Failure to Thrive: What is it, What Causes it, How is it Managed and How to Add Allergy-Friendly Calories

Posted 4.26.12 | Mallory West

Failure to thrive (FTT) is a term used to describe a child who fails to gain weight at the expected rate or who loses weight over time. At each doctor’s visit, a child’s height, weight and head circumference are measured to make sure they are growing appropriately. Children come in all different sizes of course but the general growth trend during infancy and childhood should be fairly consistent.

Pediatricians use growth charts to track the growth of infants, children and adolescents. The growth charts are created by the National Center for Health Statistics at the Center for Disease Control.  FTT is often considered when a child is below the 3rd-5th percentile for age or weight or has fallen 2 major percentile lines on the growth charts[i].

What Causes FTT?

FTT occurs when an infant or child is unable to consume, retain, or utilize the nutrition and calories that they need to gain weight and grow appropriately.  Infancy and early childhood are a crucial period of physical and mental development, so doctors are concerned when growth is impaired.

There are many different causes of FTT but most often, it occurs as a result of an underlying medical issue[ii]. Below are some examples of conditions which can lead to the development of FTT.

  • Food allergies: Until they are diagnosed, food allergies can impair the body’s ability to absorb nutrients from food properly. Once food allergies are diagnosed, entire food groups may be eliminated from the diet. Such a restricted diet can make it difficult to get enough nutrition.
  • Gastrointestinal conditions(such as GERD, chronic diarrhea, celiac, etc)
  • Metabolic disorders
  • Infections/illnesses
  • Physical conditions (such as heart conditions, cleft palates, etc)

How is FTT Managed?

The child’s healthcare provider will determine the best course of treatment, depending on the underlying cause for the FTT. If the problem is caused by malabsorptionassociated with food allergies, dietary changes alone may resolve the issue. If the child has difficulty eating enough with such a restricted diet, they may need to supplement with an allergy-friendly formula like Neocateor E028 Splashin order to fill in the nutritional gaps.

When a child is having difficulty consuming enough calories, their healthcare provider may recommend some high-calorie snacks to boost their intake. For infants, they may recommend a high-calorie infant formula or they may recommend concentrating the current formulato make it more calorie dense. For older children who eat table foods, they may recommend adding a calorie supplement, like Duocal, to foods and trying to add high-calorie foods to their diet.  

Allergy-Friendly, High Calorie Foods:

The high-calorie foods you can use obviously depend on which foods your child is allergic to so if you are unsure which foods are safe and which are not, always consult with your pediatrician or other physician before adding any new foods.  Cheese, cream, milk powders and other dairy-based foods may be recommended for adding calories but since most of our readers have little ones with milk and other food allergies, we will list some high-calorie options not containing the top 8 allergens.

Avocados:I think avocados are the perfect food. Many adults avoid them because they think they are fattening, which in a sense they are, but they are packed full of the good fat (and tons of other important nutrients). Avocados are a healthy way to boost your child’s calorie intake. A 1 oz serving (about 2 tbsp) of fresh avocado contains 50 calories. You may be surprised to find that kids often love avocados. For the little ones, you can mash avocados and mix them with baby food fruits and vegetables or rice cereal (or Nutra). For older kids, you can mix them with table foods or make a guacamole dip.

Homemade fries: Make your own French-fries by slicing potatoes or sweet potatoes and frying them in a heart-healthy oil, such as olive oil. You can also fry other vegetables like zucchini, eggplant, mushrooms etc. Each tablespoon of olive oil contains nearly 120 calories!

Sunflower seed butter:Nut butters are often used to add calories and protein to a child’s diet but peanuts and tree nuts are among the top 8 allergens. Instead, you might consider sunflower seed butter, which has a similar flavor and texture. 2 tbsp of sunflower seed butter contains 200 calories and 7 g of protein.

Smoothies:Smoothies are a great way to pack in a bunch of nutrients.  Add fruits like bananas, berries, peaches, etc. I like to use frozen fruits so that you don’t need as much ice.  Add a liquid of choice, such as fruit juice or a milk-alternative such as rice milk, coconut milk or Neocate.  If desired, add some ice. For some more bulk, you can also add an allergy-friendly yogurt or frozen dessert, like coconut yogurt (dairy-free) or sorbet (be sure it’s a dairy-free, soy-free brand). Add a few scoops of Duocalto pack some extra calories (each scoop adds 25 calories; Duocalis milk protein-free).  Blend it all together and you have a tasty, high calorie, easy-to-transport drink.

Dried fruits:Dried fruits are a high-calorie, nutritious snack that is easy to take along with you on the go. Dried fruits lose their water content so you get the same calories as fresh fruit in a much smaller volume. Just one dried apricot contains about 10 calories!

Again, I want to stress that these are only suggestions of high-calorie foods that do not contain the top 8 allergens. Every child’s allergies are unique so always check with your child’s healthcare professional if you are unsure whether or not a food is appropriate for your child.

Do you have any tips on boosting calories or high-calorie snack ideas to share? What has helped your child to gain weight?


[i] Rabinowitz S.S. et al. (n.d.). Nutritional Considerations in Failure to Thrive. Retrieved from:

[ii] KidsHealth from Nemours. (n.d.). Failure to Thrive. Retrieved from:

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Food Allergy Living is a resource for parents of children with food allergies, brought to you by Nutricia, the makers of Neocate. For more in-depth information about our purpose & authors, see our About Food Allergy Living page.