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Research on Nutritional Research on Nutritional Contributors to ObesityContributors to Obesity
Neal D. Barnard, M.D.
Physicians Committee for Responsible Medicine
5100 Wisconsin Avenue NW, Suite 400
Washington, DC 20016
Obesity in the U.S. and JapanObesity in the U.S. and JapanBMI BMI ≥≥ 30 30
Yoshiike N. Obes Rev 2002;3:183-90. Flegal KM. Int J Obesity 1998;22:39-47.
United States
Japan
%
0
5
10
15
20
25
30
1960 1971- 1976- 1988- 1999- 1974 1980 1994 2000
Obesity in the U.S. and JapanObesity in the U.S. and JapanBMI BMI ≥≥ 30 30
Yoshiike N. Obes Rev 2002;3:183-90. Flegal KM. Int J Obesity 1998;22:39-47.
United States
Japan
%
0
5
10
15
20
25
30
1960 1971- 1976- 1988- 1999- 1974 1980 1994 2000
Overweight in U.S. and JapanOverweight in U.S. and Japan
Yoshiike N. Obes Rev 2002;3:183-90. Flegal KM. Int J Obesity 1998;22:39-47.
39.1 39.4
14.5
20.5
0
10
20
30
40
50
c.1980 c. 1990
BMI 25–29.9 kg/m2
U.S.
Japan
% %
%
%
%
Overweight and Obesity in JapanOverweight and Obesity in Japan
Yoshiike N. Obes Rev 2002;3:183-90. Yoshiike N. Asia Pac J Clin Nutr 2002;11(Suppl 8):S727-31.
24.5
20.5
14.5
2.32.010.8
0
10
20
30
1976-80 1991-95 2000
BMI 25-29.9
BMI ≥ 30
%
%
%
%% %
%
Prevalence in MenPrevalence in Men
Falling Carbohydrate Intake in Japan
Murata M. Am J Clin Nutr 2000;72(suppl):1379S-83S.
Carbohydrate (grams/day)
250
280
310
340
370
400
430
1955 1965 1975 1985 1994
Rising Fat Intake in Japan
Murata M. Am J Clin Nutr 2000;72(suppl):1379S-83S.
Fat (grams/day)
0
10
20
30
40
50
60
1955 1965 1975 1985 1994
Dietary Patterns and ObesityDietary Patterns and Obesity
Asia
Grain-Centered Diet
Obesity Is Rare
U.S., Prior to 1980
Meat-Centered Diet
Obesity Is Common
U.S. After 1980
Meat-Centered Diet + Extra
Calories
Obesity Is an Epidemic
Differential Roles for CarbohydrateDifferential Roles for Carbohydrate
Asia
Carbohydrate-rich foods are staples:
Rice
Starchy vegetables
Noodles
U.S.
Carbohydrate-rich foods are vehicles for dietary fat:
Toast and butter
Potatoes and gravy
Spaghetti and meat
Pizza and cheese
A Randomized, Controlled Study of A Randomized, Controlled Study of the Effect of a Low-Fat, Vegan Diet the Effect of a Low-Fat, Vegan Diet on Body Weight and Metabolism in on Body Weight and Metabolism in
Postmenopausal WomenPostmenopausal Women
Neal D. Barnard, M.D., Anthony R. Scialli, M.D.,Neal D. Barnard, M.D., Anthony R. Scialli, M.D.,Gabrielle Turner-McGrievy, M.S., R.D.,Gabrielle Turner-McGrievy, M.S., R.D.,Amy J. Lanou, Ph.D., Jolie Glass, M.S.Amy J. Lanou, Ph.D., Jolie Glass, M.S.
