Targosz - Fit and Healthy for Dummies, Two eBook Bundle with Bonus Mini eBook: Nutrition for Dummies, Fitness for Dummies, and Ten Minute Tone-Ups for Dummies

Part I

The Basic Facts about Nutrition

In this part...

To use food wisely, you need a firm grasp of the basics. This part defines nutrition and offers a detailed explanation of digestion (how your body turns food into nutrients). It also documents the expansion of the average American body, explains why calories are useful, and sets forth a no-nonsense starter guide to your daily requirements of vitamins, minerals, and other good stuff.

Chapter 1

Whats Nutrition, Anyway?

In This Chapter

Exploring why nutrition matters

Determining the value of food

Locating reliable sources for nutrition information

Finding out how to read (and question) a nutrition study

Y ou are what you eat. You are also how you eat. And when you eat.

Choosing a varied diet of healthful foods supports any healthy mind and body, but which healthful foods you choose says much about your personal tastes as well as the culture from which you come.

How you eat may do the same: Do you use a knife and fork? A pair of sticks? Your hands and a round of bread? Each is a cultural statement. As for when you eat (and when you stop), that is a purely personal physiological response to signals from your digestive organs and your brain: Get food now! or Thank you, thats enough.

If you read chapter by chapter through this book, you can follow what you eat and drink as it moves from your plate to your mouth to your digestive tract and into every tissue and cell. Along the way, you discover how your organs and systems work. You observe firsthand why some foods and beverages are essential to your health. And you find out how to manage your diet so that you can get the biggest bang (nutrients) for your buck (calories).

Nutrition Equals Life

Technically speaking, nutrition is the science of how the body uses food. In fact, nutrition is life. All living things, including you, need food and water to live. Beyond that, you need good food, meaning food with the proper nutrients, to live well. If you dont eat and drink, youll die. Period. If you dont eat and drink nutritious food and beverages:

Your bones may bend or break (not enough calcium).

Your gums may bleed (not enough vitamin C).

Your blood may not carry oxygen to every cell (not enough iron).

And on, and on, and on. Understanding how good nutrition protects you against these dire consequences requires a familiarity with the language and concepts of nutrition. Knowing some basic chemistry is helpful. (Dont panic: Chemistry can be a cinch when you read about it in plain English.) A smattering of sociology and psychology is also useful because although nutrition is mostly about how food revs up and sustains your body, its also about the cultural traditions and individual differences that explain how you choose your favorite foods (see Chapter 15).

To sum it up: Nutrition is about why you eat what you eat and how the food you get affects your body and your health.

First principles: Energy and nutrients

Nutritions primary task is figuring out which foods and beverages (in what quantities) provide the energy and building material you need to construct and maintain every organ and system. To do this, nutrition concentrates on foods two basic attributes: energy and nutrients.

Energy from food

Energy is the ability to do work. Virtually every bite of food gives you energy, even when it doesnt give you nutrients. The amount of energy in food is measured in calories, the amount of heat produced when food is burned (metabolized) in your body cells. You can read all about calories in Chapter 3. But right now, all you need to know is that food is the fuel on which your body runs. Without enough food, you dont have enough energy.

Nutrients in food

Nutrients are chemical substances your body uses to build, maintain, and repair tissues. They also empower cells to send messages back and forth to conduct essential chemical reactions, such as the ones that make it possible for you to

Breathe

Move

Eliminate waste

Think

See

Hear

Smell

Taste

... and do everything else natural to a living body.

Food provides two distinct groups of nutrients:

Macronutrients (macro = big): Protein, fat, carbohydrates, and water

Micronutrients (micro = small): Vitamins and minerals

Whats the difference between these two groups? The amount you need each day. Your daily requirements for macronutrients generally exceed 1 gram. (For comparisons sake, 28 grams equal 1 ounce.) For example, the average man needs about 63 grams of protein a day (slightly more than 2 ounces), and the average woman needs about 50 grams (slightly less than 2 ounces).

Your daily requirements for micronutrients are much smaller. For example, the Recommended Dietary Allowance (RDA) for vitamin C is measured in milligrams (11,000 of a gram), while the RDAs for vitamin D, vitamin B12, and folate are even smaller and are measured in micrograms (11,000,000 of a gram). You can find out much more about the RDAs, including how they vary for people of different ages, in Chapter 4.

Whats an essential nutrient?

A reasonable person may assume that an essential nutrient is one you need to sustain a healthy body. But who says a reasonable person thinks like a nutritionist? In nutritionspeak, an essential nutrient is a very special thing:

An essential nutrient cannot be manufactured in the body. You have to get essential nutrients from food or from a nutritional supplement.

An essential nutrient is linked to a specific deficiency disease. For example, people who go without protein for extended periods of time develop the protein-deficiency disease kwashiorkor. People who dont get enough vitamin C develop the vitamin Cdeficiency disease scurvy. A diet rich in the essential nutrient cures the deficiency disease, but you need the proper nutrient. In other words, you cant cure a protein deficiency with extra amounts of vitamin C.