Doctors need good ways to understand what people with eating disorders are actually eating, since nutrition is so important for their health and recovery. This small study tested whether a method called “diet history”—where a trained person asks detailed questions about food—accurately measures what people eat compared to blood tests. The researchers found that diet history worked fairly well, especially when they asked about vitamins and supplements. This suggests diet history could be a helpful tool for doctors treating eating disorders, though more research with larger groups is needed to be sure.

The Quick Take

  • What they studied: Whether asking people detailed questions about their food (diet history) is an accurate way to measure what they’re eating compared to blood test results
  • Who participated: 13 adult women with eating disorders, average age 24 years, who were getting treatment at an outpatient clinic
  • Key finding: Diet history showed moderate to good agreement with blood tests for certain nutrients like iron and cholesterol, especially when people reported taking supplements. The method worked better when people were eating larger amounts of food.
  • What it means for you: If you or someone you know has an eating disorder, doctors may be able to use detailed food interviews to better understand nutrition needs. However, this is early research with a small group, so more studies are needed before making big changes to how doctors assess eating habits.

The Research Details

This was a small pilot study that looked at information already collected from 13 women with eating disorders. The researchers compared two ways of measuring what people ate: (1) a detailed interview where a trained person asks about all the foods and drinks someone consumed, and (2) blood tests that show levels of nutrients like iron and cholesterol in the body. They used statistical methods to see how well these two approaches matched up with each other. The study looked at whether the diet history method could predict what the blood tests would show.

People with eating disorders often have serious nutrition problems that can affect their health and recovery. Doctors need reliable ways to understand what their patients are actually eating so they can provide the right treatment. This study helps figure out which assessment methods work best for this specific group of patients, which is different from the general population.

This is a small pilot study, which means it’s an early exploration of an idea rather than definitive proof. The sample size of 13 people is quite small, so the results may not apply to everyone with eating disorders. The study was well-designed with appropriate statistical methods, but larger studies with more diverse groups of people are needed to confirm these findings. The fact that it was published in a peer-reviewed journal suggests it met scientific standards.

What the Results Show

The diet history method showed moderate agreement with blood tests for cholesterol and triglycerides (a type of fat in the blood). For iron, the agreement was moderate to good, especially when researchers included information about vitamin supplements people were taking. When people reported taking iron supplements, the correlation between diet history and blood iron levels was very strong (0.89 out of 1.0). The researchers also found that the diet history method worked better at estimating protein and iron intake when people were eating larger amounts of food.

The study highlighted that asking specifically about dietary supplements is very important. When researchers didn’t ask about supplements, the connection between reported iron intake and blood iron levels was weak. This suggests that people with eating disorders may rely on supplements more than the general population, and doctors need to ask about them directly.

There hasn’t been much research on which dietary assessment methods work best for people with eating disorders. Most nutrition assessment research has been done on healthy people or those with other conditions. This study is one of the first to specifically test whether diet history is valid for eating disorder patients, filling an important gap in the research.

The biggest limitation is the very small sample size of only 13 women, which means the results may not apply to everyone. The study only included women, so we don’t know if the results would be the same for men. All participants were from one clinic, so they may not represent people with eating disorders in other settings or countries. The study was a secondary analysis, meaning researchers used data that was collected for other purposes, which may have affected the quality of information available.

The Bottom Line

For healthcare providers: Diet history appears to be a reasonable method for assessing food intake in people with eating disorders, particularly when combined with direct questions about supplements (moderate confidence based on small pilot study). For patients and families: If you’re being treated for an eating disorder, be prepared to discuss not just food but also any vitamins, minerals, or other supplements you’re taking, as these significantly affect nutritional assessment.

This research is most relevant to doctors, nutritionists, and other healthcare providers who treat eating disorders. It’s also important for people with eating disorders and their families who want to understand how doctors assess nutrition. This doesn’t directly apply to people without eating disorders, as their nutrition assessment may work differently.

This is research about assessment methods, not a treatment. The findings don’t predict how quickly someone will recover, but rather help doctors get better information to guide treatment decisions. Improved assessment could lead to better-tailored nutrition support over weeks and months of treatment.

Want to Apply This Research?

  • Track daily food intake with detailed descriptions (not just calories) and specifically log all supplements, vitamins, and minerals taken. Include portion sizes and preparation methods. This mirrors the diet history method and helps identify patterns in nutrition that may need attention.
  • Use the app to create a detailed food and supplement diary that you can share with your healthcare provider. This gives doctors the same detailed information they would get from a diet history interview, helping them understand your actual nutrition intake and identify gaps.
  • Over 2-4 weeks, maintain consistent food logging with supplement tracking. Share this data with your healthcare team monthly to help them assess whether your nutrition is improving and adjust treatment as needed. Compare your logged intake with any blood work results to see patterns.

This research describes methods doctors use to assess nutrition in eating disorders—it is not a treatment guide. If you or someone you know has an eating disorder, please consult with qualified healthcare providers including doctors and registered dietitians who specialize in eating disorders. This study is a small pilot with 13 participants and should not be used to make individual medical decisions. Always discuss your specific situation with your healthcare team. Eating disorders are serious mental health conditions that require professional treatment.