Metabolic and Clinical Aspects of Weight Management FSHN 420

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Is a calorie a calorie?
or are all foods created equal?
Donald K. Layman Department of Food Science
Human Nutrition University of Illinois
Urbana-Champaign
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Obesity 1 public health problem in U.S.
Popular diets
Atkins Diet Revolution Protein Power South
Beach The Zone
Weight Watchers USDA Food Guide
Pyramid Pritikin Ornish
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The Great Diet Debate
What is the ideal balance of macronutrients?
fats carbohydrates protein
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The Environment of Obesity
Physical activity
availability
lifestyle
Food
Stress
taste
cost
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U.S. Nutrition Policy
1970 - 2000 The Era of Heart Disease
fat is the root of all evil
Currently, nutrition practice is driven by public
opinion
The Low Carb Craze
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Dietary Guidelines for Americans

• consume a variety of foods
• control calorie intake to manage body weight
• be physically active
• increase daily intake of fruits, vegetables,
• whole grains, and low fat dairy
• choose fats wisely
• choose carbohydrates wisely
• choose and prepare foods with little salts
• drink alcohol in moderation
• keep food safe to eat

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USDA Food Guide Pyramid
fats
milk cheese
meat fish, eggs
2-3 servings
2-3 servings
vegetables
fruits
3-5 servings
2-4 servings
bread, cereal, rice pasta 6-11 servings
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The Myths of Macronutrients
fats the root of all evil
carbohydrates the more the merrier
protein everybody eats too much
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Changes in U.S. diet (1970 2000)

• red meat (25)
• dairy (30)
• eggs (40)

• grains (decreased vegetables)
• fruit juices (decreased fruits)
• sodas
• snack foods (refined carbohydrates)

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Impact on the U.S. Diet

• cholesterol
• (from 650 mg/d to
• total fat
• (from 40 of calories to 33)
• saturated fat
• (from 17 of calories to 12)

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Impact on the U.S. Diet
increased total calories!!!
decreased intakes of iron, zinc, calcium,
B-vitamins, fiber and vitamin A
average protein intake women 68
grams/day men 90 grams/day
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Dietary Reference Intakes (DRI)
RDA
UL
Risk of Adverse Affects
Risk of Inadequacy
safe
deficiency
toxicity
metabolic balance
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Personal choices metabolic outcomes
Male athlete, 22 y.o., 180 lbs, 7 body fat, 3700
kcal/d
15 protein 138 g/d 55 CHO 508 g/d 30 fat
123 g/d
Female CPA, 57 y.o., 180 lbs, 39 fat, 2100 kcal/d
15 protein 74 g/d 55 CHO 289 g/d 30
fat 70 g/d
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The right diet for the right person how do we
chose?
U.S. Population ( 300 million)
blood lipid profiles
normal
27 m
46 m
hypercholesterolemia
dyslipidemia
Syndrome X
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Syndrome X (metabolic syndrome)
In 1988, Dr. Reaven reported that individuals
with impaired glucose tolerance and compensatory
hyperinsulinemia had increased risk for Coronary
Heart Disease (CHD).
stability of blood sugar
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Weight loss diets (at 1700 kcal)
RDA
Upper Limit

250
170
350 g ??
CHO 130 g
70
120
protein 65
250 g ??
USDA Food Guide Pyramid 250/70 3.5
Moderate Carb/moderate protein diet 170/120 1.5
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Findings with moderate protein diets

• weight loss
• loss of body fat
• sparing of muscle protein
• triglycerides
• HDL
• stability of blood sugar
• Layman et al. J. Nutrition 133411, 2003

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Moderate Protein Diet (10 weeks)
Weight loss CHO 15.3 lbs Prot. 16.6 lbs
fat as of loss CHO 69 Prot. 75
Layman J. Nutr. 133411, 2003
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Is a calorie a calorie?
Yes, but

• thermogenesis

• satiety

• biological function

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Protein needs vs. requirements
Protein structures RDA 0.8 g/kg
Metabolic roles 60 to 70 g/day
Physical activity 10 g/hour of activity
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Carbohydrate quantity and quality

• glycemic index and glycemic load

• fiber source, type, form

• fructose

• Net Carbs

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A calorie is a calorie

• Weight management is determined by
• portion control
• physical activity

but each macronutrient has different
biological functions
What is the nutrient tolerance for each
individual?
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Dietary Guidelines for Americans

• consume a variety of foods
• control calorie intake to manage body weight
• be physically active
• increase daily intake of fruits, vegetables,
• whole grains, and low fat dairy
• choose fats wisely
• choose carbohydrates wisely
• choose and prepare foods with little salts
• drink alcohol in moderation
• keep food safe to eat

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Personal choices
lifestyle
Physical activity
Food intake
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Personal choices metabolic outcomes
Male athlete, 22 y.o., 180 lbs, 7 body fat, 3700
kcal/d
protein 17 161 g/d additional energy
3056 kcal fat 26 106 g CHO 57
527 g
Female CPA, 57 y.o., 180 lbs, 39 fat, 1700 kcal/d
protein 31 131 g/d additional energy
1176 kcal fat 30 57 g CHO
39 166 g
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The Future
Individualization of diets the right diet for
the right person
Food quality not quantity