romancya's Blog

You probably know you need to eat protein, but what is it? Many foods contain protein (say: pro-teen), but the best sources are beef, poultry, fish, eggs, dairy products, nuts, seeds, and legumes like black beans. Protein builds up, maintains, and replaces the tissues in your body. (Not the tissues you blow your nose in! We mean the stuff your body's made up of.) Your muscles, your organs, and your immune system are made up mostly of protein.

Your body uses the protein you eat to make lots of specialized protein molecules that have specific jobs. For instance, your body uses protein to make hemoglobin (say: hee-muh-glow-bin), the part of red blood cells that carries oxygen to every part of your body. Other proteins are used to build cardiac muscle. What's that? Your heart! In fact, whether you're running or just hanging out, protein is doing important work like moving your legs, moving your lungs, and protecting you from disease.

All About Amino Acids

When you eat foods that contain protein, the digestive juices in your stomach and intestine go to work. They break down the protein in food into basic units, called amino acids (say uh-me-no ah-sids). The amino acids then can be reused to make the proteins your body needs to maintain muscles, bones, blood, and body organs.

Proteins are sometimes described as long necklaces with differently shaped beads. Each bead is a small molecule called an amino acid. These amino acids can join together to make thousands of different proteins. Scientists have found many different amino acids in protein, but 22 of them are very important to human health.

Of those 22 amino acids, your body can make 13 of them without you ever thinking about it. Your body can't make the other nine amino acids, but you can get them by eating protein-rich foods. They are called essential amino acids because it's essential that you get them from the foods you eat.

Different Kinds of Protein

Protein from animal sources, such as meat and milk, is called complete, because it contains all nine of the essential amino acids. Most vegetable protein is considered incomplete because it lacks one or more of the essential amino acids. This can be a concern for someone who doesn't eat meat or milk products. But people who eat a vegetarian diet can still get all their essential amino acids by eating a wide variety of protein-rich vegetable foods.

For instance, you can't get all the amino acids you need from peanuts alone, but if you have peanuts or peanut butter on whole-grain bread you're set. Likewise, red beans won't give you everything you need, but red beans and rice will do the trick. The good news is that you don't have to eat all the essential amino acids in every meal. As long as you have a variety of protein sources throughout the day, your body will grab what it needs from each meal.

How Much Is Enough?

You can figure out how much protein you need if you know how much you weigh. Each day, kids need to eat about 0.5 grams of protein for every pound (0.5 kilograms) they weigh. That's a gram for every 2 pounds (1 kilogram) you weigh. Your protein needs will grow as you get bigger, but then they will level off when you reach adult size. Adults, for instance, need 60 grams per day.

To figure out your protein needs, multiply your weight in pounds times 0.5 or you can just take your weight and divide by 2. For instance, a 56-pound (or 25-kilogram) kid should have about 28 grams of protein every day. If you only know your weight in kilograms, you need about 1 gram of protein each day for every kilogram you weigh.

You can look at a food label to find out how many protein grams are in a serving. But if you're eating a balanced diet, you don't need to keep track of it. It's pretty easy to get enough protein. Here's an example of how a kid might get about 30 grams of protein in a day:

• 1 tablespoon (15 milliliters) peanut butter (4 grams protein)
• 1 cup (240 milliliters) low-fat milk (8 grams protein)
• 1 ounce (30 grams) or 2 domino-size pieces of cheddar cheese (7 grams protein)
• 1.5 ounces (90 grams) chicken breast (10.5 grams protein)

Of course, you can choose your own favorite combination of protein-rich foods - now that you're a pro at protein!

Reviewed by: Jessica R. Donze, RD, MPH
Date reviewed: March 2004

You've probably seen ads for low-carb foods and diets, but kids and adults need carbohydrates (say: kar-bo-hi-draytz). Most foods contain carbohydrates, which the body breaks down into simple sugars - the major source of energy for the body.

Two Types of Carbohydrates

There are two major types of carbohydrates in foods: simple and complex.

