Relationship between eating rates and obesity

Transient Intermittent Hyperglycemia Accelerates Atherosclerosis by Promoting Myelopoiesis

RATIONALE

Treatment efficacy for diabetes mellitus is largely determined by assessment of HbA1c (glycated hemoglobin A1c) levels, which poorly reflects direct glucose variation. People with prediabetes and diabetes mellitus spend >50% of their time outside the optimal glucose range. These glucose variations, termed transient intermittent hyperglycemia (TIH), appear to be an independent risk factor for cardiovascular disease, but the pathological basis for this association is unclear.

OBJECTIVE

To determine whether TIH per se promotes myelopoiesis to produce more monocytes and consequently adversely affects atherosclerosis.

METHODS AND RESULTS

To create a mouse model of TIH, we administered 4 bolus doses of glucose at 2-hour intervals intraperitoneally once to WT (wild type) or once weekly to atherosclerotic prone mice. TIH accelerated atherogenesis without an increase in plasma cholesterol, seen in traditional models of diabetes mellitus. TIH promoted myelopoiesis in the bone marrow, resulting in increased circulating monocytes, particularly the inflammatory Ly6-C^hi subset, and neutrophils. Hematopoietic-restricted deletion of S100a9, S100a8, or its cognate receptor Rage prevented monocytosis. Mechanistically, glucose uptake via GLUT (glucose transporter)-1 and enhanced glycolysis in neutrophils promoted the production of S100A8/A9. Myeloid-restricted deletion of Slc2a1 (GLUT-1) or pharmacological inhibition of S100A8/A9 reduced TIH-induced myelopoiesis and atherosclerosis.

CONCLUSIONS

Together, these data provide a mechanism as to how TIH, prevalent in people with impaired glucose metabolism, contributes to cardiovascular disease. These findings provide a rationale for continual glucose control in these patients and may also suggest that strategies aimed at targeting the S100A8/A9-RAGE (receptor for advanced glycation end products) axis could represent a viable approach to protect the vulnerable blood vessels in diabetes mellitus. Graphic Abstract: A graphic abstract is available for this article.

A description of an 'obesogenic' eating style that promotes higher energy intake and is associated with greater adiposity in 4.5year-old children: Results from the GUSTO cohort

Recent findings confirm that faster eating rates support higher energy intakes within a meal and are associated with increased body weight and adiposity in children. The current study sought to identify the eating behaviours that underpin faster eating rates and energy intake in children, and to investigate their variations by weight status and other individual differences. Children (N=386) from the Growing Up in Singapore towards Healthy Outcomes (GUSTO) cohort took part in a video-recorded ad libitum lunch at 4.5years of age to measure acute energy intake. Videos were coded for three eating behaviours (bites, chews and swallows) to derive a measure of eating rate (g/min) and measures of eating microstructure: eating rate (g/min), total oral exposure (min), average bite size (g/bite), chews per gram, oral exposure per bite (s), total bites and proportion of active to total mealtime. Children's BMIs were calculated and a subset of children underwent MRI scanning to establish abdominal adiposity. Children were grouped into faster and slower eaters, and into healthy and overweight groups to compare their eating behaviours. Results demonstrate that faster eating rates were correlated with larger average bite size (r=0.55, p<0.001), fewer chews per gram (r=-0.71, p<0.001) and shorter oral exposure time per bite (r=-0.25, p<0.001), and with higher energy intakes (r=0.61, p<0.001). Children with overweight and higher adiposity had faster eating rates (p<0.01) and higher energy intakes (p<0.01), driven by larger bite sizes (p<0.05). Eating behaviours varied by sex, ethnicity and early feeding regimes, partially attributable to BMI. We propose that these behaviours describe an 'obesogenic eating style' that is characterised by faster eating rates, achieved through larger bites, reduced chewing and shorter oral exposure time. This obesogenic eating style supports acute energy intake within a meal and is more prevalent among, though not exclusive to, children with overweight. Clinical Trial Registry Number: NCT01174875; https://clinicaltrials.gov/.

