1. Six Classes of Nutrients
Carbohydrates
Lipids
Proteins
Vitamins
Minerals
Water
Only carbs, lipids, and proteins yield energy
2nd edit BTT2 3/06 AD

2. Carbohydrates Combinations of C, H, & O
Storage forms of energy. Assembled by plants via photosynthesis.
CO2 + H2O  CHO + O2
Some digestible = energy for us
Some indigestible = no energy but many health benefits

3. 3 Forms of Carbohydrates
Monosaccharides
“simple” sugars
E.g. glucose, fructose, galactose
Absorbed directly into blood through sm. I. and sent to liver
Glucose:
Liver may allow G directly into blood OR store it as glycogen
A favorite fuel of virtually all body cells
Is “only” fuel used by brain cells
May be stored in muscle cells as glycogen
Excess will be converted to FAT by fat cells

4. Glucose cont’d Can be stored by linking G together
If stored in plants… = starch
Long strands of thousands of G
If stored in animals… = glycogen
Long strands of tens of thousands of G

5. 3 Forms of Carbohydrates
Monosaccharides cont’d
Galactose
Appears as starches are broken down
Rarely remains as galactose for long
Is converted by the liver to glucose and released to blood
Fructose
Used by liver as fuel
Excess is broken down to building blocks of fat
Occurs naturally in fruits and honey
Sweeter tasting so may use less
HFCS
High Fructose Corn Syrup
Made by adding enzymes to corn starch to convert Glucose to fructose.
More likely to be stored as FAT

6. 3 Forms of Carbohydrates
2) Disaccharides
Differing combinations of 2 monosaccharides
But still considered “simple” sugars
E.g. maltose, sucrose, lactose
Easily digested into ‘monos’ by cells lining sm. I.

7. 3 Forms of Carbohydrates cont’d
3) Polysaccharides
Consist of 100s/1000s of G monosaccharides
Known as “complex” carbs
Storage polysaccharides
E.g. glycogen in animals
E.g. starch in plants
Structural polysaccharides
E.g. fiber (e.g. cellulose - cell walls of plants)
Bonds not digestible
Soluble – absorbs water
Insoluble – does
not absorb…

8. Carbs: Sources and Summary
Great source of glucose
4 Calories/gram
Less expensive source of energy than proteins
Used w proteins for cell identity markers
Used for mucus production
Often pkged w vitamins, minerals, trace nutrients
Helps avoid ketoacidosis

9. Carbs: Advantages of Complex Carbs
IF complex and/or rich in fiber…
Prevents constipation
Reduces risk of colon cancer
Helps you feel full and eat less
Stabilizes blood sugar (prevents ‘spikes’)
Best sources: whole grain breads, beans, fruits, veggies
Worst sources: 1) any food/drink w refined sugar added
2) animal products