Effects of L-phenylalanine on energy intake in overweight and obese women: interactions with dietary restraint status.

L-Phenylalanine (Phe), is a potent releaser of the satiety hormone, cholecystokinin (CCK) and previous studies, conducted primarily in men, show that ingestion of Phe reduces energy intake. The objective of the current study was to test the effects of Phe on energy intake in overweight and obese women. Subjects (n=32) received three treatments (high-dose (10 g Phe), low-dose (5 g Phe and 5 g glucose) or control (10 g glucose)) 20 min before an ad libitum lunch and dinner meal in a within-subjects', counterbalanced, double-blind study. No effect of Phe was found, however, interactions with dietary restraint status were detected in post-hoc analyses. Energy intake over the day was 11% lower following high-dose Phe versus control for women classified in the lower tertile of rigid restraint, a subscale of the dietary restraint scale, whereas no effects were noted for women in the middle and upper tertiles. High-dose Phe increased ratings of nausea, however, reduced energy intake in the high-dose condition was noted only for subjects with low nausea ratings. These results suggest that the satiety response to Phe is modulated by rigid restraint status and that reductions in food intake occur independently of Phe's effects on nausea.

Dimensions of everyday eating and drinking episodes.

This study sought to gain conceptual understanding of the situational nature of eating and drinking by analyzing 7 consecutive, qualitative 24-h recalls of foods and beverages consumed from 42 US adults who worked in non-managerial, non-professional positions. Participants were purposively recruited to vary in age, gender, occupation, and household composition. For each recall, participants described foods and beverages consumed, location, people present, thoughts and feelings, and activities occurring at that time. Analysis of verbatim transcripts of interviews identified 1448 eating and drinking episodes. Constant comparative analysis of participants' descriptions for episodes resulted in a conceptual framework that characterizes eating and drinking episodes as holistic and as having eight interconnected dimensions (food and drink, time, location, activities, social setting, mental processes, physical condition, recurrence). Each dimension has multiple features that can be used to describe the episodes. In recalling episodes, participants used conventional labels (e.g. "dinner") as well as modified-conventional labels (e.g. "birthday dinner") and uniquely constructed labels (e.g. "unwind time"). Labels provided insights into the dimensions of the episodes. Results suggest approaches for researchers and practitioners who seek to understand how people manage everyday eating at a time when traditional meal patterns are changing.