Chewing after stress: psychosocial stress influences chewing frequency, chewing efficacy, and appetite

BACKGROUND

Psychosocial stress is accompanied by an increase in the activity of the hypothalamic-pituitary-adrenocortical (HPA)-axis and by an increase in food intake. At present, no studies have been conducted to examine the impact of a potent laboratory stress test on the chewing frequency.

METHODS

Thirty-one healthy participants (14 females, mean age 27.13) were compared after they had fulfilled the protocol of a standardized psychosocial stress test, the Trier Social Stress Test (TSST), and after a resting condition of silent reading in reference to their chewing frequency, chewing efficacy, food intake, and eating preferences. As part of the design free salivary cortisol levels and heart rate variability were measured repeatedly before and after the TSST and the resting condition.

RESULTS

After the TSST, the participants exhibited a significantly higher mean chewing frequency than after the resting condition (F(2,60)=3.600, p=.035, η(2)=.107). The testing condition had no influence on the amount of food intake. Following the psychosocial stress, however, the participants reported a significantly less general appetite (Z=-3.921, p<.001) and less of an appetite for eggs (Z=-2.023, p=.043) than after their resting condition. No correlation was found between the salivary cortisol response and the chewing frequency.

CONCLUSION

The results indicated that psychosocial stress is associated with an increase in chewing frequency, as measured with a sound-based apparatus, and with a decrease in appetite.

Do Obese Eat Faster Than Lean Subjects? Food Intake Studies in Pima Indian Men

Food intake rate has previously been derived from observation of eating behavior in laboratory settings or in public eating establishments. Although it has been suggested that obese individuals eat faster than lean individuals, observations of such an "obese eating style" have yielded mixed results. In the present study, the relationship between ad-libitum food intake rate and obesity was evaluated over 4 days on a metabolic ward in 28 healthy Pima Indian men (Mean +/- SD; 29 +/- 7 y, 100.4 +/- 27.1 kg, 33 +/- 10% body fat) using an automated food selection system containing a large variety of foods. Total energy intake averaged 18829 +/- 3299 kJ/d consisting of 47 +/- 4, 40 +/- 3, and 13 +/- 1 percent of carbohydrate, fat and protein, respectively. The average meal duration was 25 +/- 7 min. Food intake rate was 68 +/- 21 g/min while carbohydrate, fat and protein intake rates were 23 +/- 6, 9 +/- 3 and 6 +/- 2 g/min, respectively. Food intake rate correlated negatively with % body fat (r = -0.61, P < 0.01). Similar relationships were found between the intake rates of carbohydrate, fat and protein and body fatness. Only prospective studies will indicate whether a slow food intake rate may contribute to the etiology of obesity by possibly reducing satiety.

Eating behaviour and retro-nasal aroma release in normal-weight and overweight adults: a pilot study

Eating rate and bite size are important factors affecting food intake, and we hypothesise the underlying role of oral sensory exposure in this. However, the latter currently lacks objective measuring parameters, but an interesting measure could be the extent of in vivo retro-nasal aroma release. Second, the literature is ambiguous about overweight subjects differing from normal-weight subjects in eating behaviour. Consequently, we investigated: (1) whether eating behaviour (food intake, eating rate, bite size, number of bites and meal duration) relates to weight status and (2) whether the extent of retro-nasal aroma release relates to eating behaviour and weight status. A matched group (sex, age and dietary restraint) of twenty-seven normal-weight (BMI 21.8 (SD 1.6) kg/m2) and twenty-seven overweight/obese subjects (BMI 30.5 (SD 5.8) kg/m2) consumed a spiced rice meal and apple pie yogurt on separate test days. The extent of retro-nasal aroma release was measured on a third test day. Mean bite size for spiced rice was significantly (P = 0.03) larger in overweight/obese (10.3 (SD 3.2) g) v. normal-weight subjects (8.7 (SD 2.1) g). There were no other significant differences in eating behaviour or retro-nasal aroma release between the groups. Eating behaviours were not correlated with BMI or retro-nasal aroma release. Subjects showed consistent eating behaviour for both test products. Eating behaviour might be a characteristic of an individual but not by definition a characteristic for a group of people based on their weight. Given the large sample sizes, necessary according to a posteriori sample size calculations, one needs to consider the relevance of finding a statistically significant difference in eating behaviour between the weight groups in a laboratory setting.

