Despite an obesity epidemic in this country, many toddlers and children are underweight. Parents repeatedly ask me how to help a child gain weight in a healthful way. This is an important question because the age-old advice of milkshakes and ice cream (or in my opinion even the sugar-laden Pediasure) just doesn't cut it, and can spark a cycle of insulin resistance that can lead an underweight child down a path toward obesity and diabetes.

Parents might want to focus less on the scale and instead direct their energy toward providing their children with enough macronutrients (protein, carbohydrates and fats) and micronutrients (vitamins and minerals). Empty calories, like those in ice cream, might add a few pounds here and there, but they will not provide the nutrients a child needs to build a healthy brain, resilient organs and strong bones. So if you have an underweight child, begin by ensuring all calories ingested are nutrient-rich.

              The following foods can help a child healthfully gain weight and thrive:

• Beneficial fats, especially plant-based fats. Each gram of fat has about nine calories while each gram of protein or carbohydrate provides about four calories, so a meal made with fats can contribute to wanted weight gain. Here are some recommended sources of healthful fat:
• Flaxseed oil. Add to it everything! Flaxseed oil has a mild flavor, so it will go unnoticed if mixed into a smoothie, drizzled onto popcorn or tossed with vegetables.
• Coconut oil. Coconut oil adds sweetness and beneficial calories, so add a tablespoon into a smoothie or to vegetables when roasting.
• Nuts and seeds. Pistachios, walnuts and almonds are great choices for kids.
•  Avocados. Make guacamole with fresh avocados, onions and tomatoes, or mix avocado into a fruit smoothie.
• Olives are about 80-85 percent healthful fat, and because of their high amounts of antioxidants and phytonutrients (a beneficial plant compound), they have been shown to help prevent disease.
• Full-fat dairy has more calories and fat than the reduced-fat varieties, yet a comparable amount of nutrients. We buy only full-fat dairy at our house, because everyone needs beneficial fats.
• Smoothies. Smoothies are an easy way to ingest needed nutrients and calories, especially if you add coconut oil, coconut milk or almond butter. Get creative with your favorite fruit, full-fat yogurt, nut butters and seeds.
• Grate cooked eggs into salads, sauces and soups.
• Cook pasta, rice and whole grains in chicken broth, adding extra nutrition and a few extra calories.
• Dried fruit lacks water, making it easier to eat more sizable quantities. This means a greater calorie intake.
• Make granola with nuts, seeds, dried fruit and coconut oil, then mix with full-fat Greek yogurt.
• Make trail mix with your choice of nuts, seeds and dried fruit.
• Hummus and bean dips make good snacks.
• Grated, frozen chicken liver provides children with essential nutrients such as protein, Vitamin A, all the B vitamins and iron. It doesn't greatly affect flavor when frozen and grated into food. My kids have never even noticed!

               Behavior and routine

• Drink after a meal, not during. Even water can fill up a little belly, tricking a child into feeling full. Milk and juice are more often the culprit as many toddlers and preschoolers drink so much throughout the day that they aren't hungry enough for food at mealtime.
• Set meal and snack times. Kids need to know that mealtime is an important and expected part of their day. Eating in the stroller or car conveys to your children that eating well is not a priority. Snack foods that parents can keep in the car are also often lower-nutrient foods.
• Sit down to meals with your children. They will eat more healthful foods if they see healthful eating modeled.
• Turn off the TV. Older children and adults tend to mindlessly eat in front of the television, but many young kids will be too captivated by the screen to eat at all.
• This might sound counterintuitive, but make sure your child is getting enough exercise. Yes, exercise burns calories, but it also ensures a child is hungry enough to eat well.
• Provide healthful snacks in between meals. Children's stomachs are small, so they cannot always eat enough food during their meals to meet their nutritional needs. Snacks also sustain a young child's energy and mood.
• Add a snack before bedtime. If the snack is full of healthful fat and protein, the nutrients can build tissue while sleeping. Avoid sugar so a child's ability to sleep is not affected.

Keep in mind that this approach to eating works for most kids, not just those who need to put on a few extra pounds.

For a recipe that is full of healthful calories, try these energy balls (see accompanying recipe). My children's friends often walk into our house and immediately ask whether I have any in the fridge or freezer; in other words, they are a crowd pleaser, and a nutrient-rich one.

        

Seidenberg is co-founder of Nourish Schools, a D.C. nutrition education company. Look for her posts on the On Parenting blog: washingtonpost.com/onparenting.