Although modern obesogenic environments have led to a marked increase in body weight over the past few decades [1
], a large variability in weight gain among the population has been observed. Individual, environmental, biological, and genetic differences may explain this variability [2
]; however, there may be specific factors that cause certain individuals to eat beyond their energy needs and increase their susceptibility for weight gain.
Differences in appetite control have been suggested to play an important role in energy balance, eating behavior traits, and body weight [2
]. Clinical studies have observed that some individuals reported a poor relationship between their food intake and appetite sensations (e.g., hunger and fullness), suggesting that they experience a weakened satiety efficiency [6
]. This weakened postprandial inhibitory response was also highlighted in a group of individuals with obesity and who were characterized by impaired satiety signals in response to a test meal compared to a control group of individuals who had a normal weight or obesity [5
]. Although this weak satiety responsiveness, also identified as the “low satiety phenotype”, has been primarily observed in individuals with obesity, it has also been observed in those with normal body weight [6
]. This altered satiety response in some individuals has important clinical implications given that differences in satiety signaling may be involved in overeating and susceptibility to weight gain [8
In research settings, the satiety quotient (SQ), a marker of satiety responsiveness, has been used to characterize the low satiety phenotype and classify individuals according to their satiety signaling responsiveness in response to a standardized meal (i.e., individuals with low satiety responsiveness (LSR) or high satiety responsiveness (HSR)). Our previous work has shown that individuals characterized by a low SQ had higher ad libitum energy intake (as well as relative energy intake, i.e., energy intake beyond energy needs) under both experimental and free-living conditions [7
], suggesting that adults with weaker satiety responsiveness may be more vulnerable to overeating, and thus, to weight gain.
Furthermore, some studies have identified distinct psychobehavioral and biological characteristics also indicating that individuals with LSR are at a higher risk of overeating and weight gain. Accordingly, individuals characterized by a low SQ in response to a fixed meal have been associated with a greater implicit wanting for high-fat foods, a higher level of disinhibition, a lower feeling of control over food cravings [9
], a tendency to have higher levels of susceptibility for hunger triggered by external cues and night eating symptoms [10
], which are all behavior traits that have been related to overeating, obesity, and weight gain [11
]. LSR has also been associated with a tendency for greater anxiety and blunted cortisol response after a meal, suggesting a dysregulation with the hypothalamic-pituitary-adrenal (HPA) axis [10
], a condition that has been associated with obesity [14
To our knowledge, very few studies have explored how individuals with this phenotype respond to a weight loss intervention. In one previous study, no relationship between satiety responsiveness and weight loss was found [15
]. However, in a more recent study, a greater decrease in body weight and body mass index (BMI) was observed in individuals with high satiety responsiveness (HSR) compared to those with LSR, irrespective of the intervention [16
]. Since weight loss is often associated with non-optimal changes in appetite sensations [17
] and eating and psychobehavioral traits, such as an increase in cognitive restraint [18
] and even depressive symptoms [18
], it can be postulated that individuals characterized by LSR may be more resistant to weight loss and experience less optimal changes in their eating and psychobehavioral profiles when submitted to a weight loss intervention based on energy restriction. Therefore, the objective of this study was to compare the impact of an energy-restricted weight loss program on body weight loss, eating behavior traits, and psychobehavioral factors between individuals with low and high satiety responsiveness.
The literature shows large individual variability in susceptibility to weight gain and obesity as well in weight loss and/or weight regain in response to a diet-based intervention. It has been proposed that differences in baseline satiety responsiveness may explain these variations. Although similar weight loss was observed between individuals with low and high satiety responsiveness, the energy restriction was associated with less optimal changes in some, but not all, eating behavior traits in individuals expressing LSR compared to those with HSR. These results suggest that individuals with an altered satiety responsiveness, i.e., low satiety phenotype, are able to lose body weight under energy restriction, but may be at higher risk of weight regain following an energy-restricted diet.
This study confirmed that, among individuals who were overweight or obese, differences in appetite control exist, and the LSR (i.e., lower SQ) is also associated with behavioral traits associated with higher susceptibility to overeating. Accordingly, individuals with low satiety responsiveness were more susceptible to eat in response to hunger triggered by external food cues, such as the smell of food or seeing food. They also reported poor sleep quality and a tendency to have shorter sleep duration, and reported higher present-state anxiety. Most of these behavioral traits have been associated with impaired appetite control and/or weight gain [11
]. These results are concordant with our previous studies, but also with other studies showing that individuals with LSR have higher measured and reported energy intake [7
], higher levels of disinhibition, lower control over food cravings, greater wanting for high-fat foods [9
], shorter sleep duration [40
], blunted cortisol response to a meal and a tendency for higher levels of anxiety and night-eating symptoms [10
]. Moreover, this higher susceptibility to overeating was also concordant with what was observed at the buffet-type meal after the intervention, where individuals with LSR ate spontaneously more than those with HSR; yet, this was not statistically significant after adjusting for sex and BMI at this time-point. Taken together, these results suggest that individuals characterized by a low satiety efficiency are more at risk for overeating, especially in the presence of food cues.
