Eating behaviour, food preferences and dietary intake in relation to obesity and body-weight status

Effects of low-carbohydrate diets versus low-fat diets on metabolic risk factors in overweight and obese adults: A meta-analysis of randomized controlled trials

Background and aims

Low-carbohydrate diets (LCD) and low-fat diets (LFD) have shown beneficial effects on the management of obesity. Epidemiological studies were conducted to compare the effects of the two diets. However, the results were not always consistent. This study aimed to conduct a meta-analysis to compare the long-term effects of LCD and LFD on metabolic risk factors and weight loss in overweight and obese adults.

Methods

We performed a systematic literature search up to 30 March, 2022 in PubMed, EMBASE, and Cochrane Library. The meta-analysis compared the effects of LCD (carbohydrate intake ≤ 40%) with LFD (fat intake < 30%) on metabolic risk factors and weight loss for ≥6 months. Subgroup analyses were performed based on participant characteristics, dietary energy intake, and the proportions of carbohydrates.

Results

33 studies involving a total of 3,939 participants were included. Compared with participants on LFD, participants on LCD had a greater reduction in triglycerides (–0.14 mmol/L; 95% CI, –0.18 to –0.10 mmol/L), diastolic blood pressure (–0.87 mmHg; 95% CI, –1.41 to –0.32 mmHg), weight loss (–1.33 kg; 95% CI, –1.79 to –0.87 kg), and a greater increase in high-density lipoprotein cholesterol (0.07 mmol/L; 95% CI, 0.06 to 0.09 mmol/L) in 6–23 months. However, the decrease of total cholesterol (0.14 mmol/L; 95% CI, 0.07 to 0.20 mmol/L) and low-density lipoprotein cholesterol (0.10 mmol/L; 95% CI, 0.06 to 0.14 mmol/L) was more conducive to LFD in 6–23 months. There was no difference in benefits between the two diets after 24 months. Subgroup analyses showed no significant difference in the reduction of total cholesterol, low-density lipoprotein cholesterol, and blood pressure between the two diets in participants with diabetes, hypertension, or hyperlipidemia.

Conclusion

The results suggest that LCD and LFD may have specific effects on metabolic risk factors and weight loss in overweight and obese adults over 6 months. At 24 months, the effects on weight loss and improvement of metabolic risk factors were at least the same. These indicated that we might choose different diets to manage the overweight and obese subjects. However, the long-term clinical efficacy and effects of various sources of carbohydrates or fat in the two diets need to be studied in the future.

Do Mindfulness Interventions Improve Obesity Rates in Children and Adolescents: A Review of the Evidence

Mindfulness interventions have shown promise in improving self-regulation, depression, anxiety, and stress levels across all ages. Obesity rates in children are rising worldwide. It has been postulated that through improvements in self-regulation with mindfulness interventions, obesity rates can be improved in children and adolescents. In this review, we attempt to explain how mindfulness interventions may impact obesity rates and obesity-related complications and give the current state of evidence for the following mindfulness interventions: Mindful Eating, Mindfulness-Based Stress Reduction, Yoga, Spirituality, and Dialectical Behavior Therapy.

Impact of childhood experience and adult well-being on eating preferences and behaviours

OBJECTIVES

To examine the relative contribution of childhood experience, measured by childhood violence and childhood happiness, and adult well-being on adult eating preferences and behaviours, independent of proximal factors such as current deprivation.

DESIGN

A cross-sectional, stratified, randomised sample survey using retrospective measures of childhood violence and happiness and self-reported measures of current well-being.

SETTING

The North West Region of England between September 2012 and March 2013.

PARTICIPANTS

Individuals aged 18-95-year-olds from randomly selected households (participation was successful for 90% of eligible households and 78% of the total visited addresses; n=11,243).

OUTCOMES

Dichotomised measures for preference of healthy foods or 'feel good' foods and low or high daily fruit and vegetable consumption.

RESULTS

After correcting for demographics, combined categories for childhood experience and dichotomised measures of adult well-being were found to be significantly related to adult food preferences and eating behaviours. Participants with unhappy and violent childhoods compared to those with happy and non-violent childhoods had adjusted ORs (95% CI, significance) of 2.67 (2.15 to 3.06, p<0.001) of having low daily fruit and vegetable intake (two or less portions) and 1.53 (1.29 to 1.81, p<0.001) of choosing 'feel good' foods over foods which were good for their long term health.

