Physiology& Behavior,Vol. 48, pp. 633-636. ~ PergamonPress plc, 1990. Printedin the U.S.A.
0031-9384/90$3.00 + .00
Sensory Evaluations of Fat-Sucrose and Fat-Salt Mixtures: Relationship to Age and Weight Status I Z O E S. W A R W I C K A N D S U S A N S. S C H I F F M A N 2
Departments o f Psychology and Psychiatry, Duke University, Durham, N C 27706 Received 16 July 1990
WARWICK, Z. S. AND S. S. SCHIFFMAN. Sensory evaluations of fat-sucrose and fat-salt mixtures: Relationship to age and weight status. PHYSIOL BEHAV 48(5) 633-636, 1990.--Young (mean age 22.4 years) and elderly (mean age 82.3 years) subjects tasted and rated a range of liquids containing between 0.5% and 36% dairy fat by weight. The liquids also contained either sucrose (0-20%) or NaC1 (0-0.584%). Within each age group both normal weight and overweight subjects participated. The fat content in the mixtures was unrelated to pleasantness ratings for elderly subjects. The concentrations of both fat and sucrose in the mixtures determined the hedonic responses of young normal weight subjects. Overweight young subjects' hedonic responses were predominantly influenced by sucrose concentration. Fat content in dairy-salt mixtures was significantly related to pleasantness ratings by young subjects, but did not influence ratings by elderly subjects. These findings suggest that the elderly can significantly reduce dietary fat intake without sacrificing perceived pleasantness. Fat-sucrose mixtures
Fat-salt mixtures
Taste and aging
evaluated mixtures of salt and dairy fat.
HIGH-FAT liquids are perceived as relatively unpleasant when tasted on their own; however, they become more palatable when combined with sucrose (1,2). Solid fat-rich stimuli also increase in pleasantness when sucrose is added (3). Foods that are high in fat and sucrose generally promote overeating in both humans (5,6) and rats (7, 9, 10). Excess weight gain often occurs when the rise in caloric intake is not offset by an equivalent increase in energy expenditure. A relationship between body weight and preferred fat level has been found for mixtures of fat and sucrose that contain 0.5% to 52% fat by weight (1). Obese subjects preferred higher levels of fat in the fat-sucrose mixtures relative to normal weight persons. A mathematical algorithm known as the Response Surface Method was used to estimate the level of sucrose and fat in the optimally preferred mixture. The average optimally preferred fat level among subjects in the obese group was 34% (with 4% added sucrose) while the normal weight group had a predicted hedonic optimum of 21% fat and 8% sucrose. Subjects currently at an appropriate weight-for-height but having a history of obesity also preferred a higher level of fat than never-obese subjects. The purpose of the present study was to determine if aging affects patterns of preference for liquids containing fat. Elderly and young subjects, both normal weight and overweight, evaluated a range of fat-sucrose mixtures. In addition, all subjects
METHOD
Subjects Four groups of subjects (10 per group) participated in this study: young normal weight, young overweight, elderly normal weight and elderly overweight. The criterion for overweight was at least 15% greater than ideal weight-for-height norms as published in the 1983 Metropolitan Life Insurance Tables. Young subjects were Duke University students and employees with an average age of 22.4 years (s.d. 3.2). Elderly subjects were healthy residents of the Methodist Retirement Home, Durham, NC; the average age of this group was 82.3 years (s.d. 6.4).
Stimuli Sucrose and NaC1 were added to four dairy products that contained fat at the following levels by weight: 0.5% (skim milk), 3.5% (whole milk), 11.5% (half-and-half) and 36% (heavy cream). Sixteen fat-sucrose samples were prepared by combining (wt./wt.) each of the four dairy liquids with 0%, 5%, 10% or 20% reagent-grade sucrose (Table 1). Sixteen fat-salt mixtures were obtained by combining (wt./wt.) each of the dairy liquids with 0%,
1Supported by NIA Grant AG00043 to Susan S. Schiffman. 2Requests for reprints should be addressed to Susan Schiffman, Department of Psychology, Duke University, Durham, NC 27706.
633
634
WARWICK AND SCHIFFMAN
TABLE 1 COMPOSITIONOF FAT-SUCROSEAND FAT-SALTMIXTURES Fat Source
Fat Content (% wt./wt.)
Added Sucrose (% wt./wt.)
5% SUCROSE
0% SUCROSE
10% SUCROSE
20%
SUCROSE
O--Oy0o~£ notmGI wei@hl
Added NaCI (% wt./wt.)