Funded by the Cancer Project of the Physicians Committee for Responsible MedicineFunded by the Cancer Project of the Physicians Committee for Responsible Medicine
MethodsMethods
• 59 overweight (BMI 26-44 kg/m59 overweight (BMI 26-44 kg/m22) ) postmenopausal womenpostmenopausal women
• Randomly assigned to a low-fat vegan or Randomly assigned to a low-fat vegan or control dietcontrol diet
• Exercise levels held constantExercise levels held constant
• Data collected at baseline and 14 weeksData collected at baseline and 14 weeks
DietsDiets
Low-Fat, Vegan DietLow-Fat, Vegan Diet• Grains, vegetables, legumes, and fruitsGrains, vegetables, legumes, and fruits• No limit on energy intake or portion sizesNo limit on energy intake or portion sizes• Excluded animal products, oils, high-fat plant foodsExcluded animal products, oils, high-fat plant foods• ~10% of energy from fat, 15% from protein, and 75% from ~10% of energy from fat, 15% from protein, and 75% from
carbohydratescarbohydrates
Control DietControl Diet• NCEP Step II guidelinesNCEP Step II guidelines• No limit on energy intakeNo limit on energy intake• Meat intake Meat intake << 6 ounces/day and fat grams 6 ounces/day and fat grams << 60 per day 60 per day• Total fat limited to 30% of energyTotal fat limited to 30% of energy• ~15% of energy from protein and > 55% from carbohydrates~15% of energy from protein and > 55% from carbohydrates
Nutrient Intake Nutrient Intake
0
50
100
150
200
250
300
Protein* Carbohydrates** Total Fat** Total Fiber**
Gra
ms Baseline-Vegan
14 Weeks-Vegan
Baseline-Control
14 Weeks-Control
* P = 0.05* P = 0.05
** P < 0.05** P < 0.05
For comparison of For comparison of low-fat vegan versus low-fat vegan versus control diet changes control diet changes (baseline to 14 (baseline to 14 weeks).weeks).
Fiber Reduces Calorie IntakeFiber Reduces Calorie Intake
Every 14 grams of fiber in the daily diet
reduces energy intake by approximately 10%.
Vegan Diet vs. NCEP Step II DietVegan Diet vs. NCEP Step II Diet
Energy (kcal)
1429
1784
1396
1762
1300
1500
1700
0 14
Weeks
Step II Diet (N=30)
Vegan Diet (N=29)
Vegan Diet vs. NCEP Step II DietVegan Diet vs. NCEP Step II Diet
Fat (grams)
18
32
59
62
10
20
30
40
50
60
0 14
Weeks
Step II Diet (N=30)
Vegan Diet (N=29)
Vegan Diet vs. NCEP Step II DietVegan Diet vs. NCEP Step II Diet
Carbohydrate (grams)
230
272
222
235
220
230
240
250
260
270
280
0 14
Weeks
Step II Diet (N=30)
Vegan Diet (N=29)
Changes in Body CompositionChanges in Body Compositionand Metabolism and Metabolism
-8
-6
-4
-2
0
2
4
6
Wei
ght
(kg)
**
BM
I (k
g/m
2)**
Bod
y F
at (
%)
Lea
n M
ass
(kg)
Wai
st (
in)*
*
Hip
(in
)**
RM
R/L
BM
(kca
l/d/
kg)
TE
F (
kca
l/3h
r)
Low-Fat Vegan(n=29)
Control (n=30)
** P < 0.05** P < 0.05
For comparison of For comparison of low-fat vegan versus low-fat vegan versus control diet changes control diet changes (baseline to 14 (baseline to 14 weeks).weeks).
Insulin SensitivityInsulin Sensitivity
We found an average 24% increase in insulin sensitivity in the vegan
group, with no significant change in this
variable in the Step II group.
Lanou A, Scialli AR, Turner-McGrievy G, Glass J. Unpublished Data. 2003.
Fat ContentFat Content(Percentage of Calories from Fat)(Percentage of Calories from Fat)
• Leanest beef 29%
• Skinless chicken breast 23%
• Sea trout 32%
• White tuna 16%
• Broccoli 8%
• Beans 4%
• Rice 1–5%
• Potato 1%
Casomorphins
Opiates that form as casein (milk protein) is digested.
Casomorphins
From ß-casein:
ß-casomorphin-7 Try-Pro-Phe-Pro-Gly-Pro-Ile
ß-casomorphin 5 (bovine) Tyr-Pro-Phe-Pro-Gly
ß-casomorphin 5 (human) Tyr-Pro-Phe-Val-Glu
Morphiceptin Tyr-Pro-Phe-Pro-NH2
From as1-casein:a-Casein exorphin Arg-Gly-Phe-Gin-Asn-Ala
Shah NP. Br J Nutr 2000;84(suppl 1):S3-S10.Teschemacher H. J Dairy Res 1986;53:135-8.
Super-Sizing, 1977–98 (U.S.)
Nielsen SJ. JAMA 2003;289:450-3.