CONCLUSIONS

Daily intake of fruit and vegetables, linked to non-communicable diseases, and preference for 'feel good' foods, linked to obesity, are affected by childhood experience and adult well-being independent of demographic factors. Preventative interventions which support parent-child relationships and improve childhood experience are likely to reduce the development of poor dietary and other health-risk behaviours.

Allopregnanolone preferentially induces energy-rich food intake in male Wistar rats

Obesity is an increasing problem and identification of the driving forces for overeating of energy‐rich food is important. Previous studies show that the stress and sex steroid allopregnanolone has a hyperphagic effect on both bland food and palatable food. If allopregnanolone induces a preference for more palatable or for more energy‐rich food is not known. The aim of this study was to elucidate the influence of allopregnanolone on food preference. Male Wistar rats were subjected to two different food preference tests: a choice between standard chow and cookies (which have a higher energy content and also are more palatable than chow), and a choice between a low caloric sucrose solution and standard chow (which has a higher energy content and is less palatable than sucrose). Food intake was measured for 1 h after acute subcutaneous injections of allopregnanolone. In the choice between cookies and chow allopregnanolone significantly increased only the intake of cookies. When the standard chow was the item present with the highest caloric load, the chow intake was increased and allopregnanolone had no effect on intake of the 10% sucrose solution. The increased energy intakes induced by the high allopregnanolone dose compared to vehicle were very similar in the two tests, 120% increase for cookies and 150% increase for chow. It appears that in allopregnanolone‐induced hyperphagia, rats choose the food with the highest energy content regardless of its palatability.

We show that allopregnanolone increased the consumption of the more calorie dense food offered in different food preference situations, while palatability was of secondary importance. Thus, it seems as allopregnanolone treatment could favor ingestion of a more energy‐rich diet.

The effect of exercise on carbohydrate preference in female rats

Exercise has a myriad of health benefits, including positive effects against heart disease, diabetes, and dementia. Cognitive performance improves following chronic exercise, both in animal models and humans. Studies have examined the effect of exercise on feeding, demonstrating a preference towards increased food consumption. Further, sex differences exist such that females tend to prefer carbohydrates over other macronutrients following exercise. However, no clear effect of exercise on macronutrient or carbohydrate selection has been described in animal or human studies. This research project sought to determine the effect of voluntary exercise on carbohydrate selection in female rats. Preference for a complex (starch) versus a simple (dextrose) carbohydrate was assessed using a discriminative preference to context paradigm in non-exercising and voluntarily exercising female rats. In addition, fasting blood glucose and performance in the Morris water task was examined in order to verify the effects of exercise on performance in this task. Female rats given access to running wheels preferred a context previously associated with starch, whereas females with no running wheel access preferred a context previously associated with dextrose. No changes in blood glucose were observed. However, cognitive differences in the Morris water task were observed such that voluntary exercise allowed rats to find a new location of a hidden platform following 4 days of training to an old platform location. These results suggest that voluntary exercise may decrease preservative behaviors in a spatial navigation task through the facilitation of plasticity mechanisms. This study is the first of its kind to demonstrate the influence of exercise on taste preference for complex and simple carbohydrates with this context conditioning paradigm.

A reciprocal interaction between food-motivated behavior and diet-induced obesity

OBJECTIVES

One of the main causes of obesity is overconsumption of diets high in fat and sugar. We studied the metabolic changes and food-motivated behavior when rats were subjected to a choice diet with chow, lard and a 30% sucrose solution (high fat high sugar (HFHS)-choice diet). Because rats showed considerable variations in the feeding response to HFHS-choice diet and in food-motivated behavior, we investigated whether the motivation to obtain a sucrose reward correlated with the development of obesity when rats were subsequently subjected to HFHS-choice diet.

METHOD

We first studied feeding, locomotor activity and body temperature, fat weights and hormonal concentrations when male Wistar rats were subjected to HFHS-choice diet for 1 week. Second, we studied sucrose-motivated behavior, using a progressive ratio (PR) schedule of reinforcement in rats that were subjected to the HFHS-choice diet for at least 2 weeks, compared to control rats on a chow diet. Third, we measured motivation for sucrose under a PR schedule of reinforcement in rats that were subsequently subjected to HFHS-choice diet or a chow diet for 4 weeks. Fat weights were measured and correlated with the motivation to obtain sucrose pellets.