Eating behavior and obesity at Chinese buffets

The aim of this study was to investigate whether the eating behaviors of people at all-you-can-eat Chinese buffets differs depending upon their body mass. The resulting findings could confirm or disconfirm previous laboratory research that has been criticized for being artificial.

METHODS AND PROCEDURES

Trained observers recorded the height, weight, sex, age, and behavior of 213 patrons at Chinese all-you-can-eat restaurants. Various seating, serving, and eating behaviors were then compared across BMI levels.

RESULTS

Patrons with higher levels of BMI were more likely to be associated with using larger plates vs. smaller plates (OR 1.16, P < 0.01) and facing the buffet vs. side or back (OR 1.10, P < 0.001). Patrons with higher levels of BMI were less likely to be associated with using chopsticks vs. forks (OR 0.90,P < 0.05), browsing the buffet before eating vs. serving themselves immediately (OR 0.92, P < 0.001), and having a napkin on their lap vs. not having a napkin on their lap (OR 0.92, P < 0.01). Patrons with lower BMIs left more food on their plates (10.6% vs. 6.0%, P < 0.05) and chewed more per bite of food (14.8 vs. 11.9, P < 0.001).

DISCUSSION

These observational findings of real-world behavior provide support for laboratory studies that have otherwise been dismissed as artificial.

Eating slowly led to decreases in energy intake within meals in healthy women

Although reducing eating rate is frequently advocated for control of food intake and thus body weight, empirical evidence is extremely limited and inconsistent. We sought to compare the impact of slow and quick eating rates on development of satiation in healthy women. In a randomized design, 30 healthy women (22.9+/-7.1 years; body mass index [calculated as kg/m(2)] 22.1+/-2.9) were studied on two test visits to compare slow and quick eating rates. Satiation was examined as the main outcome, using the objective measure of energy intake during ad libitum meals. At designated times, subjects also rated perceived hunger, satiety, desire to eat, thirst and meal palatability on visual analogue scales. Slow rates of ingestion led to significant decreases in energy intake (quick: 645.7+/-155.9 kcal; slow: 579.0+/-154.7 kcal; P<0.05) and significant increases in water consumption (quick: 289.9+/-155.1 g; slow: 409.6+/-205.8 g; P<0.05). Despite higher energy intake upon meal completion under the quick condition, satiety was significantly lower than the slow condition (P<0.05). Accordingly, the quick condition showed a lower Satiating Efficiency Index (quick: 0.1; slow: 0.2; P<0.05). After meal completion, pleasantness ratings tended to be higher under the slow condition (P=0.04; but not significant after Bonferroni adjustment). Ad libitum energy intake was lower when the meal was eaten slowly, and satiety was higher at meal completion. Although more study is needed, these data suggest that eating slowly may help to maximize satiation and reduce energy intake within meals.

Coping with dietary relapse crises and their aftermath

We examined dieters' attempts to cope with dietary relapse crises (Immediate coping) and their aftermath (Restorative coping). We analyzed posttreatment interviews with 57 obese subjects with Type-II diabetes, comparing coping in situations in which subjects lapsed with those in which they survived temptations to overeat. Performance of Immediate coping predicted survival but the particular type of coping made little difference. Eight types of Immediate cognitive coping were equally associated with survival: each was significantly more effective than no coping and equal to the aggregate of the other types. A similar pattern held for 5 types of Immediate behavioral coping, except that social support was no more effective than no coping and restraint was less effective than the other types. Restorative behavioral coping was elicited as a response to overeating, while Restorative cognitive coping seemed elicited by the negative thoughts and feelings that sometimes accompany lapses or temptations. Implications for treatment and future research on relapse crises and coping are discussed.

