Begin from Infancy:

Breast-feeding is a natural form of nutrition which is sufficient to nourish ideal growth for about the first 4 to 6 months after birth. It should be maintained for at least 18 months. Moving on to other sources of nutrients should begin at about 4–6 months of age to ensure provision of adequate micronutrients in the diet.
Do not start complete juice intake until at least 6 months of the baby’s age and limit to no more than 4–6 oz/day. It should only be fed in cups.
Never over-feed infants and young children — they have ability to usually self-regulate the amount of calories they need each day. Children shouldn't be forced to finish meals completely if they aren't hungry as caloric intake often varies from meal to meal.
Try to introduce healthy meal even if they are refused to be taken. Don't introduce foods without overall nutritional value simply to provide calories.

This eating pattern for families is recommended by the American Heart Association (AHA):

• To reach or keep desirable body weight, energy (calories) should be in sufficient quantity to support growth and development.
• Take meals low in saturated fat, trans-fat, cholesterol, salt (sodium), and added sugars.
• Keep total fat intake between 30 to 35% of calories for children 2 to 3 years of age and between 25 to 35% of calories for children and adolescents 4 to 18 years of age, with most fats coming from sources of polyunsaturated and monounsaturated fatty acids, such as fish, nuts and vegetable oils.
• To get enough carbohydrates, protein and other nutrients, choose a variety of foods.
• To maintain a healthy weight for your height and build, eat only enough calories.
• Be physically active for at least 60 minutes a day.
• Serve whole-grain/high-fiber breads and cereals instead of refined grain products.
• Look for “whole grain” as the first ingredient on the food label and make at least half your grain servings whole grain.
• Recommended grain intake ranges from 2 oz./day for a one-year-old to 7 oz./day for a 14–18-year-old boy.
• Serve a variety of fruits and vegetables daily, while limiting juice intake.
• Each meal should contain at least 1 fruit or vegetable.
• Children’s recommended fruit intake ranges from 1 cup/day, between ages 1 and 3, to 2 cups for a 14–18-year-old boy.
• Recommended vegetable intake ranges from ¾ cup a day at age one to 3 cups for a 14–18-year-old boy.
• Introduce and regularly serve fish as an entrée.
• Avoid commercially fried fish.
• Serve fat-free and low-fat dairy foods.
• From ages 1–8, children need 2 cups of milk or its equivalent each day.
• Children ages 9–18 need 3 cups.
• Don’t overfeed. Estimated calories needed by children range from 900/day for a 1-year-old to 1,800 for a 14–18-year-old girl and 2,200 for a 14–18-year-old boy.

Conclusion:

This eating pattern supports a child's normal growth and development. It provides enough total energy and meets or exceeds the recommended daily allowances for all nutrients for children and adolescents, including iron and calcium.

Daily Estimated Calories and Recommended Servings for Grains, Fruits, Vegetables, and Milk/Dairy by Age and Gender:

Source:
American Heart Association