Thirst-drinking, hunger-eating; tight coupling?

Abstract

Although thirst and hunger have historically motivated drinking and feeding, respectively, the high and increasing consumption of energy-yielding beverages and energy-diluted foods may have degraded the predictive value of these sensations on ingestive behavior. Our within subject (ie, multiple responses from the same individuals), observational (ie, free-living, with no intervention) study explored the relationships between thirst, hunger, eating, and drinking patterns in 50 weight-stable adults (39 women and 11 men aged 30+/-11 years with body mass index 26.3+/-5.9). Twenty-four-hour dietary recalls were obtained for a consecutive 7-day period. Appetite ratings were recorded hourly, over the same time period, and correlated with hourly energy and fluid intake from food and beverages. Thirst ratings were not correlated with drinking (r=0.03) or energy intake (r=0.08) during the same hour over the 7-day period. Hunger ratings were significantly, albeit moderately, correlated with energy intake (r=0.30) (P<0.05), but not with drinking (r=0.04). On average, 75% of total fluid intake was consumed during periprandial events. Further, energy-yielding beverages were the main contributor to fluid intake during both periprandial and drink-only events. These data fail to reveal associations between either thirst or hunger and ingestion of energy-yielding beverages, or strong associations between hunger and eating or thirst and drinking. These data raise questions about the predictive power of appetitive sensations for ingestive behavior.

Figure 1

Figure 1A and 1B: Percent contribution of beverage type to peri-prandial i.e. around meals (A) and drink-only (B) fluid intake, according to gender (males vs. females), BMI (normal weight vs. overweight, including obese) and age (less than 30y vs. greater than 30y).

Figure 2

Figure 2A and 2B: Correlation between thirst and total daily energy intake (A) and hunger and total daily energy intake (B) across a 7-day period, from 09:00–21:00 (n = 50).