Liverpool Obesity Research Network (LORN)

The University Eating Monitor

The Universal Eating Monitor (UEM) is an automated method to measure food intake and subjective ratings of hunger, fullness and palatability during a meal.  The UEM protocol has been developed by Psychology and Clinical Sciences to provide an early assessment of the efficacy of appetite supressing potential anti-obesity drugs, with the aim of preventing drugs with little effect on appetite or undetected behavioural side effects entering large scale clinical trials.  Our UEM equipment is currently supported by software developed jointly with the University of Sussex.

What is a UEM?

UEM's have been in existence in various forms for near 30 years and operate usings specialised equipment and software.

Examining within-meal eating rate has been useful in the study of the effects of drugs on eating behaviour.  Within-meal changes in eating rate also have a long history of use in defining eating behaviour.  Decelerating cumulative intake curves associated with the normal biological development of satiety are often absent in the obese.

Whilst the macro-structural measures of eating behaviour such as total intake of individual food items potentially require little automation to record data, the measuring of minute by minute changes in human feeding behaviour is far more methodologically challenging.

The UEM consists of a set of hidden scales connected to a digital computer.  Via these scales the computer measures the weight of the plate at regular intervals as the participant consumes their meal. UEMs thus generate eating curves (intake (g) against time (min)), which can be defined as decelerating or accelerating based on the coefficient of the curves.  

In addition to this direct measure of intake, within-meal ratings of appetite (hunger, fullness and palatability) can be taken at fixed intervals during the same meal. Measuring changes in appetite ratings during the meal may be particularly important in assessing the effects of hormones and drugs. These ratings can potentially distinguish drugs known to effect palatability rather than satiety.


The UEM has been developed at the University of Liverpool to examine the effects of potential anti-obesity drugs on appetite expression.  Using within-meal appetite ratings we have successfully characterised the effects of sibutramine on satiation (as opposed to satiety) for the first time. 

Using current macrostructural approaches (meal intake and between meal ratings of appetite), reductions in intake are often seen without corresponding changes in hunger etc. Indeed, significant changes in appetite need not be expected after an ad libitum meal (where initial adjustments in appetite are compensated for by alterations in caloric intake).  This means that although reduced food intake is demonstrated, the data may yield little obvious reason why. The intimate relationship between meal size and appetite ratings is why we measure these within a meal.


The UEM has been validated in a placebo controlled, cross-over design, double blinded study in obese female volunteers (n=30, BMI 34.6 ± 3.3 kg/m2, age 46.0 ± 12.9 years: Journal of Psychopharmacology 2010; 24; 99).

The placebo, 10 mg or 15 mg of sibutramine once daily were given for seven days and then the impact of treatment on energy intake, appetite and energy expenditure was assessed using the UEM and indirect calorimetry on day 7.


Sibutramine 10 mg and 15 mg reduced food intake by 16.6 and 22.3% respectively (p

Sibutramine 10 mg significantly reduced hunger later in the meal (p

These results provide evidence that decreased consumption of a test meal induced by sibutramine is primarily due to reduced eating rate, enhancing the deceleration in cumulative food intake within a meal associated with the development of satiety. 

Changes in within-meal appetite ratings may provide key indices for assessing the therapeutic potential of novel anti-obesity drugs.  The UEM sibutramine data suggest that within-meal Visual Analogue Scales (VAS) are the most useful indices for picking up the satiating effects of drugs (also better than macrostructural measures such as VAS before or after the meal).

In addition, a significant reduction in respiratory quotient was observed.

UEM Team  

  • Dr Emma Boyland
  • Professor Jason Halford
  • Dr Joanne Harrold
  • Professor Tim Kirkham
  • Professor John Wilding
  • Professor John Blundell (external advisor)
  • Dr Terence Dovey (external collaborator)

Current UEM system

A UEM comprises of two elements, the equipment and the software.

The current UEM software is the Sussex Ingestion Pattern Monitor (SIPM).  This is owned by and used under license from the University of Sussex.  An earlier MAC based version was used in the sibutramine study.

The University of Liverpool is now running the latest PC version of the SPIM.  The University of Liverpool has also recently acquired both academic and commercial licenses for its use.

The SIPM is the only system (both MAC and PC versions) with a fully automated and integrated system to measure changes in cumulative intake, appetite (satiety, palatability and other motivational indices) and mood during a meal. Download PDF of the SIPM system.