Although anchoring effects have been considered highly robust and pervasive in decision-making, the theory of anchoring and adjustment has been rarely applied in studying comparative advertising or health claims. This dissertation fills the gap by examining the effects of brand anchoring on people's nutritiousness perception, attitudes toward the ad, attitudes toward the brand, and purchase intention. It also examines whether different scales (percentage vs. fraction) on which a nutritional attribute is expressed has any advertising effect. Furthermore, this dissertation extends the investigation into the possible moderating roles of personal involvement, health consciousness, and product experience in anchoring procedures. In order to examine the anchoring effect in comparative nutrition claims, a 2 (without anchor brand vs. with anchor brand) × 2 (expanded scale vs. contracted scale) × 2 (products) mixed-factorial experiment was carried out. Data were collected from 304 students recruited from a business school at a Western university. Findings revealed significant differences across anchoring conditions for the granola bar ad, but not for the chocolate ad, which supported the case-by-case approach adopted by the FTC in regulating health claims and warranted future studies on additional product categories. Results also showed that using an anchor brand or an expanded scale to describe nutrition content resulted in an inflated perception of product benefits and more favorable attitudes toward the ad. This dissertation offers insight into the effectiveness of using comparative nutrition claims to attract consumers and the importance of developing remedies to protect consumers from confusing claims. Furthermore, the research results are consistent with existing anchoring research suggesting that an anchoring process is generally not moderated by traditionally recognized moderating factors in comparative advertising research, including personal involvement, health consciousness, and product experience. The theoretical implications and practical applications of the research findings are finally discussed.