Study Notes on Research Report: Taste Perception and Implicit Attitude

Title: Taste perception and implicit attitude toward sweet related to body mass index and soft drink supplementation.
Authors: Francesco Sartor, Lucy F. Donaldson, David A. Markland, Helina Loveday, Matthew J. Jackson, Hans-Peter Kubis.
Affiliations: College of Health & Behavioral Sciences, Bangor University, UK; Department of Physiology and Pharmacology, University of Bristol, UK.

Increased soft drink consumption in western countries over the last 30 years (Barquera et al., 2008; Duffey & Popkin, 2007).
Caloric delivery from high-fructose corn syrup and glucose syrup increased 11.6 times (1966-2003, US).
Soft drinks provide 47% of added sugars in the US diet (Guthrie & Morton, 2000).
Factors contributing to consumption:
- Strong palatability of sweet taste (Lenoir et al., 2007).
- High energy density of soft drinks (Drewnowski & Bellisle, 2007).
- Low cost of soft drinks.
Low physical activity levels in western countries (Booth et al., 2000; Hayes et al., 2005) contribute to health issues associated with soft drink consumption.
High consumption correlates with weight gain, obesity, and increased metabolic syndrome risks (Malik et al., 2006; Dhingra et al., 2007).
Sweetness influences food choice (Glanz et al., 1998), with a positive correlation between calorie intake from sweet foods and sweet preference (Mattes & Mela, 1986).
Divergence in studies regarding the relationship between sweetness sensitivity and obesity (Bartoshuk et al., 2006).

Examine differences in sweet taste perception and implicit attitude toward sweet between normal-weight and overweight/obese adults.
Investigate the effects of soft drink consumption on sweet taste perception, explicit preference, and implicit attitudes in normal-weight subjects.

Subjects: 34 healthy young adults (14 males, 20 females), average age 22.8 ± 2.5 years, average BMI 24.7 ± 4.7.
Group allocation:
- Normal-weight (BMI 18-<25), n = 22.
- Overweight/Obese (BMI ≥ 25), n = 11.
Excluded: 1 subject (BMI < 18).

Evaluated sweet and salty taste perception:
- Sweetness: Concentrations of sucrose (0 to 2.75 log[sucrose] mol/L).
- Saltiness: Concentrations of sodium chloride (1 to 2.5 log[NaCl] mol/L).
Assessment Tool: Generalized Labeled Magnitude Scales (gLMS) used for intensity (150 mm) and pleasantness (86 mm).
Participants completed the Spielberger State and Trait Anxiety Questionnaire (1983) prior to testing.

Measures implicit attitudes and food preferences.
Used Inquisit 3.0 for data collection, employing blocks of compatible and incompatible trials with food stimuli.
Scoring computed using D-score algorithm (Greenwald et al., 2003).

Subjects: Healthy, lightly active adults, n = 12 (7 females, 5 males), average age 26 ± 6 years.
Diet diaries maintained to assess habitual intake before, during, and post-intervention.
Intervention: 1 month of soft drink supplementation (Lucozade Energy) with average intake of 760 ml/day, increasing carbohydrate intake by 2.1 ± 0.2 g/kg body weight.

Overweight/obese subjects rated sweet taste 23% less intense than normal-weight subjects.
Higher IAT scores in the overweight/obese group (2.1-fold), indicating a stronger implicit attitude toward sweet.
Correlation: Significant positive correlation between IAT scores and BMI (r = 0.36, p < 0.050).

Change in dietary composition noted during soft drink intervention, slight overall increase in energy intake.
A noted increase in sweet taste intensity and pleasantness perception post-intervention, particularly in initial sucrose-dislikers.
Leptin levels: Increased plasma leptin levels post-intervention correlated with sugar intake and preference.
Gender differences observed in taste perception, with males rating sweetness higher than females.

A relationship exists between sweet taste perception and obesity, with implicit attitudes differing between overweight and normal-weight individuals.
Chronic soft drink consumption alters taste perception and explicit preferences for sweetness.
Increased leptin levels may influence taste sensitivity, suggesting that higher leptin levels could diminish responsiveness to sweet taste.
Implicit attraction to sweet remains unchanged by short-term soft drink supplementation in normal-weight individuals.

Findings support the hypothesis linking soft drink consumption to changing taste preferences and dietary habits, potentially exacerbating obesity.
Future studies recommended to further investigate soft drink influence on taste and appetite regulation, particularly focusing on different sweetener types.