Although individuals with low LSR had a behavioral profile that increases their risk of overeating, weight loss resistance was not observed in these individuals when submitted to an energy-restricted diet. This result does not support our hypothesis, but is concordant with a previous weight loss study based on energy restriction [15
]. Interestingly, these results are in contrast with one of our recent studies which investigated the impact of a weight loss intervention based on a highly satiating diet without a specific energy restriction in individuals with LSR or HSR [16
]. Accordingly, a lower decrease in body weight was observed in individuals with LSR compared to those with HSR irrespective of the intervention groups (i.e., control or satiating diet) [16
]. However, a significant decrease in fat mass percentage was observed in response to the satiating diet compared to control, yet this effect was similar in both satiety responsiveness groups [16
]. These different results could be explained by the fact that the weight loss intervention in the highly satiating diet study was not based on energy restriction, but only on guidelines promoting a satiating diet. Moreover, in this study, even though individuals in the LSR group had less body weight loss in response to the intervention, their satiety responsiveness (i.e., SQ) was markedly improved in the satiating diet condition compared to the HSR group [16
]. In the present study, similar changes in satiety responsiveness were observed in both HSR and LSR individuals in response to the diet intervention; yet the latter group was still considered “LSR” after weight loss. Collectively, these results suggest that the satiety responsiveness does not influence weight loss when the intervention is based on energy restriction compared to a highly satiating diet. However, the energy-restricted diet does not allow improvement of satiety efficiency in individuals who would benefit the most (i.e., the low satiety phenotype) as much as the satiating diet.
Interestingly, the results of the present study indicate that the satiety responsiveness influenced the changes in some eating behavior traits in response to an energy-restricted diet. Thus, in line with our hypothesis, individuals with LSR experienced less optimal changes in cognitive restraint and situational susceptibility to disinhibition (i.e., higher increase in cognitive restraint and some of its subscales and lower decrease in situational susceptibility to disinhibition). This is in contrast with our previous study [16
] where changes in cognitive dietary restraint, disinhibition, and susceptibility to hunger were not influenced by satiety responsiveness in the context of a non-restrictive satiating diet (or control). Since a higher level of cognitive restraint has been associated with weight gain [41
] and that disinhibition has been positively associated with poorer body-weight control [11
], these results suggest that weight loss based on energy restriction may increase susceptibility to weight regain after the intervention in individuals with LSR. The higher increase in cognitive restraint in the LSR group may also suggest that the energy-restricted diet required more pronounced cognitive or psychological effort to be implemented or be followed by individuals having LSR. In the long-term, it could also be counterproductive for appetite control and even further decrease satiety responsiveness. It is difficult to compare these results with those of other studies, since to the best of our knowledge, no other study has specifically investigated eating and psychobehavioral profiles after weight loss based on energy restriction in LSR individuals. However, based on our previous results and the present study, these findings suggest that weight loss based on energy restriction in individuals with the low satiety phenotype triggers eating behaviors that may increase their risk of overeating, weight gain, or weight loss resistance. Therefore, weight loss interventions based on non-restrictive, highly satiating diets could be more optimal for these individuals. Recently, mindfulness interventions, as well as interventions including hunger training have also been shown to produce beneficial effects on body weight loss and eating behavior traits [42
]. It is also important to note that similar changes were observed in both satiety responsiveness phenotypes for many eating behavior and psychobehavioral traits. For instance, both groups had a decrease in susceptibility to hunger as well as in food cravings as a trait. This is in line with what is generally observed in other weight loss studies based on energy restriction [20
]. These results suggest that energy restriction could also have positive outcomes on eating behavior and psychobehavioral variables, yet no other study has looked at these responses in individuals with low satiety responsiveness. Thus, future work should be designed to specifically address altered satiety responsiveness during weight loss and maintenance.
Even though these studies were not primarily designed to specifically address satiety responsiveness, the secondary analysis of different studies which have used similar weight loss interventions (i.e., energy restriction of 500 to 700 kcal/day) represents a unique opportunity to address the impact of weight loss intervention on body weight loss, satiety efficiency, eating behavior traits, and psychobehavioral factors in a clinical weight loss population. The present findings are limited to a small sample of individuals who are overweight or obese, which limits the generalization of this study; however, it provides insight into potential targets for weight management.