Introduction to Nutrition

What is a calorie?
A calorie is the unit that measures the energy value of food or the amount of energy it takes to do a particular activity.

Why should we learn calories?

1. Calories measure both intake and output of energy. Calorie balancing is one of the keys to weight management
2. Calories in foods and beverages come from 4 sources: protein, carbohydrates, alcohol, and fat.

1. Each gram of protein and carbohydrate contains 4 calories. Alcohol contains 7 calories per gram and essentially acts as a carbohydrate. Fat contains 9 calories per gram.

2. Excess calories consumed (especially calories from carbohydrates) and not used by the body are stored as fat. It takes an excess 3,500 calories to gain one pound. It takes a deficit of 3,500 calories to lose one pound of body fat.
   

What are fats and why are they important?
Fats in the diet are required in small amounts for your body to carry on vital functions. There are different types of fats:
1. Body Fat

1. Fat is an excellent source of stored energy. You will be burning off this stored fat during active weight loss.

2. Protects body organs from injury.

3. Provides insulation, helping the body to maintain temperature.

4. Regulation of hormones.

2. Dietary Fat

1. Aids in the absorption of the fat-soluble vitamins A, D, E, and K.

2. Polyunsaturated fats (from vegetable oils) supply our bodies with the essential fatty acid linoleic acid. Linoleic acid is known as an essential fatty acid because the body cannot manufacture it.

3. Enhances the flavor of foods and provides a desirable texture.

4. Provides satiety because it is digested more slowly than other nutrients. Fat also stimulates brain chemical that reduce appetite. Therefore, it delays the onset of hunger.

5. Saturated fats are solids at room temperature (e.g., butter, lard, and margarine). Unsaturated fats are liquid at room temperature (e.g., oils).

6. The best fat is olive oil.
   

What are carbohydrates?
A carbohydrate is a nutrient made up of the elements carbon, hydrogen, and oxygen. There are two types of carbohydrates: simple and complex. Simple carbohydrates are composed of one or two sugar units and are therefore easily broken down and absorbed into our blood stream rapidly. Examples include glucose and the sugars found in fruit and milk. Complex carbohydrates are composed of long chains of sugar units and are therefore absorbed slower that simple carbohydrates. These include whole grains, vegetables, and legumes (beans).

Why do we need complex carbohydrates?

1. Source of dietary fiber

2. Source of vitamins, minerals, and proteins

3. However, because carbohydrates cause increased fat deposition, they need to be limited.
   
   

What about protein?

Protein is a component of all cells in your body. Adequate protein is essential for good health. Protein performs many vital functions:

1. Protein is a component of skin, muscle, bone, cartilage, and blood.

2. Enzymes are made of protein which help to extract energy from the food we eat.

3. Hormones are proteins.

4. Protein maintains fluid balance.

5. Protein makes scar tissue and the visual pigment that lets us see.

6. Protein provides a protective coating for the body in the form of hair, skin, and nails.

7. Protein carries nutrients to and from cells.

8. Antibodies are made up of proteins that fight disease.

9. Protein serves as a component of hemoglobin, which carries oxygen in the blood.

10. Protein is essential for blood clotting.

11. Protein is essential for increased glucagon—the hormone that balances insulin, therefore decreasing fat deposition.
    
    

What are some sources of protein other than animal protein?
Examples of complimentary protein relationships:

1. Legumes (beans) + grains = complete protein

2. Legumes + dairy products = complete protein

3. Grains + dairy products = complete protein

4. Leafy green vegetables + dairy products = complete protein

5. Vegetables + grains = complete protein
   
   

Fiber – what about it?
High fiber foods help stabilize your blood sugar and keep you fuller longer. There are two kinds of fiber: water-soluble and water-insoluble fiber.

Water-soluble fiber forms a gel and slows down the rate of digestion thereby helping to stabilize the blood sugar. It also absorbs bile salts that help to reduce blood cholesterol. Water-soluble fiber is found in oatmeal, legumes, and fruit.

Water-insoluble fiber is important to help you get full at a meal and to keep you fuller longer. You will be less tempted to snack between meals. Water-insoluble fiber is found in whole grain breads and cereals, potatoes, brown rice, vegetables, and fruits.

Dr. Padla