Insulin levels, hunger, and food intake: an example of feedback loops in body weight regulation

The paper reviews studies considering whether hyperinsulinemia, and its resultant effects on adipose tissue mass, can alter perceived hunger, taste, and food consumption. It also describes work addressing the reciprocal question of whether cues associated with food can affect insulin response. Specifically, four general categories of studies are presented. First, studies considering the causes and physiological consequences of chronic hyperinsulinemia are reviewed. Second, work investigating environmental and cognitive influences on insulin secretion are described. These show that high acute levels of insulin can be produced by simply seeing and thinking about food and that individuals showing this response show a greater tendency toward weight gain in a food-abundant environment. Third, studies are covered in which direct manipulations of insulin level, controlling for blood glucose, are performed. These experiments show that elevations in insulin produce increased hunger, heightened perceived pleasantness of sweet taste, and increased food intake. Finally, a study is described that considers how different insulin levels, produced by the type of food ingested, may affect subsequent food intake. Together, these studies show that "overeating" is caused by a complex feedback system of environmental, behavioral, and biological factors.     

Disorders of Eating in the Elderly

The most common eating disorder in the elderly in both community and hospital settings is food refusal. This may lead to weight loss and malnutrition with all the adverse consequences on independence and function. The management of disorders of eating in the elderly is a diagnostic and therapeutic challenge, requiring the combined skills of the medical and nursing staff. The causes are often multifactorial and require careful and repeated assessment of the patient's social, psychological, and medical history. Approach to treatment involves these factors, as well as ethical and cultural considerations. Eating is the most basic biological drive for survival in nature. In human societies there are additional cultural and social aspects that may override this instinct, as in the case of hunger strikes for political motives. In the elderly, food is one of the major sources of possible pleasure and it is the challenge for health providers to try and give this enjoyment to their patients for as long as possible.     

Salivation discordant with hunger.

In the present study, the authors tested whether an increase in salivation is associated with an increase in subjectively experienced hunger. After conditioning, subjects showed a significant increase in salivation flow. Hunger levels, however, were significantly decreased after conditioning. No correlation was found between salivation flow and hunger levels. It is argued that salivation responses and subjectively experienced hunger are loosely coupled systems. Salivation flow reflects the learning history of a subject which may sometimes be paralleled by a biological state which is called hunger, whereas, at other times, hunger may be absent. The authors conclude that conditioning of preparatory responses such as salivation depends on the probability relationship between exposure to cues (CSs) and food intake (US), as well as the intensity of the US.     

Hunger, eating, and ill health

Humans and other warm-blooded animals living with continuous access to a variety of good-tasting foods tend to eat too much and suffer ill health as a result--a finding that is incompatible with the widely held view that hunger and eating are compensatory processes that function to maintain the body's energy resources at a set point. The authors argue that because of the scarcity and unpredictability of food in nature, humans and other animals have evolved to eat to their physiological limits when food is readily available, so that excess energy can be stored in the body as a buffer against future food shortages. The discrepancy between the environment in which the hunger and eating system evolved and the food-replete environments in which many people now live has led to the current problem of overconsumption existing in many countries. This evolutionary perspective has implications for understanding the etiology of anorexia nervosa.     

Appetitive behavior, compulsivity, and neurochemistry in Prader-Willi syndrome

Advances in genetic research have led to an increased understanding of genotype-phenotype relationships. Excessive eating and weight gain characteristic of Prader-Willi syndrome (PWS) have been the understandable focus of much of the research. The intense preoccupation with food, lack of satiation, and incessant food seeking are among the most striking features of PWS. It has become increasingly clear that the behavioral phenotype of PWS also includes symptoms similar to obsessive compulsive disorder, which in all probability interact with the incessant hunger and lack of satiation to engender the intense preoccupation and food seeking behavior that is characteristic of this disorder. Several lines of evidence suggest that genetic material on chromosome 15 may alter synthesis, release, metabolism, binding, intrinsic activity, or reuptake of specific neurotransmitters, or alter the receptor numbers and/or distribution involved in modulating feeding. Among the likely candidates are GABAnergic, serotonergic, and neuropeptidergic mechanisms. This review summarizes what is known about the appetitive behavior and compulsivity in PWS and discusses the possible mechanisms underlying these behaviors. MRDD Research Reviews 2000;6:125-130.     

