Energetics, adaptation, and adaptability

Area of Science:

• Human population biology
• Biological anthropology
• Energetics

Background:

• Energy capture and conversion are crucial for human survival.
• Biological anthropology utilizes energetics in population biology studies.
• Human energy expenditure varies significantly across populations.

Purpose of the Study:

• Review evidence for genetic adaptation in human energy expenditure.
• Present models for physiological adaptability to reduced energy availability.
• Explore mechanisms linking negative energy balance to reproductive function.

Main Methods:

• Review of existing literature on human energetics and adaptation.
• Analysis of genetic components in energy expenditure (basal metabolic rate, physical activity, etc.).
• Examination of metabolic adaptation to low energy intakes.

Main Results:

• Genetic factors influence basal metabolic rate, physical activity, and thermic effect of food.
• Metabolic adaptation to low energy intake is observed in diverse populations.
• Negative energy balance is linked to reduced reproductive function in women.

Conclusions:

• Thyroid hormones play a role in energy metabolic responses to low energy availability.
• A model is proposed linking energy availability to physical activity and maintenance metabolism.
• Reduced energy availability may affect ovulation via aspartate levels and sympathetic nervous system activity.