Dietmate - A Computerized Intervention for Computer-Assisted Cholesterol Reduction.

Computer-Assisted Cholesterol Reduction

Summary of Phase I Results
Albert Jerome, Ph.D.
PICS, Inc., Reston, VA

This research was supported by SBIR grant R43 HL44260 from the National Heart, Lung, and Blood Institute. Please do not quote without permission.


The purpose of this Phase I research study was to investigate the feasibility of administering a dietary and exercise intervention for high blood cholesterol via a small hand-held microcomputer. A preliminary version of the computer was assembled prior to the Phase I project and small-scale testing of program functional integrity and consumer response to the product was conducted. During this Phase I project, we assembled a second prototype version and conducted a 12-week self-help outcome trial, the results of which are described in detail below.


Subjects. Thirty-four subjects (13 men and 21 women) ranging in age from 38 to 65 (M = 48.5) participated in the study. Subjects were recruited by newspaper ads soliciting volunteers for a cholesterol reduction research project. Subjects were predominantly Caucasian (94%) and well educated (Mean years of education = 15.8, SD = 2.3). All subjects were overweight (M = 21.4%, SD = 11.2) with a mean body mass index (BMI) = 31.4 (SD = 5.1). Ninety-one percent of subjects had lost 10 or more pounds on at least one previous diet. Mean cholesterol levels were 250.4 (SD = 28.0), 170.1 (SD = 24), and 47.4 (SD = 10.5) for total cholesterol, LDL and HDL, respectively. Prior to treatment, all subjects obtained permission from their physician to participate and had their blood cholesterol measured. Subject selection criteria were as follows: a) total cholesterol level > 200; b) Low-density lipoprotein level > 130; c) not taking medication that would affect blood cholesterol levels; and d) not suffering from any health problems that would preclude participation.

Dependent Measures. The primary dependent variables for this study were changes in total cholesterol and LDL levels from pretreatment to posttreatment. Cholesterol testing was conducted by an independent health care facility at no cost to participants. Full lipid panels were assessed at pretreatment and at end of treatment. Total cholesterol (only) was tested at mid-treatment (6 weeks). Other dependent variables included changes in weight and BMI, changes in blood pressure, resting pulse, body part circumference, ratings on the Body Satisfaction Scale (1 - 7 scale), and Beck Depression Inventory (BDI) scores.

Treatment. The treatment intervention used in this study was a second generation prototype version of a hand-held computer, currently under development by PICS, Inc., that implements a self-management diet and exercise program.

Hardware. The computer used in this study measures approximately 6 1/2" by 3 3/4" by 1" thick (with cover closed), weighs just under 1 lb., and operates on 4 AA batteries. The computer has seven operating buttons plus an on/off button and volume control, and is encased in a hard plastic shell with a cover that folds back to become a stand. The LCD display measures 3 3/4" by 1 7/8" and has two sections. The bottom section of the LCD is dot matrix type and can display graphics or text (8 lines by 32 characters per line). The top section of the LCD has 4 icons for prompting meals, exercise, weighing, and drinking water and displays for volume setting, date, and time. The computer has an 8-bit 80C88 microprocessor with 256 kilobytes ROM and a 4-bit 75305 microprocessor with 32 kilobytes RAM. In addition to the computer, a program manual, a gourmet cookbook and an instructional video were provided.

Program Operation. The computerized treatment was highly prescriptive and interactive. Behavioral principles such as goal setting, self-monitoring, stimulus control, feedback, and shaping were integrated at all levels of the program to foster changes in eating and exercise habits and to maximize user compliance. When subjects first began the program, the computer provided a tutorial of key functions and then prompted them to enter height, weight, age, sex, activity level, weight loss goals, usual mealtimes, and preferred exercises. On the basis of this information, a set of menus was individualized to a caloric level that projected gradual, steady weight loss. The menus were nutritionally balanced, meeting the recommendations of the Dietary Guidelines for Americans, 1990 (U.S. Department of Agriculture & U.S. Department of Health and Human Services, 1990), as well as those of nine other major health organizations that publish nutritional guidelines. Subjects input their weight daily and the computer made periodic changes to the menus to adjust calories up or down as needed to maintain weight loss within a safe range (approximately .5 to 1.5 lb. weekly).

The computer used visual (icons and text) and auditory prompts to remind subjects to eat, exercise, and drink water, thereby encouraging the development of stimulus control over these behaviors. In response to cues, users picked the appropriate action by highlighting an item from a list of actions and pressing a button. The computer then provided a series of screens that allowed them to make appropriate selections and record their behaviors. Following selection of a meal, the caloric content and percent calories from fat were displayed, and subjects were given the option of recording their meal or first changing item quantities or modifying the menu by substituting for specific items with nutritionally equivalent foods. Following a one-week baseline period, exercise targets were provided for a wide range of exercises selected by the user. Subjects were prompted by an icon and verbal message to exercise three times per week and the amount of exercise per session was very gradually increased up to a moderate expenditure of 300 calories per session.