Mapping the tip of the tongue--deprivation, sensory sensitisation, and oral haptics

We investigated the impact of food deprivation on oral and manual haptic size perception of food and non-food objects. From relevant theories (need-proportional perception, motivated perception, frustrative nonreward, perceptual defence, and sensory sensitisation) at least four completely different competing predictions can be derived. Testing these predictions, we found across four experiments that participants estimated the length of both non-food and food objects to be larger when hungry than when satiated, which was true only for oral haptic perception, while manual haptic perception was not influenced by hunger state. Subjectively reported hunger correlated positively with estimated object size in oral, but not in manual, haptic perception. The impact of food deprivation on oral perception vanished after oral stimulations even for hungry individuals. These results favour a sensory sensitisation account maintaining that hunger itself does not alter oral perception but the accompanying lack of sensory stimulation of the oral mucosa. Both oral and manual haptic perception tended to underestimate actual object size. Finally, an enhancing effect of domain-target matching was found, ie food objects were perceived larger by oral than by manual haptics, while non-food objects were perceived larger by manual than by oral haptics.     

Compliance with a behavioural weight-loss programme: Target setting and locus of control

The effects on weight loss of two ‘target-setting’ strategies were compared for a sample of obese females following a dietary/behavioural weight-loss programme. Predictions concerning the interaction between target-setting strategy and Locus-of-Control orientation were examined. The option of adopting a ‘variable’ food intake strategy, which allowed compensations or planning variations around an average target, was associated, for externals, with greater weight loss than a ‘consistent’ strategy, in which daily targets for food intake were always the same. Internals did not respond differentially to the two conditions. A measure of verbal intelligence was significantly correlated with control orientation but intelligence was not significantly correlated with weight loss. Some theoretical and clinical implications are discussed.     

生命早期环境不可预测性对过度进食的影响:基于生命史理论

在生命史理论的视角下, 本研究通过两个研究揭示了生命早期环境不可预测性对过度进食的影响及其作用机制。研究1招募处于生命早期阶段的91名初中生(年龄12~14岁), 采用饱食进食(Eating in the absence of hunger, EAH)范式, 结果发现生命早期环境不可预测性能够显著正向预测个体饱食状态下的高热量食物选择(即过度进食); 研究2招募新冠病毒疾病(COVID-19)暴发背景下301名武汉市居民(高死亡威胁组)和179名其他省市居民(控制组) (年龄18~60岁)为被试, 通过问卷法回溯性地测量生命早期环境不可预测性并探究其影响当前过度进食的机制, 结果发现生命早期环境不可预测性通过生命史策略的中介作用间接影响过度进食。同时, 死亡威胁(新冠病毒疫情)扩大了环境不可预测性通过生命史策略间接影响过度进食的效应, 而社会支持则能缓冲这一效应。研究结果为COVID-19背景下和灾后居民的健康进食干预提供了依据。     

Approach bias for food cues in obese individuals

This study aimed to investigate the existence of an approach bias for food cues in obese individuals. A community sample of 56 obese women and 56 normal weight controls completed an approach–avoidance variant of the implicit association task. The obese participants were faster to respond to trials that paired food words with approach words, and trials that paired non-food words with avoid words, than the converse pairings, thus, demonstrating an approach bias for food. This bias was evident for both high caloric and low caloric food words, and was not attributable to a state of deprivation or feelings of hunger. By contrast, the normal weight controls did not show any such bias. The results are consistent with recent neurocognitive perspectives of obesity. At a practical level, approach biases for food may present a potential target for modifying (excessive) food intake.     

Personal Theories of Hunger and Eating1

Recent research on hunger and eating has shown that (a) among individuals with adlibitum access to food, hunger and eating are not regulated by deviations in the body's energy resources from set-points, and (b) it is healthier for people to consume their daily caloric intake as several small snacks than as 3 large meals. People's beliefs about hunger and eating were assessed in 2 questionnaire studies. In Study 1, a large sample of undergraduates was surveyed; in Study 2, dietetics students, nursing students, medical students, dietitians, nurses, and doctors were surveyed. Both studies revealed that people's personal theories of hunger and eating were inconsistent with research findings in ways that could promote overconsumption. These results suggest that educational programs designed to modify the beliefs about hunger and eating of people suffering from problems of overconsumption and of health professionals who treat problems of overconsumption may increase the effectiveness of current treatment regimens.     

Bulimics' responses to food cravings: is binge-eating a product of hunger or emotional state?