Simple carbohydrates: These are also called simple sugars. Simple sugars are found in refined sugars, like the white sugar you'd find in a sugar bowl. If you have a lollipop, you're eating simple carbohydrates. But you'll also find simple sugars in more nutritious foods, such as fruit and milk. It's better to get your simple sugars from food like fruit and milk. Why? Because they contain vitamins, fiber, and important nutrients like calcium. A lollipop does not.

Complex carbohydrates: These are also called starches. Starches include grain products, such as bread, crackers, pasta, and rice. As with simple sugars, some complex carbohydrate foods are better choices than others. Refined (say: ree-find) grains, such as white flour and white rice, have been processed, which removes nutrients and fiber. But unrefined grains still contain these vitamins and minerals. Unrefined grains also are rich in fiber, which helps your digestive system work well. Fiber helps you feel full, so you are less likely to overeat these foods. That explains why a bowl of oatmeal fills you up better than sugary candy that has the same amount of calories as the oatmeal.

So which type of carbs should you eat? Both can be part of a healthy diet.

How the Body Uses Carbohydrates

When you eat carbohydrates, the body breaks them down into simple sugars. These sugars are absorbed into the bloodstream. As the sugar level rises in your body, the pancreas releases a hormone called insulin. Insulin is needed to move sugar from the blood into the cells, where the sugar can be used as a source of energy.

When this process goes fast - as with simple sugars - you're more likely to feel hungry again soon. When it occurs more slowly, as with a whole-grain food, you'll be satisfied longer. These types of complex carbohydrates give you energy over a longer period of time.

The carbohydrates in some foods (mostly those that contain a lot of simple sugars) cause the blood sugar level to rise more quickly than others. Scientists have been studying whether eating foods that cause big jumps in blood sugar may be related to health problems like diabetes and heart disease. You're probably already on the right track if you are limiting simple sugars (such as candy) and eating more complex carbohydrates (like vegetables, oatmeal, and whole-grain wheat bread).

Reviewed by: Steven Dowshen, MD
Date reviewed: January 2005

"That's loaded with calories!"

"Are you counting your calories?"

When people talk about the calories in food, what do they mean? A calorie is a unit of measurement - but it doesn't measure weight or length. A calorie is a unit of energy. When you hear something contains 100 calories, it's a way of describing how much energy your body could get from eating or drinking it.

Are Calories Bad for You?

Calories aren't bad for you. Your body needs calories for energy. But eating too many calories - and not burning enough of them off through activity - can lead to weight gain.

Most foods and drinks contain calories. Some foods, such as lettuce, contain few calories. (A cup of shredded lettuce has less than 10 calories.) Other foods, like peanuts, contain a lot of calories. (A half of a cup of peanuts has 427 calories.)

You can find out how many calories are in a food by looking at the nutrition facts label. The label also will describe the components of the food - how many grams of carbohydrate, protein, and fat it contains. Here's how many calories are in 1 gram of each:

• carbohydrate - 4 calories
• protein - 4 calories
• fat - 9 calories

That means if you know how many grams of each one are in a food, you can calculate the total calories. You would multiply the number of grams by the number of calories in a gram of that food component. For example, if a serving of potato chips (about 20 chips) has 10 grams of fat, 90 calories are from fat. That's 10 grams X 9 calories per gram.

Some people watch their calories if they are trying to lose weight. Most kids don't need to do this, but all kids can benefit from eating a healthy, balanced diet that includes the right number of calories - not too many, not too few. But how do you know how many calories you need?

How Many Calories Do Kids Need?

Kids come in all sizes and each person's body burns energy (calories) at different rates, so there isn't one perfect number of calories that a kid should eat. But there is a recommended range for most school-age kids: 1,600 to 2,500 per day.

When they reach puberty, girls need more calories, but they tend to need fewer calories than boys. As boys enter puberty, they will need as many as 2,500 to 3,000 calories per day. But whether they are girls or boys, kids who are active and move around a lot will need more calories than kids who don't.

Most kids don't have to worry about not getting enough calories because the body - and feelings of hunger - help regulate how many calories a person eats. But kids with certain medical problems may need to make sure they eat enough calories. Kids with cystic fibrosis, for instance, have to eat high-calorie foods because their bodies have trouble absorbing the nutrients and energy from food.

