Environmental Strategies to Promote Food Intake in Older Adults: A Narrative Review.

Aging is often accompanied by lower intakes of food energy and consequent negative effects on health. To some extent this is due to declines in physiological ability, including the sensory responsiveness to regulate food intake. Fortunately, environmental factors may still influence food intake in older adults. Factors such as social facilitation, modeling, and nutrition knowledge and skills have been shown to stimulate their food intake. While environmental factors such as the eating location, portion size, food presentation, and labeling are known to influence eating behavior, their effectiveness in stimulating food intake in older persons is not well delineated. It is suggested that improving the environmental stimuli that promote food intake is a viable strategy to overcome age-related declines in nutrient intakes. This strategy is so promising that further research is warranted.

Meditation has stronger relationships with mindfulness, kundalini, and mystical experiences than yoga or prayer.

Contemplative practices can have profound effects on mindfulness and on physical and sensory and mystical experiences. Individuals who self-reported meditation, yoga, contemplative prayer, or a combination of practices and their patterns of practice were compared for mindfulness, kundalini effects, and mystical experiences. The results suggest that the amount of practice but not the pattern and social conditions of practice influences mindfulness and possibly mystical experiences. Meditation, yoga, contemplative prayer, or a combination of practices all were found to be associated with enhancements of mindfulness, kundalini effects, and mystical experiences, but meditation had particularly strong associations and may be the basis of the associations of yoga and prayer with these outcomes. The results further suggest that the primary association of contemplative practices is with the real time awareness and appreciation of sensory and perceptual experiences which may be the intermediary between disparate practices and mindfulness, kundalini effects, and mystical experiences.

Overweight and obese humans overeat away from home.

The built environment has been implicated in the development of the epidemic of obesity. We investigated the differences in the meal patterns of normal weight vs. overweight/obese individuals occurring at home vs. other locations. The location of meals and their size in free-living participants were continuously recorded for 7 consecutive days. Study 1: 81 males and 84 females recorded their intake in 7-day diet diaries and wore a belt that contained a GPS Logger to record their location continuously for 7 consecutive days. Study 2: 388 males and 621 females recorded their intake in diet diaries for 7 consecutive days. In both studies, compared to eating at home, overweight/obese participants ate larger meals away from home in both restaurants and other locations than normal weight participants. Overweight/obese individuals appear to be more responsive to environmental cues for eating away from home. This suggests that the influence of the built environment on the intake of overweight/obese individuals may contribute to the obesity epidemic.

Set points, settling points and some alternative models: theoretical options to understand how genes and environments combine to regulate body adiposity.

The close correspondence between energy intake and expenditure over prolonged time periods, coupled with an apparent protection of the level of body adiposity in the face of perturbations of energy balance, has led to the idea that body fatness is regulated via mechanisms that control intake and energy expenditure. Two models have dominated the discussion of how this regulation might take place. The set point model is rooted in physiology, genetics and molecular biology, and suggests that there is an active feedback mechanism linking adipose tissue (stored energy) to intake and expenditure via a set point, presumably encoded in the brain. This model is consistent with many of the biological aspects of energy balance, but struggles to explain the many significant environmental and social influences on obesity, food intake and physical activity. More importantly, the set point model does not effectively explain the 'obesity epidemic'--the large increase in body weight and adiposity of a large proportion of individuals in many countries since the 1980s. An alternative model, called the settling point model, is based on the idea that there is passive feedback between the size of the body stores and aspects of expenditure. This model accommodates many of the social and environmental characteristics of energy balance, but struggles to explain some of the biological and genetic aspects. The shortcomings of these two models reflect their failure to address the gene-by-environment interactions that dominate the regulation of body weight. We discuss two additional models--the general intake model and the dual intervention point model--that address this issue and might offer better ways to understand how body fatness is controlled.

The control of food intake of free-living humans: putting the pieces back together.