This study examined the roles of hunger, food craving and mood in the binge-eating episodes of bulimic patients, and identified the critical factors involved in the processes surrounding binge-eating episodes that follow cravings. This was a prospective study of the binge-eating behaviour of 15 women with bulimia nervosa. The participants used food intake diaries and Craving Records to self-monitor their nutritional behaviour, hunger levels and affective state. Cravings leading to a binge were associated with higher tension, lower mood and lower hunger than those cravings not leading to a binge. Levels of tension and hunger were the critical discriminating variables. The findings of the study support empirical evidence and models of emotional blocking in binge-eating behaviour and challenge the current cognitive starve-binge models of bulimia. The role of food cravings in the emotional blocking model is discussed in terms of a classically conditioned motivational state. Implications for treatment are addressed.     

Trigeminal deafferentation and hunger in the pigeon (Columbia livia).

The location and distribution of the pigeon's trigeminal nerve permit deafferentation of the oral region without affecting motor functions. Although trigeminal deafferentation does not affect drinking, it reduces the efficiency of the consummatory response of eating and disrupts motivational processes underlying hunger and weight regulation. Although the two types of deficit may be experimentally dissociated, trigeminal deafferentation invariably affects both sensorimotor and motivational mechanisms. The deficits in food intake and weight regulation seen after trigeminal deafferentation in the pigeon resemble some components of the "lateral hypothalamic syndrome" in the rat. The results are related to recent studies of the contribution of peripheral and central oropharyngeal factors to the neural control of food intake in both rat and pigeon.     

Hash browns for breakfast,baked potatoes for dinner: Changes in food attitudes as a function of motivation and context

Two studies investigated whether participants' motivational state and the context in which attitude reports are made influence food attitudes. Specifically, these studies examined whether hunger and the time‐typicality of foods (i.e. match or mismatch between the time when a food is typically eaten and the time the attitude is reported) interact to influence reported attitudes. Study 1 suggests that hunger leads to more positive attitudes toward foods that are typically eaten at the time the attitude report is made (e.g. breakfast foods in morning) compared to foods not typically eaten at the time the attitude report is made (e.g. breakfast foods in evening). Study 2 replicates this time‐typical effect of hunger and suggests that time‐typical experience rather than general experience with foods is important for hunger induced attitude change. By demonstrating that food attitudes are influenced by motivational states and the match between when the attitude is reported and when it is typically encountered, the present studies extend previous attitude theory and research that has identified other contextual factors that influence attitude reports. Copyright © 2004 John Wiley & Sons, Ltd.     

The effect of hunger on water intake in rats

Although reciprocal inhibition between eating and drinking has been postulated, the commonly observed reduction of water intake by hungry rats may not be due to any direct inhibitory mechanism. In one experiment rats deprived of food for 24 hr. and then injected with 2 ml. of NaCl drank the same as rats that had received food ad lib. In the second experiment a stomach load of 10 ml. of water 3 hr. before the salt injection was designed to abolish any water deficit that might have occurred during food deprivation had there been inhibition of drinking by hunger. Here again rats deprived of food did not drink less than undeprived animals. In fact the hungry rats drank slightly but significantly more. This phenomenon may be related to the observation confirmed here that during food deprivation rats excrete about twice as much rather dilute urine as during ad lib food intake. This seems to indicate that though in general food deprived rats drink less than normal they actually drink more than they need. Schedule induced polydipsia also occurs during food deprivation and this too makes it unlikely that water-intake is actually inhibited during hunger.     

Attention and disordered eating behavior: II. Disattention to turbulent inner sensations as a risk factor in the development of anorexia nervosa

The Slade model for development of anorexia nervosa proposes that the female may seek success and control in her life by pursuing a thin body through dieting when faced with serious personal problems. Extending upon this model, the present program of research has sought to identify those characteristics of women generally at-risk for anorexia nervosa that would make dieting behavior especially successful, permitting the progression from food restraint into food aversion. The present studies considered whether heightened and stress-related inner stimulation could interfere with the at-risk woman's sensitivity to hunger sensations, thereby decreasing her motivation to eat. A series of analyses conducted within two studies indicated: (1) a relationship between elevated daily stress, concern over being over-whelmed by inner feelings, and a loss of discrimination regarding sources of inner feelings, (2) a tendency to narrow attentional focus when overloaded with excessive internal stimulation, and (3) diminished sensitivity to hunger sensations for women generally at-risk for anorexia nervosa given a narrowed attentional focus.     

