Display Settings:

Format

Send to:

Choose Destination
Am J Clin Nutr. 2011 Jul;94(1):66-74. doi: 10.3945/ajcn.111.014399. Epub 2011 May 11.

Estimating changes in free-living energy intake and its confidence interval.

Author information

  • 1Laboratory of Biological Modeling, National Institute of Diabetes and Digestive and Kidney Diseases, Bethesda, MD 20892, USA. kevinh@niddk.nih.gov

Abstract

BACKGROUND:

Free-living energy intake in humans is notoriously difficult to measure but is required to properly assess outpatient weight-control interventions.

OBJECTIVE:

Our objective was to develop a simple methodology that uses longitudinal body weight measurements to estimate changes in energy intake and its 95% CI in individual subjects.

DESIGN:

We showed how an energy balance equation with 2 parameters can be derived from any mathematical model of human metabolism. We solved the energy balance equation for changes in free-living energy intake as a function of body weight and its rate of change. We tested the predicted changes in energy intake by using weight-loss data from controlled inpatient feeding studies as well as simulated free-living data from a group of "virtual study subjects" that included realistic fluctuations in body water and day-to-day variations in energy intake.

RESULTS:

Our method accurately predicted individual energy intake changes with the use of weight-loss data from controlled inpatient feeding experiments. By applying the method to our simulated free-living virtual study subjects, we showed that daily weight measurements over periods >28 d were required to obtain accurate estimates of energy intake change with a 95% CI of <300 kcal/d. These estimates were relatively insensitive to initial body composition or physical activity level.

CONCLUSIONS:

Frequent measurements of body weight over extended time periods are required to precisely estimate changes in energy intake in free-living individuals. Such measurements are feasible, relatively inexpensive, and can be used to estimate diet adherence during clinical weight-management programs.

Comment in

PMID:
21562087
[PubMed - indexed for MEDLINE]
PMCID:
PMC3127505
Free PMC Article

Images from this publication.See all images (6)Free text

FIGURE 1.
FIGURE 2.
FIGURE 3.
FIGURE 4.
FIGURE 5.
FIGURE 6.
PubMed Commons home

PubMed Commons

0 comments
How to join PubMed Commons

    Supplemental Content

    Full text links

    Icon for HighWire Icon for PubMed Central
    Loading ...
    Write to the Help Desk