The control of food intake has been studied using reductionism; by separately investigating environmental, physiological, and genetic variables. The general model of intake regulation attempts to reassemble the pieces into an organized whole. It postulates that intake is influenced by sets of both physiological factors which have negative feedback loops to intake and environmental factors which do not. Data and behavioral genetic analysis on a number of environmental, psychological, dietary, and social variables demonstrate that they have large impacts on the intake of free-living humans in their everyday environments and their magnitude and impact on intake are influenced by heredity. Recent evidence of built environment influences on activity and intake further indicate the profound influence of environmental circumstances on both intake and expenditure. A computer simulation of the general model of intake regulation demonstrates that the model predicts different maintained levels of intake and body weight depending upon the external environment and that change in the environment can produce new sustained levels. It is suggested that eating is influenced by a myriad of physiological and non-physiological factors and that total intake results from the integral of their influences. It is concluded that recombining the components broken down in the reductionistic process results in a functional whole that can well describe human behavior in natural environments. The paper represents an invited review by a symposium, award winner or keynote speaker at the Society for the Study of Ingestive Behavior [SSIB] Annual Meeting in Portland, July 2009.

When, how much and what foods are eaten are related to total daily food intake.

Intake in the morning is associated with a reduction in the total intake for the day, while intake at night is associated with greater overall daily intake. These associations are macronutrient specific, with morning carbohydrate intake associated with reduced daily carbohydrate intake, morning fat intake associated with reduced daily fat intake and morning protein intake associated with reduced daily protein intake. Since different types of foods contain differing proportions of macronutrients, the present study investigated the associations of different types of foods ingested at various times of day with total daily and macronutrient intakes. The intakes of 388 male and 621 female free-living individuals reported in 7 d diet diaries were reanalysed. The intakes of twenty-four different types of foods and seven different drinks occurring during the morning (04.00-10.29 hours), afternoon (10.30-16.59 hours) and evening (17.00-02.00 hours) were identified and related to overall daily intakes. Dairy foods, ice cream, beef, other meats, potatoes, pastry, nuts, chips and snacks, condiments, alcohol and soda were significantly associated with higher total intake over the day, while fruit, soup, breakfast cereal, pasta, pizza, water, coffee/tea and diet soda were either not associated or were associated with lower overall intake. Dietary energy density appeared to mediate the associations between particular foods and beverages and overall energy intake. This suggests that eating low-density foods in the morning and avoiding high-density foods at night might aid in reducing overall intake and may be useful in dietary interventions for overweight and obesity.

A small-changes approach reduces energy intake in free-living humans.

OBJECTIVE: America On the Move (AOM) is a national weight gain prevention initiative that promotes small lifestyle changes by increasing walking by 2000 steps/day and reducing energy intake by about 100 kcal/day. The study's intent was to determine the impact of these small changes recommendations on steps/day and energy intake. METHODS: In this cross-sectional study, food and fluid intake and physical activity in 116 healthy overweight adults (BMI: 25-36 kg/m(2); age: 18-60y) was compared between a non-intervention and an intervention week using diet diaries and pedometers. The major outcomes were steps/day, daily caloric intake, macronutrient intake and meal size. Within subject ANOVAs were conducted to compare results between intervention and non-intervention weeks. RESULTS: Total energy intake was lower during intervention week than non-intervention week (P < .01), including macronutrient contents (all P's < .01), meal size (P < .01), consumption of sugar (P < .01), sugared sodas (P < .01) and sodium (P < .01). Steps/day were higher during intervention week than non-intervention week (P < .01). CONCLUSIONS: The results support previous research showing that the message to increase steps/day results in an increase in physical activity. The results demonstrate for the first time that the message to reduce intake by 100 kcal/day does actually result in a lower intake in the short term. People seem to be able to make positive changes in diet and physical activity in response to these messages. If these small changes can be sustained, this approach could be effective in preventing further weight gain in the population.

Smoking status relationships with the food and fluid intakes of free-living humans.

