Relationships between human thirst, hunger, drinking, and feeding.

Area of Science:

• Physiology
• Nutrition Science
• Behavioral Science

Background:

• Traditional views link hunger to eating and thirst to drinking for energy and hydration balance.
• Modern food environments with energy-dense, low-satiety options challenge these homeostatic mechanisms.
• Changes in food composition and consumption patterns raise questions about energy balance regulation.

Purpose of the Study:

• To investigate if altered food composition and eating patterns disrupt the hunger-thirst-drinking-eating relationship.
• To explore the potential for these disruptions to lead to positive energy balance.
• To examine the predictive power of hunger and thirst on energy intake.

Main Methods:

• Review of published evidence and findings from a 7-day observational study.
• Collection of hourly appetitive ratings and dietary recalls from 50 adults.
• Analysis of fluid intake timing and beverage composition in relation to eating occasions.

Main Results:

• Hunger exhibits a bimodal daily pattern, while thirst is more stable and pronounced.
• Approximately 75% of fluid intake occurs around meals, primarily from energy-yielding beverages.
• Neither hunger nor thirst levels strongly predict energy intake; stable thirst may drive drinking, potentially promoting positive energy balance with available beverages.

Conclusions:

• Current hunger and thirst signals may not be reliable predictors of energy intake in the context of modern diets.
• The interplay of stable thirst, increased availability of energy-dense beverages, and low satiety may disrupt energy balance.
• Individual variations in hunger and thirst require further investigation regarding their impact on energy balance.