Soy Addition to Soft Pretzels Led to Greater Sensory-Specific Satiety in Inactive and Active Individuals

Abstract

Abstract Objectives Protein and fiber have both been shown to modulate satiety sensations and food intake. Soft pretzels were formulated to contain soy ingredients high in both protein and fiber. Therefore, we hypothesized that soy substitution in soft pretzels would increase sensory-specific satiety following consumption. Additional objectives of this study were to determine if physical activity or previous protein supplement intake influenced satiety sensations. Methods Traditional and soy soft pretzels were produced to be isocaloric (1255 KJ or 300 Kcal/serving), equal in lipid content (6 g/serving), and similar in size and color. Soy pretzels were higher in protein and fiber due to the inclusion of soy flour, soymilk powder, and wheat gluten. Satiety was measured following consumption of both pretzel types using a randomized and balanced cross-over design (n = 51 subjects). Ten-centimeter visual analogue scales were used to measure hunger, desire to eat, how much they could eat, and thoughts of food before and after consumption as well as over time (every 30 minutes for 2 hours). Exercise frequency was recorded as days of exercise per week. Consumption of protein supplement frequency was measured using a 5-point scale. Satiety was examined using the area under the curve (AUC) of hunger, desire to eat, how much could they eat and thoughts of food ratings, normalized by the basal values. Results The AUC for hunger was approximately 32% greater after consumption of the soy pretzels as compared to traditional wheat pretzels (P = 0.0313), indicating greater satiety. The AUCs for desire to eat and how much subjects could eat were 34% (P = 0.0133) and 33% (P = 0.0320) greater in soy pretzels, respectively. The AUCs for thoughts of food did not differ between samples (P = 0.1808). Frequency of high protein supplement consumption and exercise frequency did not impact any satiety measurement in either sample or the difference between the samples. Conclusions Together these data suggest that consumption of the soy pretzels lead to greater satiety and reduced desire to eat, possibly due to the higher protein and fiber content. Satiation was not measured in this group; however, the higher satiety values could have implications on food intake subsequent to soy pretzel consumption. Funding Sources This study was supported by the Ohio Soybean Council.