RESULTS

One week on the HFHS-choice diet increased plasma concentrations of glucose and leptin, increased fat stores, but did not alter body temperature or locomotor activity. Moreover, consuming the HFHS-choice diet for several weeks increased the motivation to work for sucrose pellets. Furthermore, the motivation to obtain sucrose pellets correlated positively with abdominal fat stores in rats subsequently subjected to the HFHS-choice diet, whereas this correlation was not found in rats fed on a chow diet.

CONCLUSION

Our data suggest that the motivation to respond for palatable food correlates with obesity due to an obesogenic environment. Conversely, the HFHS-choice diet, which results in obesity, also increased the motivation to work for sucrose. Thus, being motivated to work for sucrose results in obesity, which, in turn, increases food-motivated behavior, resulting in a vicious circle of food motivation and obesity.

Eating behaviors and indexes of body composition in men and women from the Québec family study

OBJECTIVE

To put into relationship the dietary and anthropometric profile of men and women with their eating behaviors (cognitive dietary restraint, disinhibition, and susceptibility to hunger) and to assess whether gender and obesity status influence these associations.

RESEARCH METHODS AND PROCEDURES

Anthropometric measurements (including visceral adipose tissue accumulation), dietary profile (3-day food record), and eating behaviors (Three-Factor Eating Questionnaire) were determined in a sample of 244 men and 352 women.

RESULTS

Women had significantly higher cognitive dietary restraint and disinhibition scores than men (p < 0.0001). In both genders, scores for disinhibition and susceptibility to hunger, but not for cognitive dietary restraint, were higher in obese subjects than in overweight and nonobese subjects (p < 0.05). Positive correlations were observed between rigid restraint and most of the anthropometric variables studied (0.12 <or= r <or= 0.16). Moreover, in women, flexible restraint was negatively associated with body fat and waist circumference (r = -0.11). Cognitive dietary restraint and rigid restraint were positively related to BMI among nonobese women (0.19 <or= r <or= 0.20), whereas in obese men, cognitive dietary restraint and flexible restraint tended to be negatively correlated with BMI (-0.20 <or= r <or= -0.22; p = 0.10).

DISCUSSION

Gender could mediate associations observed between eating behaviors and anthropometric profile. It was also found that disinhibition and susceptibility to hunger are positively associated with the level of obesity. On the other hand, cognitive dietary restraint is not consistently related to body weight and adiposity, whereas rigid and flexible restraint are oppositely associated to obesity status, which suggests that it is important to differentiate the subscales of cognitive dietary restraint. Finally, counseling aimed at coping with disinhibition and susceptibility to hunger could be of benefit for the long-term treatment of obesity.

Human eating behaviour in an evolutionary ecological context

Present-day human eating behaviour in industrialised society is characterised by the consumption of high-energy-density diets and often unstructured feeding patterns, largely uncoupled from seasonal cycles of food availability. Broadly similar patterns of feeding are found among advantaged groups in economically-emerging and developing nations. Such patterns of feeding are consistent with the evolutionary ecological understanding of feeding behaviour of hominids ancestral to humans, in that human feeding adaptations are likely to have arisen in the context of resource seasonality in which diet choice for energy-dense and palatable foods would have been selected by way of foraging strategies for the maximisation of energy intake. One hallmark trait of human feeding behaviour, complex control of food availability, emerged with Homo erectus (1.9 x 10(6)-200000 years ago), who carried out this process by either increased meat eating or by cooking, or both. Another key trait of human eating behaviour is the symbolic use of food, which emerged with modern Homo sapiens (100000 years ago to the present) between 25000 and 12000 years ago. From this and subsequent social and economic transformations, including the origins of agriculture, humans have come to use food in increasingly elaborate symbolic ways, such that human eating has become increasingly structured socially and culturally in many different ways.

Taste, food intake and obesity

Research in human eating behaviour prior to 1990 has shown that taste impacts the palatability and selection of food for intake; sensory-specific satiety; satiation; and thermic effect of food. Research in the last decade has added information to these areas; expanded the field to comparisons of the impact of 'wanting' vs. 'liking' food on intake, and provided insight into the relationship of food intake and brain functioning through new imaging techniques. This article will review literature from the last decade on research in the area of taste and its impact on food intake. Emphasis will be placed on differences seen between lean and obese humans and how these may contribute to the development of human obesity. Suggestions for future research directions will also be discussed.