Kids who are overweight might have to make sure they don't eat too many calories. (Only your doctor can say if you are overweight, so check with him or her if you're concerned. And never go on a diet without talking to your doctor!)

If you eat more calories than your body needs, the leftover calories are converted to fat. Too much fat can lead to health problems. Often, kids who are overweight can start by avoiding high-calorie foods, such as sugary sodas, candy, and fast food, and by eating a healthy, balanced diet. Exercising and playing are really important, too, because activity burns calories.

How the Body Uses Calories

Some people mistakenly believe they have to burn off all the calories they eat or they will gain weight. This isn't true. Your body needs some calories just to operate - to keep your heart beating and your lungs breathing. As a kid, your body also needs calories from a variety of foods to grow and develop. And you burn off some calories without even thinking about it - by walking your dog or making your bed.

But it is a great idea to play and be active for at least 1 hour and up to several hours a day. That means time spent playing sports, just running around outside, or riding your bike. It all adds up. Being active every day keeps your body strong and can help you maintain a healthy weight.

Watching TV and playing video games doesn't burn many calories at all, which is why you should try to limit those activities to 1 to 2 hours per day. A person burns only about 1 calorie per minute while watching TV, about the same as sleeping!

Reviewed by: Mary L. Gavin, MD
Date reviewed: March 2007

You know how books have a table of contents that explains what's inside? Or maybe you've received a toy that came with a diagram that identified each small piece. Nutrition labels are sort of like that. They tell you what's inside the food you're eating and list its smaller parts.

The Nutrition Facts food label gives you information about which nutrients (say: nu-tree-ents) are in the food. Your body needs the right combination of nutrients, such as vitamins, to work properly and grow. The Nutrition Facts food label is printed somewhere on the outside of packaged food, and you usually don't have to look hard to find it. Fresh food that doesn't come prepackaged sometimes has nutrition facts, too.

Most nutrients are measured in grams, also written as g. Some nutrients are measured in milligrams, or mg. Milligrams are very tiny - there are one thousand milligrams in a gram. Other information on the label is given in percentages. These numbers are based on eating 2,000 calories in a day, the amount that many school-age kids eat . A calorie is a unit of energy, a way of expressing how much energy you would get by eating a certain food.

If you want to learn more about the different types of information on food labels, keep reading. We'll start at the top of the label and work our way down.

Serving Size

The nutrition label always lists a serving size, which is an amount of food, such as 1 cup of cereal, two cookies, or five pretzels. The nutrition label tells you how many nutrients are in that amount of food. Serving sizes also help people understand how much they're eating. If you ate 10 pretzels, that would be two servings.

Servings per Container or Package

The label also tells you how many servings are contained in that package of food. If there are 15 servings in a box of cookies and each serving is 2 cookies, then you have enough for all 30 kids in your class to have one cookie each. Math comes in handy with food labels!

Calories and Calories From Fat

The number of calories in a single serving of the food is listed on the left of the label. This number tells you the amount of energy in the food. People pay attention to calories because if you eat more calories than your body uses, you might gain weight.

Another important part of the label is the number of calories that come from fat. People check this because it's good to limit fat intake. The calories in a food can come from fat, protein, or carbohydrate.

Percent Daily Value

You'll see percentages on food labels that are based on recommended daily allowances - meaning the amount of something a person should get each day. For instance, there's a recommended daily allowance for fat, so the food label might say that one serving of this food meets 10% of the daily value. The daily values are based on an adult's needs, not a kids' needs. These are often similar, but kids need may need more or less of certain nutrients, depending on their age and size.

Some percent daily values are based on the amount of calories and energy a person needs. These include carbohydrates, proteins, and fat. Other percent daily values - like those for sodium, potassium, vitamins, and minerals - stay the same no matter how many calories a person eats.

Total Fat

The total fat is the number of fat grams contained in one serving of the food. Fat is an important nutrient that your body uses for growth and development, but you don't want to eat too much. The different kinds of fat, such as saturated, unsaturated, and trans fat, will be listed separately on the label.

Cholesterol and Sodium

These numbers tell you how much cholesterol and sodium (salt) are in a single serving of the food. They are included on the label because some people need to limit cholesterol or salt in their diets. Cholesterol and sodium are usually measured in milligrams.