Wednesday March 3, 1999
Announcements: If you are not going to be in class on Friday the notes can be found on the class website in the syllabus or you can go to Yournotes.com.

Lecture notes:

Nutrients in the diet

Carbohydrates - used for: energy
conversion to fats and proteins
parts of some body cells and proteins

Proteins - structure
function
metabolism
energy

Two types of amino acids: essential- the body can't make, they must come from the diet.
Non-essential- the body can make or convert

Food sources of proteins: complete protein contains all the essential amino acids in proportions needed to
make human proteins (animal protein and almost all animal products contain
complete protein, meat, fish)

Incomplete protein has one or more missing amino acids (grains, legumes, gelatin)

Lipids - there is 1 essential fatty acid in adults. We need a small amount of one type of polyunsaturated fat per day.

Functions: store energy
membranes
some hormones

Water- every chemical reaction in the body must take place in water. It is also important in temperature regulation.
* about 25% of the population is dehydrated at any time.

Vitamins - co-enzymes
- parts of important molecules
- Vitamins are needed in small amounts. "Megadoses" can be harmful.
- hormones

Minerals - co-factors (Mg++)
structure (calcium)
transport (iron)

Megadoses can seriously interfere with metabolism and absorption of minerals not taken in excess.

1. Get no more that 30% of daily calories from fat.
2. 10%-15% of daily calories should come from protein
3. The rest, (55%-60%) should come from carbohydrates.

We should consume less than 10% of our daily calories from saturated fat.
We should consume less than 10% of our daily calories from monounsaturated fat.
We should consume less than 10% of our daily calories from polyunsaturated fat.

We should consume about 300mg of dietary cholesterol per day.

Calories per gram of nutrient: FAT = 9
CARBOHYDRATE = 4
PROTEIN = 4
ALCOHOL = 7

1. Find the number of grams of fat per serving on the food label.
2. Multiply 9 x grams of fat. (1 gram of fat is equal to 9 calories)
3. Divide calories from fat by the total calories per serving to find the percent of calories from fat.

Example: Lays potato chips: 1 serving is 1/2 ounce
There are 80 calories in 1/2 oz. of Lays potato chips.
There are 5 grams of fat in 1/2 oz. of Lays potato ships.

9 x 5 = 45 calories from fat.
45/80 = 56% of the calories in Lays potato chips come from fat.

44% from butter, margarine, oils, shortening, mayonnaise, etc.

34% from meat, poultry, fish

15% from dairy products

7% from all other sources

To reduce the fat in the diet you have to reduce both the visible fat in your diet and the "invisible fat" in your diet.

Visible fat includes that in oils, margarine, the fat in meat, etc.
Invisible fat includes the fat "hidden" in processed foods, crackers, cookies, pastries, etc.

Reminders: Serum Cholesterol: the level of cholesterol circulating in the blood: includes that produced by the liver and that
consumed in the diet.

Dietary Cholesterol: that is present in the foods we eat. (present in animal products)

There is no cholesterol in any vegetable product, but there might be a lot of saturated fat
(which raises serum cholesterol level)

1979 - 129 lbs. per person per year
1989 - 87 lbs. Per person per year

Problems with sugar: "empty" calories. We eat more sugar due to low fat diets.

The body needs about 200mg of sodium per day.
The dietary guidelines suggest between 1100-3300mg per day.
The average American eats between 4000-12000mg per day.
(It is almost impossible to eat real food and consume less that 1000mg of sodium per day.)

Problems with too much sodium: hypertension, edema

1979 - 40% of calories from fat
1989 - 37% of calories from fat
1992 - 34% of calories from fat
(Goal - less than 30% of calories from fat)

Problems with too much fat: obesity, heart disease, stroke, high blood pressure, some cancers, diabetes in some.