Amino group needs to be excreted

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Outline for today

• Continuing our overview of nutrition
• What is a healthy diet?
• Hunger/satiety
• Guidelines for healthy diets
• Nutrient density
• Food pyramid/dietary guidelines/RDAs etc.
• Food labels

For next time, calculate your BMI
Class web page http//chemistry.ucsc.edu/Faculty
/Fink/80A-2004/2004index.htm
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Announcements

• Please register your response pad (the clicker,
  TV-remote-like thing) on the web ASAP
• You can use the on-line diet analysis programs
  from McGraw Hill http//www.mhhe.com/catalogs/sem
  /nutrition/nutrition_analysis/
• Also has a BMI calculator
• First issue well discuss is weight control
• Fasting
• Low carb and other diets
• Obesity
• Anorexia etc.
• READ chapt. 10 for this

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What Is A Healthy Diet?

• One with
• Variety
• Balance
• Moderation
• Do you eat a healthy diet? (CPS questions)

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The American Diet

• In general the US diet has
• Too much fat, salt, alcohol and simple sugars
  (not enough fiber)
• Potentially insufficient
• iron, calcium, zinc
• Vitamin A, C, some of the B vitamins
• Fiber (predominantly insoluble carbohydrates)

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Why variety, moderation and Balance?
Variety ensures that you will get all the
necessary nutrients. Most individual foods are
incomplete as far as our needs are concerned. In
addition, there are many compounds in foods that
are beneficial for our health (phytochemicals) Ba
lance means consuming foods from the five major
food groups - this is the basis of the "food
pyramid" idea. Together, these different classes
of foods will provide all the necessary nutrients
you need. Moderation - not good to have
excessive amounts of any one food in your diet.
One reason is that for several essential
nutrients, too much is not good for you, e. g.
Vitamin A or iron. In general, the nutrients that
have the smallest difference in concentration
between optimal and toxic effects are Vitamins A
and D, iron, copper, calcium, and in fact, most
minerals (if you take supplements check these
out).
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The general consensus among nutrition experts is
that your diet should provide 55-65 of Cals
from carbohydrates, 10-15 from protein and
from fat. You can use your diet analysis to
answer this question for your own diet
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Desire to eat

• Hunger
• Physical biological drive
• Appetite
• Psychological drive
• Controlled by many hormones, blood sugar level
  etc.

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Satiety

• Regulated by the hypothalamus
• Controlled by
• Meal size and composition
• Hormones
• Probably blood sugar level

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Influences of Food Choices
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All Foods Are Not Created Equal

• Nutrient density
• Comparison of vitamin and mineral content to
  number of kcals
• Empty calories
• Provides kcals and few to no other nutrients
• Energy density
• Comparison of the kcal content to the weight of
  the food
• Low-energy-density foods in a meal contributes to
  satiety
• Foods with more water and dietary fiber
• Most foods have different composition to our
  bodies

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Comparison of Nutrient Density soda vs. NF milk

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Table 2.3
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Desirable State of Nutritional Health

• Intake meets bodys needs
• Body has a small surplus, except for Cals

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The Dietary Guidelines

• The general consensus among nutrition experts is
  that your diet should provide 55-65 of Cals from
  carbohydrates, 10-15 from protein and fat.
• The US Daily Food Guide is divided into five
  groupsBread, cereals, rice pastaVegetablesFr
  uitsMeat, poultry, fish, dry beans, eggs and
  nutrientsMilk, yogurt and cheese

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The Food Guide Pyramid

• To translate nutritional science into practical
  terms
• To help people meet the nutritional needs for
  carbohydrate, protein, fat, vitamins, minerals
• Provides a foundation to eating

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The Food Guide Pyramid

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Other Pyramids

• Mayo Clinics Healthy Weight Pyramid
• DASH Pyramid
• Ethnic Pyramids
• Dr. Walter Willetts Healthy Eating Pyramid
• The America Institute for Cancer Researchs Plate
  (vs. Pyramid)
• All with an emphasis on fruits, vegetables, and
  whole grains

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Guidelines for a healthy diet

• Choose low-fat options
• Include plant proteins several times a week
• Include dark green vegetable every day
• Include a vitamin C rich food every day
• Choose whole-grain products
• Include plant oils daily

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Benefits of the different food groups
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Table 2.8b
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Alternatives for a healthy diet
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Aim for Fitness

• Healthy weight
• BMI
• Be physically active each day
• 30 minutes a day, most days out of the week

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BMI Body Mass Index

• BMI body weight in kg/(height)2 in meters
• weight in pounds x 703.1/(height)2 in
  inches
• If your height is 60 inches and your weight is
  128 lb your BMI is 25
• 63 141
• 65 150
• 68 164
• 70 174
• 73 189
• Roughly, 6-7 lbs 1 BMI unit
• BMI of 25-30 overweight
• BMI 30 obese

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Daily Reference Intake (DRI) (or RDAs)

• How much do we need of each nutrient for optimal
  health?
• In the US a panel of nutrition experts convened
  by the government every few years DRIs are
  updated/modified as new scientific information
  becomes available.
• A few important points to note the panel are
  leading nutritional experts drawn mostly from
  universities the RDA values are based on the
  best scientific data available Note that they
  are not minimum values, nor optimal values they
  are safe and adequate intakes a given
  individual's requirements may be significantly
  lower than the RDA value they are for healthy
  people

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Standards Under the DRI

Est. Ave. Requirements (EARs)

RDAs Daily Ref. Intake
Adequate Intake (AIs)

Tolerable Upper Intake Levels (ULs)
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How much do we need ?

• Our bodies have a buffering effect e. g. if
  you don't get enough of an essential amino acid
  today, but have been getting enough in the past,
  and in the future continue to get the required
  amount, then this will have minimal effects
• RDAs based on minimum amount necessary to
  prevent symptoms of the deficiency disease, as
  well as nutrient balance (intakeoutput).
• For a given population group e. g. females
  19-24, bell-shaped distribution of the daily
  requirement. Typically the RDA is set at 2
  standard deviations above the mean (which means
  that it includes 98.5 of the population). Note
  that a value of half the RDA would be
  insufficient for a large number of people.
• Remember the R stands for recommended not
  required.