Failure of preoperative resting energy expenditure in predicting weight loss after gastroplasty

OBJECTIVE

To evaluate the predictive efficacy of preoperative resting energy expenditure (REE) on weight loss after vertical banded gastroplasty (VBG). When subjected to a gastric restriction procedure of similar extent, the patients with higher energy expenditure should experience a greater negative energy balance than those with lower-energy expenditure, and thus, lose more weight, thereby making REE a reliable predictor of weight loss after VBG.

RESEARCH METHODS AND PROCEDURES

This was a prospective investigation after VBG, taking into account the relationship between preoperative REE values and the results at 1-year follow-up in terms of weight loss and success of the procedure. The correlations were evaluated by multiple and logistic regression analysis.

RESULTS

The weight loss and the outcome at 1 year after VBG seemed to be completely independent of preoperative energy expenditure.

DISCUSSION

These findings suggest that, despite gastric restriction, patients may voluntarily adjust their energy intake, and that the weight outcome after VBG is influenced more by behavioral and cognitive variables than by biological or surgical factors.

Sociodemographic and psychological predictors of changes in dietary fat consumption in adults with high blood cholesterol following counseling in primary care

The associations between sociodemographic variables, psychological factors, and changes in dietary fat consumption over 4 months were assessed in a randomized controlled trial of behavioral counseling versus standard advice. Patients were 141 men and 150 women, with an average age of 52.1 years and total cholesterol level of 7.27 mmol/l (278 mg/dl). Smokers, younger patients, and those with greater body mass index had higher fat intake at baseline. Behavioral counseling led to greater reductions in fat intake than did standard advice. Self-efficacy and ratings of benefits of low-fat diets were related to fat consumption at baseline, and changes in these measures were correlated with changes in fat intake. Family support, baseline anticipated regret, and (for the behavioral counseling group only) baseline behavioral intentions predicted reductions in fat intake. The results indicated that psychosocial variables associated cross-sectionally with fat consumption do not necessarily predict change and that factors involved in the process of change and the prediction of change need to be differentiated.

Macronutrient diet selection in thirteen mouse strains

The strain distribution for macronutrient diet selection was described in 13 mouse strains (AKR/J, NZB/B1NJ, C57BL/6J, C57BL/6ByJ, DBA/2J, SPRET/Ei, CD-1, SJL/J, SWR/J, 129/J, BALB/cByJ, CAST/Ei, and A/J) with the use of a self-selection protocol in which separate carbohydrate, fat, and protein diets were simultaneously available for 26-30 days. Relative to carbohydrate, nine strains consumed significantly more calories from the fat diet; two strains consumed more calories from carbohydrate than from fat (BALB/cByJ, CAST/Ei). Diet selection by SWR/J mice was variable over time, resulting in a lack of preference. One strain (A/J) failed to adapt to the diet paradigm due to inadequate protein intake. Comparisons of proportional fat intake across strains revealed that fat selection/consumption ranged from 26 to 83% of total energy. AKR/J, NZB/B1NJ, and C67BL/6J mice self-selected the highest proportion of dietary fat, whereas the CAST/Ei and BALB/cByJ strains chose the lowest. Finally, epididymal fat depot weight was correlated with fat consumption. There were significant positive correlations in AKR/J and C57BL/6J mice, which are highly sensitive to dietary obesity. However, absolute fat intake was inversely correlated with epididymal fat in two of the lean strains: SWR/J and CAST/Ei. We hypothesize that the SWR/J and CAST/Ei strains are highly sensitive to a negative feedback signal generated by increasing body fat, but the AKR/J and C67BL/6J mice are not. The variation in dietary fat selection across inbred strains provides a tool for dissecting the complex genetics of this trait.

Knowledge of calories and its effect on eating behavior in overweight, normal weight, and underweight individuals

BACKGROUND

To assess changes in the eating behavior of overweight, normal weight, and underweight individuals in response to knowledge about the caloric content of their food.

METHODS

Anonymous self-report questionnaires were completed by 1041 staff members attending the Innsbruck University Hospital cafeteria shortly after it started to display the caloric content of all meals. The questions covered the subjects' weight history, body image, eating behavior, and response to knowledge of caloric content.

RESULTS

Among the respondents, 141 were classified as overweight, 728 as normal weight, and 118 as underweight. Overweight individuals reported a significantly more frequent change in eating behavior in response to the information, and were also significantly more distressed about weight and eating and dissatisfied with their bodies and their weight than normal and underweight individuals.

CONCLUSIONS

Overweight individuals were more likely to report that they had modified their eating in response to information about calories. Whether this reflects an actual change in eating behavior, or merely a wish to give socially desirable responses, remains uncertain.