Portion Sizes in Ounces
0
2
4
6
8
10
12
14
16
18
20
1977-19781989-19911994-1996
Soft Fruit Ham- Cheese- Drinks Drinks burgers burgers
U.S. Cheese Intake Has Doubled
0
5
10
15
20
25
30
35
1975 1999
Wendy’s “Cheddar Lover’s Bacon Cheeseburger”
promotion sold:
• 2.25 million pounds of cheese
• 380 tons of fat
• 1.2 tons of pure cholesterol
USDA Report to Congress on the Dairy Promotion Programs, 2000
The U.S. Government at WorkThe U.S. Government at Work
• Wendy’s “Cheddar Lover’s Bacon Cheeseburger”
• Subway’s “Chicken Cordon Bleu,” “Honey Pepper Melt”
• Pizza Hut’s “Ultimate Cheese Pizza”
• Burger King, Taco Bell
USDA Report to Congress on the Dairy Promotion Programs, 2000
The U.S. Government at WorkThe U.S. Government at Work
Dick Cooper, Vice President of Cheese Marketing, Dairy Management, Inc., at the “Cheese Forum,” December 5, 2000. USDA Report to Congress on the Dairy Promotion Programs, 2000
BMI of Meat-Eaters and Vegetarians
Appleby PN. Int J Obes 1998;22:454-60.
Oxford Vegetarian Study (age-adjusted means)
Male Meat-Eaters 23.2 kg/m2
Male Non-Meat-Eaters 22.1 kg/m2
Female Meat-Eaters 22.3 kg/m2
Female Non-Meat-Eaters 21.3 kg/m2
All participants were non-smokers.N = 2,445 meat-eaters, 2,287 non-meat-eaters
Loma Linda Study
Haddad. Am J Clin Nutr 1999;70(suppl):586S-93S.
Mean Age (years) 33.5 36.0Mean BMI (kg/m2) 25.5 20.5
Non-Vegetarians (20) Vegans (25)
Bread (servings) 10.9 11.7Vegetables (servings) 1.4 3.3Fruit (servings) 2.6 5.6Legumes (1/2 cup servings) 0.3 1.2Nuts and seeds (ounces) 0.2 0.9Meat (ounces) 6.3 0Milk (cups) 0.9 0
Diet Characteristics
Loma Linda Study
Haddad. Am J Clin Nutr 1999;70(suppl):586S-93S.
0
2
4
6
8
10
12
Bread Vegetables Fruit Legumes Nuts & Meat Milk (servings) (servings) (servings) (1/2 cup Seeds (ounces) (ounces)
servings) (ounces)
Non-Vegetarians (20) Mean Age — 33.5 yearsMean BMI — 25.5 kg/m2
Vegans (25)Mean Age — 36.0
Mean BMI — 20.5 kg/m2
=
=
Dangers of Low-Carbohydrate, High-Dangers of Low-Carbohydrate, High-Protein DietsProtein Diets
Low-Carbohydrate, High-Protein Low-Carbohydrate, High-Protein (“Atkins”) Diet(“Atkins”) Diet
Induction Phase=20 grams carbohydrate
Excluded:Fruit
Starchy vegetablesLegumes
GrainsMilk
AlcoholCaffeine
Permitted:MeatsEggs
Cheese (3-4 oz.)Nonstarchy vegetables
Salad vegetables
(3 cups maximum for all vegetables)
Low-Carbohydrate, High-Protein Low-Carbohydrate, High-Protein (“Atkins”) Diet(“Atkins”) Diet
Transition Phases (“Ongoing Weight Loss,” “Pre-Maintenance”)Slowly increase carbohydrates until weight loss stalls.
Maintenance PhaseMaintain carbohydrate restriction for life.
Nutrient Analysis of Atkins Nutrient Analysis of Atkins Sample MenusSample Menus
Nutrient intakes are based on Dr. Atkins’ New Diet Revolution (M. Evans & Co., 1999), using Nutritionist V., Version 2.0, for Windows 98 (First DataBank, Inc., Hearst Corporation, San Bruno, CA).
Atkins Atkins Induction Maintenance
Energy, kcal 1759 2173Protein, g (% energy) 143 (33%) 135 (25%)Carbohydrate, g (% energy) 15 (3%) 116 (22%)Fat, g (% energy) 125 (64%) 110 (45%)Saturated fat, g 42 38Cholesterol, mg 886 834Fiber, g 2 18
Initial Weight Loss Initial Weight Loss on Low-Carbohydrate Dietson Low-Carbohydrate Diets
Water loss:
1 pound of glycogen holds 3 pounds of water
Fiber (grams)Fiber (grams)53
25
2
18
Atkins Diet nutrient intakes are based on Dr. Atkins’ New Diet Revolution (M. Evans & Co., 1999), using Nutritionist V., Version 2.0, for Windows 98 (First DataBank, Inc., Hearst Corporation, San Bruno, CA).
