Professor Lloyd M. Kahn
9 January 2012
1. Relate the importance of variety in a diet, especially with regard to fruit and vegetable choices, to the discovery of various phytochemicals in foods.
Variety is of vital importance when deciding what to eat. Not only does it help ensure that a diet contains sufficient nutrients, but also makes meals more interesting rather than eating the “same old thing” day after day. This approach is also best because no one particular food choice meets all of a person’s nutrient needs. For example, although carrots have a rich source of a pigment that forms vitamin A, you are neglecting various other nutrients found only in other vegetables. In this regard, diversity in your diet is essential because the required nutrients are scattered among many foods. As an added bonus, research has found that numerous fruits and vegetables contain rich supplies of phytochemicals, many of which provide significant health benefits. Studies have repeatedly shown that those who consume these types of foods regularly can reduce the risk of certain diseases such as cancer. Due to this, fruits and vegetables rich in such chemicals are now part of a family of foods referred to as functional foods. This is defined as a food that provides health benefits beyond those supplied by the traditional nutrients it contains.
2. How would you explain the concepts of nutrient density and energy density to a fourth grade class?
Density means how much you get of one thing given the presence of something else. A nutrient is a substance in food that the body needs in order to work properly. In the case of nutrient density, the “things” you receive, the nutrients, are compared to how many total calories that particular food contains. A food is said to be nutrient dense if it gives you a large amount of a nutrient for a small amount of calories. For instance, let’s say you get to choose whether to eat an apple or a glazed donut which are about the same size. The apple has around 80 calories and a lot of vitamins, fiber, and phytochemicals that will keep you healthy. The fiber and water in the apple will also help fill your stomach much faster and prevent you from eating too much. The donut, on the other hand, has a bunch of calories but has very little nutrients and a lot of saturated fat and plenty of sugar, both of which are very unhealthy . There is only about one gram of fiber so it won’t help keep you full either which will make you want to eat a second or even third one, which adds even more unhealthy choices. For this reason, the apple is said to be much more “nutrient dense” than the donut, even though they are about the same size. Energy density, on the other hand, is determined by comparing the calorie amount with the weight of the food. An “energy-dense” food is high in calories but weighs very little, like Potato Chips. An example of a food that is low in energy density, where it has few calories but weights a lot, would be an orange. As a result, it is safe to assume that foods with lots of water and fiber provide low-energy-density to a meal and helps you feel full, whereas foods with high energy density must be eaten in greater amounts to help you feel fuller. This is another reason to eat a diet that has many fruits, vegetables, and whole-grain breads and cereals since it will help keep your hunger under control.
3. Trace the progression, in terms of physical results, of a person who went from an over-nourished to an under-nourished state. In terms of physical results, a person who went from an over-nourished to an under-nourished state would see drastic physical changes. To start, the individual would be visibly obese due to the excess calories that the body does not need. He/she would also fatigue very easily, experience digestive problems, have trouble sleeping, and depending on the severity, the individual could also develop serious and sometimes fatal diseases such...