O--•youn 9 overwenghl 7~ 1
Skim milk Whole milk Half and half Heavy cream
0031-9384/90$3.00 + .00
Sensory Evaluations of Fat-Sucrose and Fat-Salt Mixtures: Relationship to Age and Weight Status I Z O E S. W A R W I C K A N D S U S A N S. S C H I F F M A N 2
Departments o f Psychology and Psychiatry, Duke University, Durham, N C 27706 Received 16 July 1990
WARWICK, Z. S. AND S. S. SCHIFFMAN. Sensory evaluations of fat-sucrose and fat-salt mixtures: Relationship to age and weight status. PHYSIOL BEHAV 48(5) 633-636, 1990.--Young (mean age 22.4 years) and elderly (mean age 82.3 years) subjects tasted and rated a range of liquids containing between 0.5% and 36% dairy fat by weight. The liquids also contained either sucrose (0-20%) or NaC1 (0-0.584%). Within each age group both normal weight and overweight subjects participated. The fat content in the mixtures was unrelated to pleasantness ratings for elderly subjects. The concentrations of both fat and sucrose in the mixtures determined the hedonic responses of young normal weight subjects. Overweight young subjects' hedonic responses were predominantly influenced by sucrose concentration. Fat content in dairy-salt mixtures was significantly related to pleasantness ratings by young subjects, but did not influence ratings by elderly subjects. These findings suggest that the elderly can significantly reduce dietary fat intake without sacrificing perceived pleasantness. Fat-sucrose mixtures
Fat-salt mixtures
Taste and aging
evaluated mixtures of salt and dairy fat.
HIGH-FAT liquids are perceived as relatively unpleasant when tasted on their own; however, they become more palatable when combined with sucrose (1,2). Solid fat-rich stimuli also increase in pleasantness when sucrose is added (3). Foods that are high in fat and sucrose generally promote overeating in both humans (5,6) and rats (7, 9, 10). Excess weight gain often occurs when the rise in caloric intake is not offset by an equivalent increase in energy expenditure. A relationship between body weight and preferred fat level has been found for mixtures of fat and sucrose that contain 0.5% to 52% fat by weight (1). Obese subjects preferred higher levels of fat in the fat-sucrose mixtures relative to normal weight persons. A mathematical algorithm known as the Response Surface Method was used to estimate the level of sucrose and fat in the optimally preferred mixture. The average optimally preferred fat level among subjects in the obese group was 34% (with 4% added sucrose) while the normal weight group had a predicted hedonic optimum of 21% fat and 8% sucrose. Subjects currently at an appropriate weight-for-height but having a history of obesity also preferred a higher level of fat than never-obese subjects. The purpose of the present study was to determine if aging affects patterns of preference for liquids containing fat. Elderly and young subjects, both normal weight and overweight, evaluated a range of fat-sucrose mixtures. In addition, all subjects
METHOD
Subjects Four groups of subjects (10 per group) participated in this study: young normal weight, young overweight, elderly normal weight and elderly overweight. The criterion for overweight was at least 15% greater than ideal weight-for-height norms as published in the 1983 Metropolitan Life Insurance Tables. Young subjects were Duke University students and employees with an average age of 22.4 years (s.d. 3.2). Elderly subjects were healthy residents of the Methodist Retirement Home, Durham, NC; the average age of this group was 82.3 years (s.d. 6.4).
Stimuli Sucrose and NaC1 were added to four dairy products that contained fat at the following levels by weight: 0.5% (skim milk), 3.5% (whole milk), 11.5% (half-and-half) and 36% (heavy cream). Sixteen fat-sucrose samples were prepared by combining (wt./wt.) each of the four dairy liquids with 0%, 5%, 10% or 20% reagent-grade sucrose (Table 1). Sixteen fat-salt mixtures were obtained by combining (wt./wt.) each of the dairy liquids with 0%,
1Supported by NIA Grant AG00043 to Susan S. Schiffman. 2Requests for reprints should be addressed to Susan Schiffman, Department of Psychology, Duke University, Durham, NC 27706.
633
634
WARWICK AND SCHIFFMAN
TABLE 1 COMPOSITIONOF FAT-SUCROSEAND FAT-SALTMIXTURES Fat Source
Fat Content (% wt./wt.)
Added Sucrose (% wt./wt.)
5% SUCROSE
0% SUCROSE
10% SUCROSE
20%
SUCROSE
O--Oy0o~£ notmGI wei@hl
Added NaCI (% wt./wt.)
O--•youn 9 overwenghl 7~ 1
Skim milk Whole milk Half and half Heavy cream
