U.S. Department of Health and Human Services

Body Weight Simulator

The Body Weight Simulator, developed by Dr. Kevin Hall’s research group, is an online tool designed for obesity researchers and weight management professionals to better understand how diet and exercise quantitatively contribute to weight loss and weight loss maintenance.
This information is for use in adults only and is not intended to provide personal medical advice.   NIDDK cannot provide a diagnosis or medical advice for an individual situation.  A health care provider who has examined you and knows your medical history is the best person to provide that information.  If you have specific questions about the information presented, concerns about individual health matters or body weight management, please consult your physician.
The Body Weight Simulator was published as part of The Lancet Series on Obesity.  Please reference this paper when publishing material using the Body Weight Simulator:
Hall KD, Sacks G, Chandramohan D, Chow CC, Wang YC, Gortmaker SL, Swinburn BA. Quantification of the effect of energy imbalance on bodyweight. Lancet. 2011 Aug 27;378(9793):826-37. (PMID:21872751)
Full description of the model equations can be found in the pdf iconDynamic Mathematical Model of Body Weight Change in Adults (PDF, 244 KB) document.
View our brief introductory video about the body weight simulator.  To optimize viewing, your media player should be set to high resolution and the video should be viewed in full screen mode. (Length 02:00)

​Bodyweight Simulator Application

The simulator requires the most recent version of Java to run correctly.  If you cannot see the “Start Simulator” button below, please download the free installer.


Requirements for Running the Simulator

The first time the simulator is launched on your computer, your web browser will request that the applet be given access to your computer. This is required so that simulation results can be cut and pasted from the tabulated data.

The simulator requires that Java is installed to run. Please download the free installer.

Some users may find that Java has been disabled and the simulator will not run. Instructions for enabling Java can be found on the Java website.

If you are using Chrome versions 42 and higher, an additional configuration step is required:

  1. In your URL bar, enter chrome://flags/#enable-npapi
  2. Click the Enable link for the Enable NPAPI configuration option
  3. Click the Relaunch button that now appears at the bottom of the configuration page

Accessibility and Section 508 Compliance

The National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK) and the NIH Office for Intramural Research are committed to providing access to all individuals - disabled or not - who are seeking information from their programs. To provide this information, the Body Weight Simulator has been designed to conform to Section 508 of the Rehabilitation Act (as amended). Section 508 requires that all individuals with disabilities (whether they are federal government employees or members of the general public) have access to and use of information and data comparable to that provided to individuals without disabilities, unless an undue burden would be imposed. This website has been designed and tested for Section 508 conformance and accessibility, while acknowledging that both may be a work-in-progress.

Persons using assistive technology may not be able to fully access graphical representations of the Body Weight Simulator. However, all data is available and accessible in its raw form.

Any individual using assistive technology (such as a screen reader, Braille reader, speech recognition software, etc.) who experiences difficulty in accessing information on this site should contact Dr. Kevin Hall (NIDDK), placing "Accessibility/Section 508 Conformance" in the subject line. The nature of the accessibility problem and contact information should be included in any e-mail message. If the accessibility problem involves a particular Web page, including the URL (Web address) of the page would be helpful. A member of the Laboratory of Biological Modeling - (LBM) staff will contact individuals with accessibility problems as soon as possible to assist them and to provide them the information sought.

For More Information

If you find that you are still unable to run the Body Weight Simulator, please send an email to Dr. Kevin Hall (NIDDK) and indicate whether you are using a PC or a MAC, what operating system and version, and which browser and version, and the nature of the problem(s) you encountered. ​