How to Increase Calories in Your Underweight Child’s Diet: A Gentle, Nutrient-Dense Approach

When a child is underweight—whether due to medical issues, feeding challenges, sensory sensitivities, or recovery from an eating disorder—one of the most urgent needs is to help them restore weight safely and sustainably. As a parent or caregiver, this can be incredibly stressful, especially if your child struggles with appetite, anxiety around food, or limited food preferences.

The good news is that small, consistent changes can make a big difference. Increasing calories doesn't mean force-feeding or pushing unfamiliar meals. It often involves strategic additions, gentle encouragement, and high-calorie foods that pack a nutritional punch without overwhelming your child.

When Is a Child Considered Underweight?

A child may be considered underweight when their body mass index (BMI) is below the 5th percentile for age and sex—or when there is a drop across two or more major growth percentiles on their growth chart. However, weight is only one part of the picture.

Other signs that weight gain may be needed include:

• Slowed or halted growth in height

• Loss of appetite or early satiety

• Fatigue, cold intolerance, or low energy

• Missed developmental milestones

• Hormonal changes (e.g., delayed puberty or missed periods in teens)

Always consult your child’s pediatrician or a pediatric dietitian before making major changes, especially if your child has a feeding disorder, medical condition, or is in recovery from an eating disorder.

Principles of Caloric Support for Underweight Children

1. Prioritize Energy Density

Energy-dense foods provide more calories in smaller portions. This is especially helpful if your child:

• Gets full quickly

• Has a small appetite

• Experiences nausea or bloating

2. Aim for Balanced Macronutrients

While calories are important, they should come from a balance of fats, proteins, and carbohydrates, along with vitamins and minerals to support healthy growth and development.

3. Consistency is Key

Frequent meals and snacks—every 2–3 hours—help prevent energy dips and promote steady intake throughout the day.

4. Focus on Additions, Not Restrictions

Rather than removing foods, the focus should be on what you can add to increase calories in meals your child already enjoys.

Strategies to Increase Calories Safely

1. Add Healthy Fats

Fats are the most calorie-dense macronutrient, providing 9 calories per gram.

Easy ways to add fat to meals:

• Mix olive oil or avocado oil into pasta, rice, or cooked vegetables

• Spread nut butters (peanut, almond, sunflower seed) on toast, fruit, or crackers

• Add avocado to sandwiches, smoothies, or eggs

• Use full-fat dairy (yogurt, cheese, milk) instead of low-fat options

• Stir cream cheese or sour cream into mashed potatoes or soups

2. Use Calorie-Rich Toppings and Mix-Ins

• Add shredded cheese to scrambled eggs, casseroles, or wraps

• Sprinkle chia seeds, hemp seeds, or ground flaxseed into yogurt or oatmeal

• Top pancakes or toast with butter and syrup or nut butter and honey

• Mix powdered milk or heavy cream into hot chocolate or milkshakes

3. Offer Smoothies and Shakes

High-calorie smoothies can be nutrient-packed and easier to consume than solid meals.

Sample ingredients:

• Whole milk or Greek yogurt

• Peanut butter or almond butter

• Banana or mango

• Full-fat coconut milk or avocado

• Oats or protein powder

• Honey or maple syrup

A small smoothie can provide 400–600+ calories with minimal volume.

4. Build Snack Routines

Snacks should be substantial and predictable, not just fillers.

Examples of calorie-rich snacks:

• Cheese and crackers

• Trail mix with dried fruit and nuts

• Granola bars dipped in nut butter

• Hummus with pita bread

• Mini bagels with cream cheese

• Hard-boiled eggs with avocado toast

5. Enhance Familiar Foods

Rather than introducing unfamiliar high-calorie foods, enrich the meals your child already eats:

• Add butter to rice or noodles

• Mix oil into spaghetti sauce

• Add grated cheese to soups or baked potatoes

• Stir peanut butter into oatmeal or cereal

Calorie Boosting for Picky or Sensory-Evasive Eaters

If your child is selective with food textures, flavors, or temperatures:

• Stick with preferred foods but make them higher in calories

• Use smooth, blended textures if chewing is an issue

• Offer cold options like smoothies, puddings, or energy bites

• Use visual tools like “food bridges” to expand variety slowly

• Avoid pressure—positive exposure over time is more effective than force

Special Considerations

If Your Child Is Recovering From an Eating Disorder:

Work with a team including a pediatrician, therapist, and registered dietitian. Weight restoration should be medically supervised and accompanied by psychological support.

If There Are Medical Concerns:

Children with conditions like ARFID (Avoidant/Restrictive Food Intake Disorder), POTS, celiac disease, or GI disorders may need:

• Customized meal plans

• Supplementation (e.g., high-calorie formula)

• Feeding therapy or OT support

Always seek individualized care.

What About Supplements?

Pediatric nutrition supplements (like PediaSure, Kate Farms, or Boost Kid Essentials) can help increase calories if food intake is insufficient. These can be used between meals or as part of a snack. Talk to your child’s provider before starting.

Signs of Progress (Beyond the Scale)

While weight gain is a key goal, look for other signs that your child is improving:

• Increased energy

• Improved mood

• Return of natural hunger cues

• More flexibility and enjoyment around food

• Growth in height and developmental milestones

Final Thoughts

Supporting your underweight child’s nutrition is a process—and it doesn’t have to be perfect. What matters most is consistency, compassion, and connection. Every small calorie addition, every bite without pressure, every step toward trust in food adds up.

You’re not just feeding a body—you’re helping rebuild growth, resilience, and well-being.

References

• Academy of Nutrition and Dietetics. (2022). Nutrition Care Manual: Pediatric Weight Gain.

• Mehler, P. S., & Andersen, A. E. (2015). Eating Disorders: A Guide to Medical Care and Complications.

• Neumark-Sztainer, D. (2005). I’m, Like, SO Fat!: Helping Your Teen Make Healthy Choices about Eating and Exercise in a Weight-Obsessed World.

• American Academy of Pediatrics. (2020). Clinical Report: Identification and Management of Eating Disorders in Children and Adolescents.