight) most studies suggest this range might even be healthier then “normal weight” <18.5 (underweight) is associated with higher mortalities Some BMI related health risks begin at 30-35 Increased health risks really begin with BMI’s >35
100 # 60 5 20 15
TYPES OF FAT ESSENTIAL FAT Fat in nerves, heart, brain, bone marrow, mammary glands, etc. Not stored fuel 3% in men 12% in women Considered part of LBM STORAGE FAT Adipose tissue (visceral and subcutaneous) Cushions vital organs Superb storage system for extra calories 1 lb = 3,500 kcals
Female: 5’3” Weight: 120# Body Fat: 19% 120 X.19 = 22.8# total fat 120 X.12 = 14.4# essential fat 8.4# of stored fat 8.4 X 3,500 kcals = 29,400 29,400 2,300 = 12.8 days of stored fuel
Body Composition and Health Abdominal (visceral) fat is generally more unhealthy than hip or subcutaneous fat Currently there is no consensus on how total body fat is linked with chronic disease There are no accepted published “healthy” body fat ranges Low body fat does not guarantee “fit” or “healthy” Body composition changes with age More fat in old age is likely beneficial
The Obese Without Cardiometabolic Risk Factor Clustering and the Normal Weight With Cardiometabolic Risk Factor Clustering. Wildman, et al. Arch Intern Med. 2008;168(15):1617-1624. Metabolically Healthy (54%)Metabolically Abnormal (46%) Normal weight OverweightObese Normal weight OverweightObese Percent (%) of Adult Americans 26.4220.127.116.11.020.9 # of Adult Americans 52,982,37835,923,65819,46701016,255,95734,117,44041,944,382
Identification and Characterization of Metabolically Benign Obesity in Humans. Stefan, et al. Arch Intern Med. 2008;168(15)1609-1616.
What is a healthy lifestyle Healthy diet Regular physical activity Avoiding harmful substances and risky behaviors (tobacco, substance abuse, seat belts, car seats, promiscuity, high risk activities) Adequate rest Appropriate use of health care (screenings, immunizations, prevention, following competent medical advice)
The Elusive “Moderation” Extreme dieting Fad diets Too many rules/restrictions Deprivation vs. self control Over exercise Total “junk food” diet Follow no guidelines Totally sedentary Overly indulgent Cynicism Healthy eating and exercise (variety, moderation) Gradual, doable changes in lifestyle
“Current” thinking in defining successful weight loss A permanent decrease in 5-10% of initial body weight 200 *.10 = 20 pounds 150 *.10 = 15 pounds A reduction of 10% body weight often lowers blood pressure, improves blood glucose control, and lowers cholesterol Following successful maintenance of 10% weight loss further weight loss can be attempted if necessary
Realistic goals for weight loss A caloric deficit of 500 to 1000 kcal a day would result in 1-2 pounds of weight loss per week Combination of dietary and physical activity is recommended to achieve the calorie deficit More rapid weight loss is not recommended without competent medical supervision
To Be Healthy… Be Realistic Be Sensible Be Patient Be Consistent