The Thermic Effect of Food in Energy Deficient Women

Open Access
Stockard, Sinclair T
Area of Honors:
Bachelor of Science
Document Type:
Thesis Supervisors:
  • Mary Jane De Souza, Thesis Supervisor
  • Mary Jane De Souza, Honors Advisor
  • Nancy Williams, Faculty Reader
  • energy
  • women
  • triad
  • nutrition
  • female
  • exercise
  • diet
Women suffering from anorexia nervosa, an extreme case of starvation and energy deficiency, exhibit altered metabolism in response to ingestion of a caloric load. The possibility of this phenomena has yet to be investigated in exercising women with functional hypothalamic amenorrhea (FHA), a condition which is often secondary to moderate energy deficiency. The purpose of this study was to characterize and compare the metabolic profiles of young, exercising women with either amenorrheic or eumenorrheic menstrual statuses. 7 amenorrheic (AMEN) and 9 ovulatory, eumenorrheic control (OV) women, who participated in aerobic or resistance training for at least 3 hr/wk, ingested a 700 kcal liquid mixed macronutrient meal (14% protein, 64% carbohydrate, and 22% fat) and underwent measurements of resting energy expenditure (REE), thermic effect of food (TEF), and respiratory quotient (RQ) by indirect calorimetry over a 6 hour period. Paired t-tests were used to compare REE measurements and TEF area under the curve (AUC). Two-way (group*time) repeated measures ANOVA were conducted to assess differences in absolute TEF (kcal/day), relative TEF (kcal/kgFFM/day), and RQ. Groups did not significantly differ in age, height, body mass, gynecological age, body fat percentage, fat mass, fat free mass, or lean body mass. BMI was different between the groups, where the OV group had a significantly higher BMI than the AMEN group (p=0.024). There were no significant differences between groups for ratio of measured REE to Harris-Benedict predicted REE (p=0.448) or TEF AUC (p=0.692). There were no significant (p>0.05) interaction or main effects for absolute (kcal/day) REE or relative (kcal/kgFFM/day) REE. There was no significant interaction or main effect for group with respect to RQ (p>0.05), but there was a significant main effect for time (p=0.006) with RQ significantly increasing from rest 15 minutes postprandially. These results suggest that metabolic adjustments, such as elevated TEF and a higher postprandial reliance on carbohydrate, typically seen in anorexia nervosa are not present in less severe cases of energy deficiency. However, future research is required to more thoroughly assess energetic status.