Balanced Diet and Nutrition: A Guide to Healthy Eating

Balanced Diet and Nutrients

We need to eat a wide variety of foods to obtain all the necessary substances. A diet that includes a variety of foods is called a balanced diet. Carbohydrates, proteins, fats and oils (lipids), vitamins, and minerals are essential nutrients. These nutrients provide the raw materials our bodies need to function properly.

Food Testing

We can conduct tests to identify the substances present in our food. For example, starch turns iodine a blue-black color.

Nutrition Information Labels

Nutrition information labels on food products tell us about the food's composition and the amount of energy stored within it. Energy is measured in kilojoules (kJ). A person's daily energy needs depend on several factors:

• Level of activity
• Age
• Gender

Food labels may also include health claims, often using persuasive language.

Impact of Diet

Consuming too much or too little food can lead to health problems. Excessive fat intake may contribute to heart disease and obesity. Insufficient food intake can cause starvation and weakness. Both starvation and obesity are forms of malnutrition. Other forms include deficiency diseases such as scurvy, which results from a lack of vitamin C.

Digestion

Digestion breaks down large, insoluble substances into smaller, soluble ones. The organs of the digestive system facilitate this process, many of which produce enzymes to aid in the breakdown and absorption of food.

The Small Intestine

The wall of the small intestine is folded and covered with villi. The cells on the villi have microvilli. These features significantly increase the surface area available for nutrient absorption. The small intestine's wall is only one cell thick, allowing for easy diffusion of small molecules into the bloodstream. Digested food molecules are then transported in the blood plasma.

Surface Area to Volume Ratio

Surface area is the total area of the faces of a three-dimensional object. Volume is the amount of space the object occupies. An object's surface area to volume ratio is its surface area divided by its volume. A larger surface area to volume ratio means an object has more surface area per unit volume. Cells require a large surface area to volume ratio to efficiently absorb the necessary substances from their surroundings.