19.4: From Toddler to Teen

The Slowing of Growth

During the first year of life, the body weight almost triples, and there’s about a 9 or 10 inch increase in height. The growth rate slows dramatically in the second year, and continues to slow through childhood (see Fig. 19-6).

Just before puberty, the growth rate increases (prepubertal growth spurt). Girls stop growing about 2 years after puberty. Boys usually reach puberty 2 to 4 years later than girls, and continue growing for 2 to 6 years after puberty.

The slowdown in that second year of life is dramatic. It’s not just growth rate that changes, but the whole pace of metabolism. The newborn’s heart beats about 130 times a minute; it slows to 100 at age two. Body temperature increases slightly through the first year, then begins to go down. Breathing goes from 30 breaths a minute in the first year to 25 in the second. These factors all contribute to the baby’s very high rate of metabolism, which then drops rapidly as the baby enters the toddler stage.

Toddlers may still eat a considerable amount of food, but less in relation to their size than during that first year of life. This slowdown in eating causes some parents to worry needlessly. But because they’re eating less, the nutrient density of their diet is important.

Figure 19-6: Body weight from birth to adulthood.

This explains why nutritionists are concerned with the nutritive qualities of children’s snacks. Snacks represent such a substantial portion of a typical child’s diet that they must be thought of, not as extra treats, but as small auxiliary meals.

Early Childhood—A Time to Start Good Habits

Age two is a milestone of sorts in terms of dietary guidelines. It’s at this age, for example, that we’re advised to heed the dietary guideline to limit solid fat (see Chap. 18). But parents shouldn’t go overboard. There have been instances where a child’s growth has been stunted because of overly strict restriction of fat and calories by well‑meaning parents.

Early childhood is a good time to begin instilling the basics of good nutrition—a time to learn about the nutritive value of various foods and the importance of a diet that includes a variety of foods. This is also a good time to start letting children participate in preparing meals, not only to familiarize them with what goes into what they eat, but also so that they can develop the skills and enjoyment of cooking.

In the nutrition education of a child, the central aim should be a future well-nourished adult. This is especially important as one begins to deal with the toddler, who is forming and expressing narrow preferences. We shouldn’t pass on to our children our culture’s esteem for the rich man’s diet—centered on meat, and heavy in solid fat.

Early childhood is when children learn to expect—or not expect—dessert after dinner. To expect—or not expect—a soft drink with the pizza. A bag of chips in the lunch-box. A cookie for being good. Nutrition is a family matter. It’s generally found that when a family’s food habits are good or poor, so are those of the children.

Variety is important in a balanced diet, and early childhood is a good time to introduce this variety. Although children commonly reject new foods when they are first given a taste, they usually acquire a taste for the foods after repeated tastings.⁶ So it is that Mexican children like hot salsa, Japanese children like seaweed, and American children like macaroni and cheese.

Besides establishing eating habits, early childhood is also a time of establishing other health habits, particularly exercise habits. Does the family recreation tend toward watching television together, or does it tend toward early evening walks to the playground?

It’s no mystery as to why good eating and exercise habits acquired in early childhood are key to maintaining good health and a healthy body weight throughout one’s lifetime.

The Things Kids Eat

It isn’t long before we start losing control over what the growing child eats. While we can do our best to see that nutritious snacks and meals are offered at day-care centers and schools, the choices widen for children as they grow older. Nevertheless, a lot of their food is still eaten at home—and they can’t eat what’s not there.

If a parent’s not home when the child comes home from school, there could be a sandwich and cut-up fruit ready for the after-school snack. And for a time, anyway, we have control over how much money they have available to buy food away from home.

We worry about their diet. After all, they tend to make such narrow food choices, with a taste for hot dogs, peanut butter, hamburgers, chips, soft drinks, and whatever is fried, frosted, or suitable for dipping. Yet, with only a few exceptions (e.g., iron intake is commonly low), most of them get enough of the required nutrients.

How can children include so much of what many parents call “junk” in their diet, yet still get enough nutrients to keep healthy and grow? The biggest reason is that the amount of food that children eat in proportion to their size is quite different from that of their parents.

For example, let’s compare the food intakes of a 10-year-old boy and his 30-year-old mother. He weighs 65 pounds, and she weighs 130—twice as much. Yet, the typical caloric need for each is the same—about 2,100 calories a day.

Next, consider the fact that, although the boy requires more nutrients relative to his body size, most of the boy’s RDAs are lower than his mother’s. For example, his protein RDA per pound body weight is higher than his mom’s (0.43 gm vs. 0.36 gm). But because he weighs so much less, the total amount of protein he needs each day is less: His protein RDA is 28 gm protein (0.43 gm/lb x 65 lb); hers is 47 gm (0.36 gm/lb x 130 lb).

His vitamin C RDA is 45 mg; hers is 75 mg. His iron RDA is 8 mg; hers is 18 mg. And so it goes. Compared to his mother, he needs to use a smaller part of those 2,100 calories to meet his nutrient needs.

He has many more extra calories to “spend” on such foods as candy bars and potato chips. His mother, however, often gets the impression that his diet, replete with “junk food,” is really much poorer than it is.

But children this age commonly stretch that extra capacity for luxury foods a bit too far. The delicate job of a parent is to make sure that foods containing the essential nutrients get first priority, and are eaten in adequate amounts. Once this is done, the child should still have plenty of room in the diet for the less nutritious foods.

Even “junk foods” are a source of nutrients. Ice cream has some of the merits of other milk products—and french fries drenched in catsup are derived from the vegetable group. “Junk foods” should not, however, make up a disproportionately large part of the diet, even at this age.

The larger nutritional concerns are those of the “typical American diet”—particularly the problem of excess calories. Alarmingly, obesity (see Chap. 4) and diabetes (see Chap. 5) are increasing and occurring at younger ages. One target in reducing calorie intake is cutting back on the soft drinks (“empty calories”) that children drink so much of. Also, drinking one’s calories is fast, so even fruit juice should be limited (encourage eating whole fruits). Water and milk should be the beverages of choice.

Children’s diets tend to get worse as they enter the adolescent years—all the more reason why it’s so important to develop good dietary habits in early childhood. Again, parents still have some control over what their adolescent eats at home.

Convenience is urgently critical to the typical teenager—especially teenage boys who come home from school ravenously hungry. (A published report tells of the teenager who took a jelly donut from freezer to microwave oven, jammed it in his mouth, and suffered a serious burn to the roof of his mouth from the scalding-hot jelly.) Small differences in convenience can change a choice. If the choice is cold water in the refrigerator or unchilled soft drinks in the back cupboard—you guessed it!

Plenty of physical activity can do much to counterbalance the worsening of the diet. Exercise increases the calorie need much more than the nutrient need. The most worrisome combination is a worsening diet and declining physical activity, as one’s physical growth comes to an end. This combination is common among adolescent girls as they become more weight conscious, less “tomboyish,” and stop growing—all at the same time.