Reversal learning as a function of changed reward location or changed drive

In two experiments, rats were trained with food in one location (e.g., black alley) and water in another location (white alley) under hunger or thirst. Subsequently, either the locations of the rewards were reversed, or the drive was changed (from hunger to thirst or thirst to hunger). Reversal of instrumental responses took considerably longer when drive was changed and rewards remained in the same locations than when reward locations were reversed. These results were interpreted as indicating that the animal's internal representations of the rewards received in each location transfer when drive is changed. These internal-reward representations interfere with reversal learning by eliciting the responses which were conditioned to them in Phase 1. Because the values of food and water reverse when drive is changed from hunger to thirst or vice versa, it was suggested that the reward representations surviving the drive shift are cognitive representations of the specific events received (food or water), independent of the value of the rewards under either hunger or thirst.     

Mortality and World Hunger

Why does world hunger hold an inferior place on the contemporary moral agenda? Proposed answer: because it is a political, not a moral problem. It is not a moral problem, because morality needs two conditions fulfilled: that those be in some way close to the agent unto whom that agent is doing something that is to be morally assessed; and that the relevant good or bad states or events can be clearly credited to some particular agent or agents. Neither condition is fulfilled in the case of world hunger. This explains morality's failure to come to grips with it. Yet, while lacking morality's endorsement, the abolition of world hunger may still be a political goal.     

A bioinspired model of short-term satiety of hunger influenced by food properties in virtual creatures

The behavior of the human is continually changed as a consequence of various drives which human is predisposed also of your survival instinct. Among the basic drives of the human, there are the physiological needs and is precisely the hunger that motivates the food intake to get the energy that the body requires via food. The regulation of hunger allows to stop the food intake by means of the homeostatic and hedonic control which are influenced by the food properties. The process that consists of ending the food intake is known as short-term satiety and is important because it limits the amount of food intake; Otherwise, an over-consumed affect the organism functioning negatively. In this paper, we propose a conceptual model for the generation of short-term satiety behaviors based on neuroscientific evidence for virtual creatures. The conceptual model proposed is implemented in a distributed system-a virtual creature endowed with this implementation is placed in a virtual environment to analyze its behavior. The analysis shows how the virtual creature modifies its hunger level (behavior) based on food’s properties. The results show the execution of the process when the creature interacts with the environment.     

A scenario-based dieting self-efficacy scale: the DIET-SE

The article discusses a scenario-based dieting self-efficacy scale, the DIET-SE, developed from dieter's inventory of eating temptations (DIET). The DIET-SE consists of items that describe scenarios of eating temptations for a range of dieting situations, including high-caloric food temptations. Four studies assessed the psychometric properties of the 11-item DIET-SE. Exploratory factor analysis (N = 392) and confirmatory factors analysis (N = 124) revealed three internally consistent and reliable factors representing challenges to adhere to a diet (high-caloric food temptations [HCF], social and internal factors [SIF], negative emotional events [NEE]). Convergent validity is established with other measures of dieting self-efficacy, as well as measures of eating disinhibition, susceptibility to hunger, and weight loss competency. Criterion-related validity is provided through the assessment of goal adherence, and predictive validity is established for dieters' actual food intake (N = 68). The DIET-SE represents a short, reliable, and valid scenario-based measure of dieting self-efficacy.     

Effects of previous delay of reward,generalized effort,and deprivation on impulsiveness

Two experiments investigated the effects of learning and motivational variables upon rats' degree of impulsiveness (choice of a small, immediate reward versus a large, delayed reward). In Experiment 1, food was presented in one of four ways for 24 sessions: fixed-ratio lever pressing requirement, continuous-reinforcement lever-pressing requirement, long intervals between free food presentations, or short intervals between free food presentations. Exposure to the long intervals produced less subsequent impulsiveness in 48 choice trials than did the short intervals, there being no effect of the instrumental requirement. In Experiment 2, there were 48 choice trials in which two hunger levels were combined factorially with two delays of reward for the self-control alternative. Hunger level did not affect implusiveness when there was a short delay, but high hunger increased the impulsiveness when there was a long delay. These results indicate that impulsiveness is affected by prior learning and current motivation. Implications for Baum, Rachlin, and Green's matching formula and for frustration theory are discussed.