OBJECTIVE: The relation of cigarette smoking to food and fluid intakes was studied. METHODS: Ninety-nine smoking and 551 non-smoking free-living adult humans provided a detailed record of their eating and drinking in 7-d diaries. RESULTS: Cigarette smoking was associated with significant changes in overall intakes and meal pattern. Smokers had higher intakes of fluids in the form of drinks due to higher levels of alcohol and coffee/tea consumption. Smokers were less hungry but more responsive to social facilitation and time of day. There were also substantial gender differences in smoking relations to intake, with male smokers tending to have higher overall and meal intakes particularly of fats than non-smokers, whereas female smokers tended to have lower overall intakes, fewer meals, and lower amounts of carbohydrates than non-smokers. Male smokers tended to be less responsive to their before-meal stomach content, their level of hunger, and the palatability of the meal than non-smokers, whereas females tend to be more responsive to all of these influences on meal size. CONCLUSION: These results suggest that smoking has very few direct simple effects on intake but rather influences intake indirectly through its covariation with alcohol and caffeine intakes and with dietary restraint and that smoking has different, sometimes opposite, influences in males and females.

The time of day and the proportions of macronutrients eaten are related to total daily food intake.

Intake in the morning is particularly satiating and associated with lower total amounts ingested for the day while intake at night is associated with greater overall daily intake. But, the influence of carbohydrates, fats or proteins ingested at various times of the day is unknown. The intakes of 375 male and 492 female free-living individuals that were acquired with 7 d diet-diary reports were reanalysed. The intakes of carbohydrates, fats and proteins, and the density of intake occurring during three 6 h periods (06.00 to 11.59 hours (morning), 12.00 to 17.59 hours (afternoon) and 18.00 to 23.59 hours (evening)) were identified and related to overall daily and meal intakes. Energy density of intake during all periods was found to be positively related to overall intake. When the proportion of daily carbohydrate ingested in the morning was high, less total food energy and carbohydrate were ingested over the entire day. When the proportion of daily fat ingested in the morning was high, less total food energy and carbohydrate and fat were ingested over the entire day. When the proportion of daily protein ingested in the morning was high, less protein was ingested over the entire day. Conversely, when intake was relatively high in the evening of either total food energy, carbohydrate or fat, then overall daily energy intakes tended to be higher. The results suggest that the morning intake association with reduced total intake is macronutrient specific, with morning carbohydrate, fat and protein intake associated with reduced daily carbohydrate, fat and protein intake, respectively.

Influence of physiological and subjective arousal on food intake in humans.

OBJECTIVES: This study explored the influence of physiologic and subjective arousal on ambient factors of the food environment, such as the eating location, the presence of other people, sound, and time of day and on food intake. It was hypothesized that the influence of environmental stimuli on food intake would be mediated by arousal. METHODS: College students were asked to wear heart rate monitors and to record their food intake in a 7-d diet diary. Subjective arousal (elation and excitement) and aspects of the eating environment were recorded for each meal occasion. RESULTS: Results showed that subjective arousal seems to be related to food intake (P < 0.01) and appears to be affected by environmental stimuli such as the eating location (P < 0.01) and the number of people present (P < 0.01), but only small effects of some environmental stimuli on heart rate were found with higher average heart rates in restaurants (P < 0.05). No effects of heart rate on food intake were detected. Regression analyses failed to show arousal as a significant mediator between environmental stimuli and food intake. CONCLUSION: It can be concluded that, for normal individuals in their everyday environment, ambient influences on food intake are not mediated by changes in arousal. However, the environment and the emotional state of the individual appear to play a role in the individual's eating behavior.

Listening to music while eating is related to increases in people's food intake and meal duration.

The relationship of listening to music while eating with food consumption in the natural environment was assessed in 78 college students. They recorded their food intake along with environmental factors such as meal duration, music, including speed and volume, location, number of people present and the time of day in a detailed diet diary for 7 consecutive days. The data show that the presence of music is associated with higher food intake. Within subject comparisons revealed higher food and fluid intake and longer meal duration while listening to music but no significant differences in music speed or volume. The likelihood of listening to music appeared to be associated with the environmental variables of the number of people present and the time of day. The presence of music appears to be one of a set of environmental factors that influences food and fluid intake in the natural world.