Low-Fat Pyramid Atkins Atkins Vegan Induction Maintenance
Saturated Fat (grams)Saturated Fat (grams) Cholesterol (milligrams)Cholesterol (milligrams)
= Low-Fat Vegan = Pyramid = Atkins Maintenance
4
24
38
0
235
834
Protein (grams)Protein (grams)
66
93
143135
Atkins Diet nutrient intakes are based on Dr. Atkins’ New Diet Revolution (M. Evans & Co., 1999), using Nutritionist V., Version 2.0, for Windows 98 (First DataBank, Inc., Hearst Corporation, San Bruno, CA).
Low-Fat Pyramid Atkins Atkins Vegan Induction Maintenance
Effects on CholesterolEffects on CholesterolLCHP (“Atkins”) Diets Plus ExerciseLCHP (“Atkins”) Diets Plus Exercise
*Randomized controlled trials and crossover trialsBravata DM. JAMA 2003;289:1837-50.
Stanford University review, 200394 intervention trials
≤ 60 g CHO/d: No effects on TC, LDL, HDL
> 60 g CHO/d: All studies: TC ↓ 8.1 ± 1.4 mg/dl, no other effects Controlled* studies: no effect on lipids
Most studies were confounded by exercise.Most studies did not isolate effects of weight changes on lipids.
LCHP Diets and Serum CholesterolLCHP Diets and Serum Cholesterol
Serum Cholesterol
Saturated Fat
Dietary Cholesterol
Serum Cholesterol
Weight Loss
As Weight Falls, So Does CholesterolAs Weight Falls, So Does Cholesterol
Conversion forumla: Cholesterol in mg/dl x 0.02586 = mmol/LDattilo AM, Kris-Etherton PM. Am J Clin Nutr 1992;56:320-8.
Meta-analysis, Pennsylvania State University
1 lb weight TC 1 mg/dl (US units) LDL 0.4 mg/dl
1 kg weight TC 0.05 mmol/L (SI units) LDL 0.02 mmol/L
The higher the initial cholesterol level, the greater the cholesterol drop during weight loss.
Protein and Loss of Kidney Protein and Loss of Kidney FunctionFunction
Harvard Nurses’ Health Study:
Among women with mild renal insufficiency (GFR 55 to < 80 mL/min per 1.73 m2) followed for 11 years:
Every 10 g non-dairy animal protein → 1.21 mL/min per
1.73 m2 drop in GFR
Atkins Maintenance Diet suggested menu: 135 g protein per day
GFR = Glomerular filtration rate
Knight EL Ann Intern Med 2003;138:460-7.
Prevalence of Decreased Kidney FunctionPrevalence of Decreased Kidney Function
GFR = Glomerular filtration rate, mL/min per 1.73 m2
Coresh J. Am J Kidney Dis 2003;41:1-12.
Mild (GFR 60-89) Moderate (GFR 30-59)
Total population 31.2% (0.8) 4.3% (0.2)
20-39 years 13.7% (0.9) 0.21% (0.07)
40-59 years 42.4% (1.1) 1.8% (0.3)
60-69 years 53.8% (1.8) 7.1% (0.9)
70+ years 48.5% (1.1) 24.6% (1.1)
Prevalence of Decreased Kidney FunctionPrevalence of Decreased Kidney Function
GFR = Glomerular filtration rate, mL/min per 1.73 m2
Coresh J. Am J Kidney Dis 2003;41:1-12.
Mild (GFR 60-89) Moderate (GFR 30-59)
Total population 31.2% (0.8) 4.3% (0.2)
20-39 years 13.7% (0.9) 0.21% (0.07)
40-59 years 42.4% (1.1) 1.8% (0.3)
60-69 years 53.8% (1.8) 7.1% (0.9)
70+ years 48.5% (1.1) 24.6% (1.1)
With diabetes 40.4% (1.9) 14.2% (1.3)
Prevalence of Decreased Kidney FunctionPrevalence of Decreased Kidney Function
GFR = Glomerular filtration rate, mL/min per 1.73 m2
Coresh J. Am J Kidney Dis 2003;41:1-12.
Mild (GFR 60-89) Moderate (GFR 30-59)
Total population 31.2% (0.8) 4.3% (0.2)
20-39 years 13.7% (0.9) 0.21% (0.07)
40-59 years 42.4% (1.1) 1.8% (0.3)
60-69 years 53.8% (1.8) 7.1% (0.9)
70+ years 48.5% (1.1) 24.6% (1.1)
With diabetes 40.4% (1.9) 14.2% (1.3)
Hypertension, no meds 43.2% (1.5) 7.9% (0.7)
Hypertension, on meds 46.0% (1.9) 17.5% (0.9)
Most studies of high-protein diets:
Bravata DM. JAMA 2003;289:1837-50.