The program included an extensive feedback system that provided messages at several different times: immediately following behaviors, as a summary at the end of the day, as a reminder or "to do" list in the morning, and as a summary at the end of each week. The feedback system tracked important variables such as total caloric intake, percent calories from fat, number of exercise sessions, and total calories expended exercising and categorized the history of these variables into discreet patterns. For example, the first missed exercise session following compliance with exercise would be classified as a "slip." Similarly, a variety of other patterns were defined on the basis of the frequency and timing of behaviors. Thus identified, these patterns result in the display of feedback messages that varied in frequency, phrasing, and tone. An additional source of daily feedback was provided by a summary screen--accessible at any time--that documented progress toward meeting daily goals for caloric intake, percent calories from fat, and exercise. Longer-term feedback was provided by a weekly summary and by charts and graphs that showed history of weight loss, calories expended exercising, and caloric intake.

Procedures. Following an initial telephone screen, interested subjects who met the study criteria requested permission from their physician to participate and had their blood drawn for testing at a local laboratory. After the results of the test were received, qualified subjects reported individually to our office to meet with a research assistant for a pretreatment assessment and to receive their computers. The pretreatment assessment included a questionnaire that obtained standard sociodemographic information and dieting history, a variety of physical measurements, a brief history of dieting, ratings of motivation and confidence in ability to be successful, and the Beck Depression Inventory. The treatment phase lasted 12 weeks. During this time, subjects met with a research assistant three times to be weighed, provide ratings of program satisfaction, and to have data uploaded from their computers. At the end of treatment, subjects reported for a final assessment in our laboratory.


Attrition. Six subjects (17.6%) failed to complete the study. Subjects who dropped out did not differ from those who completed the study on pretreatment cholesterol levels (total, HDL or LDL), weight, or BMI. Changes in Cholesterol. Changes in total cholesterol, LDL and HDL levels were examined by dependent measures t-tests, the results of which are summarized in table 1 below.

As can be seen by examining this table, significant changes in total cholesterol and LDL levels occurred during the 12-week treatment, while HDL levels were unchanged. The magnitude and distribution of changes in total cholesterol and LDLs can be seen more clearly by examining table 2 below.

Changes in Weight and Other Measures. Changes in weight, BMI, circumference measures, pulse, blood pressure, body satisfaction and BDI scores from pretreatment to posttreatment were also examined by dependent measures t-tests. The results of these analyses are presented below in Table 3. As can be seen from examining Table 3, significant changes were seen in both physical measures--weight; BMI; biceps, waist, and chest circumference; and resting pulse, and psychological measures--Body Satisfaction Scale and BDI--during the 12-week treatment. Ratings of Program Satisfaction and Ease of Use. Overall, subjects reported high levels of satisfaction with the program (M = 5.4, SD = 1.2 on a 1 - 7 scale) and rated it as being easy to use (M = 5.6, SD = 1.1 on a 1 - 7 scale). Table 4 below shows the distribution of satisfaction and ease of use ratings collected at end of treatment.

Summary and Conclusions

This Phase I SBIR study was designed to examine the feasibility of using a computerized, self-management diet and exercise intervention for the reduction of high blood cholesterol. Primary results of the study were significant decreases in total cholesterol and LDL levels during the 12- week intervention. Subjects also lost significant weight, which was reflected in changes in waist, chest, and biceps circumference, and experienced a significant drop in resting pulse. In addition, subjects showed an increase in overall satisfaction with their body and showed significant decreases in Beck Depression Inventory scores. Finally, subjects rated the computer as being easy to use and they reported high levels of overall satisfaction with the program. Results of structured interviews conducted with subjects at treatment end provided useful information pertaining to program modifications and enhancements that are being incorporated into a Phase II development plan. Overall, the results of this project demonstrate that a self-management diet and exercise intervention implemented via a hand-held computer is a feasible treatment option for the dietary treatment of hypercholesterolemia.


American College of Sports Medicine (1990). Position stand: The recommended quantity and quality of exercise for developing and maintaining cardiorespiratory and muscular fitness in healthy adults. Medicine and Science in Sports and Exercise, 22(2), 265-274.

U.S.Department of Agriculture & U.S. Department of Health and Human Services (1990). Nutrition and your health: Dietary guidelines for Americans. Washington: U.S. Government Printing Office.


1 Calculations of percent overweight were based on tables of suggested weights provided in the publication entitled: Nutrition and Health: Dietary Guidelines for Americans, U.S. Department of Agriculture and U.S. Department of Health and Human Services, 1990.