When children receive bone marrow transplants to treat serious blood diseases, doctors need to figure out how much nutrition they need. This study of 12 children found that during the most intense treatment phase, kids actually needed fewer calories than standard formulas suggested. However, many children still weren’t getting enough food to meet even these lower needs. The findings suggest doctors should measure each child’s actual energy needs rather than using one-size-fits-all calculations, and make sure kids are getting proper nutrition support during this critical time.

The Quick Take

  • What they studied: How many calories children actually need during and after bone marrow transplants, compared to what doctors usually calculate
  • Who participated: 12 children (9 boys and 3 girls) receiving bone marrow transplants—some being treated for blood cancers and others for non-cancer blood diseases
  • Key finding: During the toughest week of treatment (days 7-14 after transplant), children needed about 10% fewer calories than standard formulas predicted. Despite this, many kids still weren’t eating enough to meet even these lower needs.
  • What it means for you: If your child is getting a bone marrow transplant, doctors should measure their actual calorie needs rather than using general formulas. This personalized approach may help prevent both overfeeding and underfeeding during recovery.

The Research Details

Researchers followed 12 children receiving bone marrow transplants and measured how many calories their bodies actually burned at different stages of treatment. They used a special machine called indirect calorimetry that measures energy use by analyzing breathing patterns—similar to how a fitness tracker estimates calories burned, but much more precise. Measurements were taken before treatment started, on transplant day, and at several points during recovery up to 90 days later.

The researchers compared these actual measurements to what standard formulas (called the Oxford Equation) predicted the children should need. They also tracked how much food and nutrition the children actually received through eating, feeding tubes, and IV fluids. Most measurements were done while children were fasting, though some had to be done shortly after eating due to medical needs.

Bone marrow transplants involve intense chemotherapy and sometimes full-body radiation that can dramatically change how a child’s body works. Doctors previously assumed these treatments would increase calorie needs, but this study shows the reality is more complicated. Getting nutrition exactly right is critical—too little food slows healing, but too much can cause other problems. Understanding the actual energy needs helps doctors provide better nutritional support.

This is a small study with only 12 children, so results should be viewed as preliminary findings rather than definitive answers. The study was carefully designed with standardized measurement conditions, though some measurements couldn’t follow the ideal fasting protocol due to medical needs. The researchers directly measured energy needs rather than relying on estimates, which is the gold standard approach. However, the small size means results may not apply to all children in all situations.

What the Results Show

The most striking finding occurred during days 7-14 after transplant, when children’s bodies were under the most stress from chemotherapy and radiation. At this critical time, children actually needed about 1,154 calories per day, which was roughly 10% less than the standard formula predicted (1,408 calories). This might seem like good news—less food needed—but it revealed a serious problem: the standard formula was overestimating needs during the most toxic phase of treatment.

However, even with these lower actual needs, many children weren’t getting enough food. On days 7-14, when most children (92%) were receiving nutrition through IV tubes, only half of the children were actually getting enough calories to meet their measured needs. This gap between what children needed and what they received was even worse at other time points. For example, on days 21-28, children were only getting about 19% of the calories they actually needed.

The study also showed that children’s calorie needs changed throughout the transplant process. Before transplant and immediately after, calorie needs were higher. By day 90 (three months later), when children were eating regular food again, most were finally getting enough nutrition. This pattern suggests that the early weeks after transplant are the most challenging time for meeting nutritional needs.

The research revealed important details about how nutrition was being delivered. On transplant day (day 0), before IV nutrition was started, children were only getting about 35% of their calorie needs, mostly from glucose-containing IV fluids. This showed a critical gap in nutrition support right at the beginning of treatment. As time went on and more children received IV nutrition support, coverage improved somewhat, but still fell short of actual needs in many cases. By day 90, when children could eat regular food, 7 out of 9 children were finally getting adequate nutrition.

Previous medical thinking suggested that the intense chemotherapy and radiation used in bone marrow transplants would dramatically increase children’s calorie needs. This study challenges that assumption, at least during the early toxic phase. The findings align with observations that children are often immobilized during early recovery, which can reduce energy needs. The study suggests that the relationship between treatment intensity and calorie needs is more complex than previously thought, and that individual measurement is more reliable than general formulas.

The biggest limitation is the small number of children studied (only 12), which means results may not apply to all children receiving bone marrow transplants. The study included children with different types of diseases and different transplant approaches, which could affect results. Some measurements couldn’t be done under ideal fasting conditions due to medical needs, which could slightly affect accuracy. The study was also conducted at a single medical center, so results might differ in other hospitals with different treatment protocols. Finally, the study doesn’t explain why calorie needs decreased during the toxic phase—it only documents that they did.

The Bottom Line

Based on this research, doctors should consider measuring actual calorie needs using indirect calorimetry (or similar methods) rather than relying solely on standard formulas for children undergoing bone marrow transplants. This is especially important during the first two weeks after transplant. Additionally, even when calorie needs are lower than expected, doctors should ensure children are actually receiving adequate nutrition—the study showed many children weren’t getting enough despite lower needs. Families should work closely with the transplant team’s nutrition specialists to monitor food intake and adjust nutrition support as needed. (Confidence level: Moderate—based on a small study, but with direct measurements)

This research is most relevant to children receiving bone marrow transplants and their families, as well as doctors and nutritionists caring for these children. It’s less relevant to children receiving other types of cancer treatment or those with other medical conditions, though some principles may apply. Parents of children undergoing bone marrow transplants should discuss individualized nutrition planning with their medical team rather than assuming standard recommendations apply.

Nutrition needs change throughout the transplant process. The biggest changes happen in the first two weeks after transplant, when calorie needs are lowest. By three months after transplant, when children are eating regular food, nutrition status typically improves significantly. However, some children may need ongoing nutrition support for months or even years after transplant, depending on complications and recovery progress.

Want to Apply This Research?

  • Track daily calorie intake and compare it to the target set by your child’s nutrition team. Record the percentage of target met each day (for example, ‘Met 60% of calorie goal today’). This helps identify patterns in nutrition gaps and shows whether adjustments to feeding plans are working.
  • Work with your nutrition team to set realistic daily calorie targets based on your child’s measured needs rather than general formulas. If your child isn’t meeting targets, discuss with the team whether to adjust meal timing, food choices, or nutrition support methods (like IV nutrition or feeding tubes). Track which foods or feeding methods work best for your child.
  • Monitor weekly trends in nutrition intake rather than focusing on individual days, since intake naturally varies. Set weekly goals (for example, ‘Meet 70% of calorie needs on average this week’) and adjust based on progress. Share tracking data with the nutrition team at regular appointments to guide ongoing adjustments to the nutrition plan.

This research describes findings from a small study of 12 children and should not be used to replace medical advice from your child’s transplant team. Every child’s nutritional needs during bone marrow transplant are unique and depend on many factors including age, weight, type of disease, type of transplant, and individual response to treatment. Always work with your child’s doctors and nutrition specialists to develop an individualized nutrition plan. Do not change your child’s nutrition support or feeding plan based on this research without consulting your medical team first. This information is educational and is not a substitute for professional medical advice, diagnosis, or treatment.