• Do not report effects on kidney function
• Do not track long-term effects
Calcium LossesVia Kidney (milligrams/day)
160
258 248
Regular Diet
Atkins Induction
Atkins Maintenance
Reddy ST. Am J Kidney Dis 2002;40:265-74.
Most studies of high-protein diets do not track:
Bravata DM. JAMA 2003;289:1837-50.
• calcium losses
• bone density
•long-term fracture risk
Meat Eating and Colon Cancer
1. Giovannucci E. Cancer Research 1994;54:2390-7. 2. Willett WC. N Engl J Med 1990;323:1664-72.
Risk of Colon Cancer from Eating Beef, Pork, or Lamb
Rarely or Never
≥ 5/wk, Men1
Daily, Women2
1.0
3.6
2.5
Studies of high-protein diets have been too brief to assess colon
cancer risk.
Fat and Alzheimer’s DiseaseFat and Alzheimer’s DiseaseChicago Health and Aging Project
815 healthy individuals, = 65 years old
3.9 year follow-up
Saturated fat: Highest quintile:Lowest quintile:
25.1 g/day
13.0 g/day
Risk 2.2 (CI, 1.1-4.7)
Rush-Presbyterian/St. Luke’s Medical CenterMorris MC. Arch Neurol 2003;60:194-200.
Fat and Alzheimer’s DiseaseFat and Alzheimer’s DiseaseChicago Health and Aging Project
815 healthy individuals, = 65 years old
3.9 year follow-up
Saturated fat: Highest quintile:Lowest quintile:
25.1 g/day
13.0 g/day
Risk 2.2 (CI, 1.1-4.7)
Trans fat: Highest quintile:Lowest quintile:
2.3-4.8 g/day
1.8 g/day
Risk 1.8-2.9*
n-6 fats: Highest quintile:Lowest quintile:
14.5 g/day
7.4 g/day
Risk 0.3
(CI, 0.1-0.9)
Rush-Presbyterian/St. Luke’s Medical CenterMorris MC. Arch Neurol 2003;60:194-200.*Significant for 2nd and 3rd quintiles only
Three Different ApproachesThree Different Approaches
Sugar Fruits Beans Grains Vegetables Dairy Eggs Meat Fats
Sugar Fruits Beans Grains Vegetables Dairy
Dairy Eggs Meat Fats
Atkins DietAtkins Diet
Vegan DietVegan Diet
Low-Calorie DietLow-Calorie Diet
0
19
0
5
10
15
20
25
0 10 20 30
Weight Loss: 1 lb/week
1. Barnard ND, in press. 2. Wadden TA. Ann Int Med 1993;119:688-93. 3. Westman EC. Am J Med 2002;113:30-6.
= Vegan diet, no exercise (14 weeks)1
= 1200-calorie diet (21 weeks)2
= Atkins Diet plus exercise, supplements
(26 weeks)3
0
20
0
5
10
15
20
25
0 10 20 30
0
13
0
5
10
15
20
25
0 10 20 30Weeks
Poun
ds L
ost
Weight Loss per Week (pounds)
0.8
0.9 0.9
0
0.5
1
1. Westman EC. Am J Med 2002;113:30-6; 2. Wadden TA. Ann Int Med 1993;119:688-93; 3. Barnard ND, in press.
Vegan (14 weeks)1
1200-calorie (21 weeks)2
Atkins + exercise (26 weeks)3
Long-Term Weight Loss
1. Westman EC. Am J Med 2002;113:30-6.2. Ornish D. JAMA 1998;280:2001-7.
= Vegetarian diet plus exercise2
= Atkins Diet plus exercise,
supplements1
0
5
10
15
20
25
0 1 2 3 4 50
5
10
15
20
25
0 1 2 3 4 5
The Latest Industry MythThe Latest Industry Myth“Dairy products promote weight loss.”
Evidence based solely on mouse studies or experiments using calorie-restricted diets.
Randomized trials adding dairy products to normal diets either have no effect on weight or cause weight gain.
Non-fat milk derives 55% of calories from sugar (lactose.)
Typical cheeses derive approximately 70% of calories from fat, mostly saturated fat.
The New FourFood Groups
• Grains (rice, bread, pasta, corn, oatmeal, etc.)
• Legumes (beans, peas, lentils)
• Vegetables (carrots, broccoli, spinach, squash, etc.)
• Fruits (apples, bananas, pears, cherries, etc.)
Physicians Committee for Physicians Committee for Responsible MedicineResponsible Medicine
Neal D. Barnard, M.D.
5100 Wisconsin Avenue NW, Suite 400
Washington, DC 20016
202-686-2210
pcrm@pcrm.org