Divergence in proportional fat intake in AKR/J and SWR/J mice endures across diet paradigms

These experiments were designed to test the hypothesis that the contrasting patterns of macronutrient selection described previously in AKR/J (fat preference) and SWR/J (carbohydrate preference) mice are not dependent on a single diet paradigm. The effect of mouse strain on proportional fat intake was tested in naive mice by presenting two-choice diets possessing a variety of physical, sensory, and nutritive properties. In three separate experiments, AKR/J mice preferentially selected and consumed a higher proportion of energy from the high-fat diet than SWR/J mice. Specifically, this phenotypic difference was observed with 1) fat-protein vs. carbohydrate-protein diets, independent of fat type (vegetable shortening or lard), 2) isocaloric, high- vs. low-fat liquid diet preparations, and 3) high- vs. low-fat powdered-granular diets. These results confirm our previous observation of a higher proportional fat intake by AKR/J compared with SWR/J mice using the three-choice macronutrient selection diet and show that this strain difference generalizes across several diet paradigms. This strain difference is due largely to the robust and reliable fat preference of the AKR/J mice. In contrast, macronutrient preference in SWR/J mice varied across paradigms, suggesting a differential response by this strain to some orosensory or postingestive factor(s).

Sensory and hedonic judgments of common foods by lean consumers and consumers with obesity

OBJECTIVE

To establish differences between lean subjects and subjects with obesity in subjective reports of predominant taste and texture attributes of common foods, and the relationships of these qualities and foods with overall liking.

RESEARCH METHODS AND PROCEDURES

Twenty lean (body mass index: 20 to 25 kg/m2) nondieting healthy adults and 23 (body mass index: > or = 30 kg/m2) nondieting healthy adults with obesity assigned ratings for pleasantness and predominant sensory attributes to 50 common foods in 14 food groups using a questionnaire. They completed the Dutch Eating Behavior Questionnaire. Body composition was assessed by bioelectrical impedance.

RESULTS

There were no significant group differences between pleasantness scores overall; however, lean subjects assigned higher scores to fruits and vegetables, to foods self-classified as sweet and as salty/savory, and to foods grouped in the highest and lowest quintiles of percentage food energy from fat. There were no group differences in free-choice texture descriptors applied to foods, but correspondence analysis revealed that subjects with obesity associated coarse, slippery, tough, and fatty textures with "dislike extremely," whereas lean subjects associated grainy, moist, doughy, and fibrous texture with "like extremely." Analyses reduced texture terms to 39 key descriptors for use in subsequent work. Groups did not significantly differ in reported external or restrained eating behaviors, but subjects with obesity scored significantly higher for reported emotional eating.

DISCUSSION

Differences in preferences for listed common foods exist between weight status groups according to taste, food group, and texture. Consumers can make textural descriptions of foods that could be used to assess sensory and hedonic qualities of actual food choices.

Preferential fat intake increases adiposity but not body weight in Sprague-Dawley rats

It is not known whether an inherent preference for dietary fat promotes obesity in animals allowed to self-select the proportions of fat and carbohydrate consumed. To address this question, Sprague-Dawley rats were given a choice between two diets containing either 78% fat (by energy) or 78% carbohydrate; both diets were equicaloric for protein (22%). The entire study lasted 12 weeks. After an adaptation period, macronutrient preferences were determined by measuring 24 h intake of the two diets for 5 days; fat-preferring animals were classified as those that consumed greater than 60% of total energy from the fat/protein source, and carbohydrate-preferring rats as those that consumed less than 40%. Rats with intermediate macronutrient intakes were excluded. Initial body weight was not different between preference groups. Caloric intakes and body weights were then recorded at approximate weekly intervals, and fat depots were weighed at the time of sacrifice. Measures of energy intake and body weight did not differ between the two preference groups over time. In addition, baseline macronutrient preferences remained stable across the study period. Despite similar body weights, mean epididymal fat depot weight was significantly higher in fat-preferring rats than in carbohydrate-preferring rats (12.6 vs. 10.0 g); also, mean inguinal fat depot weight in fat-preferrers was greater although not reliably different compared to carbohydrate-preferring rats (12.9 vs. 10.9 g). Thus, the preferential intake of fat led to a greater deposition of both subcutaneous and visceral fat without an increase in body weight. These data lead us to conclude that the increased fat deposition was due primarily to the ingestion of fat rather than to excess caloric intake.