Varying levels of food energy self-reporting are associated with between-group, but not within-subject, differences in food intake.

Energy intakes reported in diet diaries are frequently significantly below the energy requirements for a weight-stable individual. To investigate the impact of low energy reporting on between-group comparisons and within-subject analyses of eating behavior, we examined the baseline 7-d food-intake diaries submitted by 365 male and 564 female free-living normal adult humans. Participants were separated into 5 different groups, based upon their levels of energy reporting relative to their predicted basal metabolic rate: EI:BMR(est) = 0-0.99, 1.0-1.199, 1.2-1.399, 1.3-1.599, and > or =1.6. Between-group analysis revealed significant inverse relations among reporting level and body weight, BMI, cognitive restraint, positive relations with intake, meal size, and meal frequency. On the other hand, within-subject analyses suggested that, regardless of the level of energy reporting, equivalent relations are found among the amounts eaten in meals and the presence of other people, palatability, hunger, satiety, dietary energy density, contents of the stomach, time since the last meal, and time of day and correlations between daily intake and intake on subsequent days. The results suggest that comparing the intakes reported in diet diaries by different groups may be confounded by group differences in reporting levels. In contrast, the results clearly support the conclusion that diet diary data are suitable for assessing the relations between variables assessed within subjects irrespective of the level of reporting of energy intake.

Macronutrient and dietary energy density influences on the intake of free-living humans.

The influence of the composition of foods, their macronutrient contents and the dietary energy densities on intake, were investigated by analyzing 7-day diet diary reports from 669 free-living normal adult humans who adequately reported intake. The analyses revealed subtle but small macronutrient specific relationships with intake. Dietary energy density, however, was found to have large reliable short-term relationships with intake. The results support the hypothesis that short-term intake is controlled on the basis of the volume of nutrients in the stomach at the end of the meal and not upon their food energy or macronutrient contents.

Heredity influences the dietary energy density of free-living humans.

Dietary energy density has been shown to have large effects on short-term food intake. Little is known, however, about its origins. We investigated the influence of heredity, shared (familial) environment, and individual environment on dietary energy density and its relationship to food intake with 110 identical and 102 fraternal same-sex and 53 fraternal mixed gender adult twin pairs who were paid to maintain 7-day food intake diaries. From the diary reports, the total and meal intakes of food energy, the amounts of the macronutrients ingested, and dietary energy density were estimated. Linear structural modeling was applied to investigate the nature and degree of genetic and environmental influences. The analysis revealed significant genetic and individual environmental, but not shared (familial) environmental, influences on the dietary densities of the reported diets. But, there was no genetic or familial influences on the responsiveness of the individual to dietary density. Dietary energy density appears to be another component in a package of genetically determined physiological, sociocultural, and psychological processes that influence the regulation of energy balance.

Stomach filling may mediate the influence of dietary energy density on the food intake of free-living humans.

The energy density of the diet has been demonstrated to be a significant influence on the daily intakes of humans which has led to the hypothesis that intake control is based upon the weight and volume of food and not its energy content. The study explored the roles of the components used in the calculation of energy density and stomach filling in dietary energy density effects upon intake. Dietary energy density relationships with intake and body size were studied in 264 male and 406 female free-living adult humans who provided a detailed record of their eating and drinking in 7-day diaries. High energy density was associated with larger amounts of food energy and larger amounts of solids, but lower total weight of meals, daily intakes, and weekly intakes. The lower total weight occurred due to lower fluid intake in drinks. Multiple regression analysis revealed that overall dietary energy density was more important than the energy density of particular nutrients. Intake of fluids in drinks did not contribute to the relationship of dietary energy density with intake. The estimated weight of the contents of the stomach following the meals was relatively constant regardless of the energy density of the meals, daily, or weekly intakes. Energy density was not significantly related with body size, height, weight, or BMI. The findings support the notion that short-term intake is controlled on the basis of its weight and volume as opposed to its food energy content.

Influence of heredity on dietary restraint, disinhibition, and perceived hunger in humans.

