Section 1: Macronutrients (Carbohydrates, Proteins, and Fats)

What are carbohydrates composed of?

Carbon, hydrogen, and oxygen. 1

What are the main functions of carbohydrates?

To supply energy and serve as the structural framework of plants.

What is the only animal source of carbohydrate?

Lactose, found in milk.

How are carbohydrates classified?

As simple sugars or complex carbohydrates (starches).

What percentage of total adult calories should come from carbohydrates?

45% to 60%.

What is the relationship between income and carbohydrate intake?

As income increases, carbohydrate intake often decreases.

What percentage of carbohydrate intake is typically ingested?

About 90%.

How are carbohydrates converted for transport through the body?

They are converted to glucose and transported through the blood.

Which body system relies almost exclusively on glucose for energy?

The nervous system.

How does the liver regulate blood glucose?

It stores glucose and regulates its release into the bloodstream.

What are proteins made of?

Amino acids (22 types total).

What are the main functions of proteins?

Building body tissue, forming enzymes, hormones, and supporting growth.

What is a complete protein?

One that contains all essential amino acids in sufficient amounts to support growth.

What are incomplete proteins?

Those that lack one or more essential amino acids.

Which foods contain complete proteins?

Animal proteins like meat, eggs, and dairy — plus soy and quinoa.

How can vegetarians get complete proteins?

By combining different plant sources (e.g., rice and beans).

Where are dietary proteins broken down?

In the small intestine by pancreatic enzymes.

What happens to amino acids after absorption?

They go to the liver, where they are recombined or used by cells and tissues.

What does “anabolism” mean?

The building or synthesis of new tissue from amino acids.

What does “catabolism” mean?

The breakdown of tissue into amino acids.

What is the Recommended Dietary Allowance (RDA) for protein in adults?

0.8 grams per kilogram of body weight (10–35% of total calories).

What elements make up fats?

Carbon, hydrogen, and oxygen.

What percentage of dietary lipids are triglycerides?

About 95%.

What are saturated fats?

Fats that raise cholesterol levels; mostly found in animal sources.

What are unsaturated fats?

Fats that lower cholesterol; mostly from plant sources.

Where does fat digestion occur primarily?

In the small intestine.

What role does bile play in fat digestion?

It emulsifies fat, breaking it down for digestion by pancreatic enzymes.

How are fats absorbed and transported in the body?

Through the lymphatic system to the liver.

What is the most concentrated source of energy in the diet?

Fats.

What is the recommended limit for saturated fats?

Less than 10% of daily calories.

What should intake of trans fats be?

As low as possible.

What is trans fat and how is it formed?

A type of fat created when manufacturers partially hydrogenate liquid oils.