Food used to be made from staple items such as grains, vegetables and meats, but now it's canned, frozen and packaged using preservatives and additives into thousands of different food products. And it has gone from being made by us to being cooked and served to us by others in restaurants, fast food chains and other food outlets.
All of these changes have made eating more convenient, but less personal. At the same time, the many options now available make it hard for us to know what to choose for a healthy, wholesome meal, especially if we want to improve our eating habits.
What You Need to Know
It's important to understand where nutrients come from—and how and why they matter to our health. It's also important to know how foods are classified into food groups based on the nutrients they provide. But many foods can fit into more than one category or group! Grouping similar foods is important to help us track how much we get of each nutrient:
Food as a Source of Energy
At its most basic level, food is a source of energy and provides the building blocks needed by our body in order to function, grow and repair itself as we move through life. The energy available in a food is measured in calories provided by three nutrients (carbohydrate, protein and fat) and one non-nutrient (alcohol). Fats and alcohol provide approximately double the calories that protein and carbohydrates do. As noted on food labels:
- Carbohydrate = 4 calories per gram
- Protein = 4 calories per gram
- Fat = 9 calories per gram
- Alcohol = 7 calories per gram
Vitamins, minerals and water, while vital for normal function, do not give us a calorie source.
Did You Know?
A gram is the most widely used unit of measure for ingredients in cooking and groceries worldwide. One gram is roughly equivalent to the weight of a small paper clip.