Why liquid energy results in overconsumption

Abstract

Liquids have been shown to have a low satiating efficiency. The may be related to the high rate of consumption for liquids which may be higher than 200 g/min. In a number of studies, we showed that the positive relationship between eating rate and energy intake is mediated by oro-sensory exposure time. Longer sensory exposure times are consistently associated with lower food intakes. This observation maybe linked to the role of cephalic phase responses to foods. Cephalic phase responses are a set of physiological responses, which are conceived to prepare the digestive system for the incoming flow of nutrients after ingestion, with the aim of maintaining homeostasis. Results from various studies suggest that cephalic phase responses are much smaller (absent) for liquids compared to solids. It is hypothesised that the absence of cephalic phase responses to liquid foods may be one of the causes why liquid energies enter the body undetected and lead to weak energy intake compensation. This idea fits with the concept of the taste system as a nutrient-sensing system that informs the brain and the gastro-intestinal system about what is coming into our body. With liquids, this system is bypassed. Slower eating may help the human body to associate the sensory signals from food with their metabolic consequences. Foods that are eaten quickly may impair this association, and may therefore lead to overconsumption of energy, and ultimately to weight gain. Appetite: Liquid energy: Obesity: Energy intakeIn the last few decades it has become clear that the high prevalence of obesity in developing countries is a normal behavioural response to an abnormal obesogenic environment. This obesogenic environment facilitates food (energy) intake and limits energy expenditure. Recent evidence suggests that changes in energy intake are the dominant factors in increasing prevalence of obesity since the 1980s (1,2) . Frequent exposure to food cues, large portion sizes, large available variety, high energy density and high palatability of foods are implicated in this respect (3) . This paper focuses on one additional element of our food supply and our eating environment, i.e. the high eating rate at which we can ingest a vast majority of foods in our current food supply. It is hypothesised that the high eating rate undermines our body's capacity to regulate energy intake at healthy levels. This may work by impairing the congruent relationship between sensory input and metabolic consequences. The physiological background for this may be that foods that are consumed quickly like liquids do not lead to functional cephalic phase responses (CPR). CPR are the predominantly learned physiological responses to the sensory signals from food. Before focusing on the role of eating rate in the regulation of food intake, we first discuss a simple psycho-biological model of eating behaviour that helps to explain the later reasoning in this paper.Sensory and metabolic signals involved in eating behaviour Fig. 1 illustrates how eating behaviour is guided by s...

Discretionary food and beverage consumption and its association with demographic characteristics, weight status, and fruit and vegetable intakes in Australian adults

“…Consistent evidence suggests that energycontaining beverages are more strongly associated with obesity compared with solid foods (13,14,34) . One explanation may be the comparably rapid ingestion rate of liquid, which leads to a weaker physiological sensory response than for solid food (35) . Hence, consumption of discretionary beverages results in lower satiety than consumption of foods (36)(37)(38)(39) , leading to overconsumption (35) and substantial increases in energy intake (11,40,41) .…”

“…One explanation may be the comparably rapid ingestion rate of liquid, which leads to a weaker physiological sensory response than for solid food (35) . Hence, consumption of discretionary beverages results in lower satiety than consumption of foods (36)(37)(38)(39) , leading to overconsumption (35) and substantial increases in energy intake (11,40,41) . Higher fruit and vegetable intakes were independently associated with lower discretionary food/beverage consumption.…”

“…In the present study, data obtained from 7873 adults (19 years or above) with at least one 24 h dietary recall and weight and height measured were used for analyses, with the results weighted to reflect the Australian population (5)(6)(7) . Age groups were based on the NNPAS age categories (19)(20)(21)(22)(23)(24)(25)(26)(27)(28)(29)(30)(31)(32)(33)(34)(35)(36)(37)(38)(39)(40)(41)(42)(43)(44)(45)(46)(47)(48)(49)(50), 51-70 and 70+ years) and socio-economic quintiles were based on the Socio-Economic Index of Disadvantage for Areas (SEIFA), where the first SEIFA quintile indicates the most disadvantaged areas (5) . Country of birth was classified according to whether the respondents were born in Australia, English-speaking countries, or others.…”

Effects of chewing on appetite, food intake and gut hormones: A systematic review and meta-analysis

“…Foods and beverages that can be consumed quickly are associated with overconsumption since the speed of eating bypasses the usual "oral metering" which is necessary for the full expression of satiation and satiety [17]. This is attributed to insufficient mastication and/or to reduced levels of oro-sensory signaling during eating, leading to limited cephalic-phase responses and delayed onset of satiety.…”

Potential benefits of satiety to the consumer: scientific considerations

“…By contrast, habitual consumption of sweet drinks, particularly of low-energy 'diet' versions, may rely partly on reinforcement through slating of thirst (59) , or pharmacologically via caffeine, or even by pairing with other energy intake, rather than substantive satiation (60) . Nevertheless, sweetness appears to retain a high hedonic value (even without energy) and is a strong reinforcer for the acceptance of flavours paired with it, provided that hunger is present (61) .…”