Best practices for including sex as a variable in appetite research

Area of Science:

• Reproductive biology
• Neuroscience
• Behavioral science

Background:

• Sex is increasingly recognized as a critical variable in appetite research.
• Many studies overlook sex differences or fail to account for reproductive physiology.
• Inconsistent inclusion of both sexes and inadequate analysis of sex-specific outcomes limit current research.

Purpose of the Study:

• To promote the inclusion of sex as a variable in appetite research.
• To highlight known sex differences in healthy and disordered eating patterns.
• To provide methodological recommendations for incorporating sex into study designs.

Main Methods:

• Reviewing existing literature on sex differences in appetite and eating behaviors.
• Illustrating sex-specific variations across the lifespan, including puberty, reproductive adulthood, and senescence.
• Discussing the impact of the hypothalamic-pituitary-gonadal (HPG) axis and menstrual cycle on appetite.
• Outlining best practices for hormone assays, experimental design, and statistical analysis.

Main Results:

• Significant sex differences exist in appetite regulation and eating disorders.
• Hormonal fluctuations, particularly the menstrual cycle in females and changes during reproductive senescence in both sexes, influence appetite.
• Methodological challenges include accounting for the variability of the menstrual cycle and HPG axis function.

Conclusions:

• Integrating sex as a biological variable is essential for advancing appetite research.
• Standardized methodologies considering reproductive physiology will enhance rigor and replicability.
• Future research should leverage emerging technologies like wearable sensors for more comprehensive data collection.