OBJECTIVE: Dietary restraint, disinhibition, and perceived hunger have been shown to affect food intake and body weight and are thought to be risk factors for eating disorders, but little is known about their origins. We investigated the influence of heredity, shared (familial) environment, and individual environment on dietary restraint disinhibition, perceived hunger and their relation to body size and food intake. METHODS: Scores on the Three Factor Eating Questionnaire and the Restraint Scale in addition to height, weight, body mass index, and 7-d diary reported nutrient intakes were obtained from 39 identical, 60 fraternal same-sex, and 50 fraternal opposite-sex adult twin pairs who were living independently. Linear structural modeling was applied to investigate the nature and degree of genetic and environmental influences. RESULTS: Analysis showed significant genetic and individual environmental, but not shared (familial) environmental, influences on cognitive restraint, perceived hunger, and Restraint Scale scores, with genes accounting for 44%, 24%, and 58% of the variance, respectively. In contrast, disinhibition was found to be significantly influenced by the shared (familial) environment, accounting for 40% of the variance. Further analysis showed that cognitive restraint and perceived hunger heritabilities could not be accounted for by significant heritabilities of body weight, height, or body mass index. In contrast, the heritability of Restraint Scale scores was found to be related to body size. Cognitive restraint was negatively correlated with nutrient intake, and differences in cognitive restraint were found to be related to differences in the body sizes of identical twin pairs. CONCLUSIONS: Dietary restraint appears to be another component in a package of genetically determined physiologic, sociocultural, and psychological processes that regulate energy balance, whereas dietary disinhibition may be the intermediary between upbringing and the development of overweight and/or eating disorders.

Genes, the environment and the control of food intake.

Genes are known to have independent influences on the height and weight of individuals, their overall levels of nutrient intakes and their meal sizes and frequencies. Recent evidence suggests that genes exert multiple and subtle influences on the controls of food intake. There are significant genetic influences on the level and responsiveness of the individual to physiological factors, such as the preprandial stomach contents of nutrients and subjective hunger, and also to environmental and psychological factors such as social facilitation of eating, diurnal rhythms of intake, palatability, cognitive restraint and dietary density. The general model of intake regulation provides an integrated and comprehensive account of how these physiological and environmental factors might fit together to produce the control of intake and body weight.

When identical twins differ: an analysis of intrapair differences in the spontaneous eating behavior and attitudes of free-living monozygotic twins.

Heredity has been shown to have major influences on the body size and ingestive behaviors of humans. However, environment is also important as evidenced by the fact that even identical twins can differ in body size and nutrient intake. To investigate the relative influence of heredity and environment, differences between the body size and food intake of 110 identical adult twin pairs who were living independently were studied with a 7-day diet diary technique. Differences within twin pairs (intrapair differences) in diet density were related to differences in daily intakes, but not with body size differences. On the other hand, cognitive restraint and disinhibition were related to intrapair differences in body size, but not intake. The fact that there are important environmental and psychological factors that influence intake and body size, even in individuals who have identical genotypes, supports the recently proposed general model of intake regulation [de Castro JM, Plunkett S. A general model of intake regulation. Neurosci. Biobehav. Rev. 26 (5) (2002) 581-595].

Effect of ambience on food intake and food choice.

Eating takes place in a context of environmental stimuli known as ambience. Various external factors such as social and physical surroundings, including the presence of other people and sound, temperature, smell, color, time, and distraction affect food intake and food choice. Food variables such as the temperature, smell, and color of the food also influence food intake and choice differently. However, the influence of ambience on nutritional health is not fully understood. This review summarizes the research on ambient influences on food intake and food choice. The literature suggests that there are major influences of ambience on eating behavior and that the magnitude of the effect of ambience may be underestimated. Changes in intake can be detected with different levels of the number of people present, food accessibility, eating locations, food color, ambient temperatures and lighting, and temperature of foods, smell of food, time of consumption, and ambient sounds. It is suggested that the manipulation of these ambient factors as a whole or individually may be used therapeutically to alter food intake and that more attention needs to be paid to ambience in nutrition-related research.