Influence of early feeding style on adiposity at 6 years of age

In a previous study we found that a vigorous infant feeding style measured in the laboratory at 2 and 4 weeks of age predicted the degree of adiposity at 1 and 2 years of age. A follow-up of this cohort of infants at 3 and 6 years of age is now reported. Factors predicting adiposity, measured by body mass index at 3 years of age, were pressure of suckling, with high-pressure sucking (denoting a vigorous feeding style) associated with greater adiposity, and time of introduction of solid food, with delayed introduction of solid food or breast-feeding longer than 5 months, or both, being associated with greater adiposity. Predictive factors at 6 years of age were adiposity at birth, with greater adiposity at birth predicting greater fatness at 6 years, parental education, with less education associated with fatness, and a prolonged period of breast-feeding with delayed introduction of solid food. These factors accounted for 40.4% of the variance in adiposity at 3 years of age and 31.2% at 6 years. The effects of social learning on body mass index, indicated by parental educational level, appear to strengthen over time, whereas the effects of the vigorous feeding style wane.

Development of eating behavior and its relation to physical growth in normal weight preschool children

In order to examine whether some characteristics of eating behavior are related to physical growth and weight increment in young children, a longitudinal prospective study was conducted. The eating behaviors of 11 age-matched normal-weight preschool children were observed at lunchtime on 18 consecutive days. The same set of observations was carried out three times when the children were 40, 52 and 59 months old, on average. MANOVA procedures for repeated measures design revealed that the eating behavior of the subjects changed considerably between the first and second observation stages, whereas it did not change significantly between the second and third stages. It was considered that eating behaviour developed mostly between the first and second observation stages and that the subjects were able to eat completely independently by the second observation stage. The increment in the children's weight per month began to show individual variation at the age of 48 months between the first and second observation stages. Coincidentally, the relationship between eating behavior and physique first appeared at the second observation stage and a similar relationship was observed at the third stage. The partial correlation coefficients and the multivariate multiple regression of MANOVA were performed for this analysis. Meal duration was the factor most strongly related to weight and BMI, whereas in contrast, growth history and familial factors influenced the eating behavior at the first observation stage. The present results indicate that eating behavior was one of the factors related to the rapid increase in weight soon after or just at the time of initiation of complete self-feeding in normal-weight children.

Responses of lean and obese subjects to preloads, deprivation, and palatability

The effects of preloads, deprivation, and palatability on the eating behavior of non-dieting lean and obese subjects were studied during laboratory meals, using small solid food units (SFUs) to measure the rate of ingestion over the time-course of the meals. In both weight groups, rate of intake decreased from the beginning to the end of meals. The smaller the preloads and the longer the deprivation interval, the faster subjects ate at the beginning of meals and the higher their hunger ratings were. The longest deprivation interval also increased palatability ratings, meal length, and the total amount that subjects ate. Increasing the palatability of the food increased the rate of intake at the beginning of meals, meal length, and the amount of food that subjects ate. Obese subjects were more sensitive to palatability and less responsive to deprivation than lean subjects. For example, while lean subjects became less discriminating about the palatability of the food at the beginning of meals as deprivation increased, obese subjects did not. The satiation mechanism of obese subjects was also different from lean subjects. For example, obese subjects overate after preloads while lean subjects underate compared to their baselines.

Psychological features of obesity

The study of obesity from a variety of psychological perspectives has been exciting and inventive, although we still do not understand fully the role of psychological variables in the etiology of obesity. Many of the factors thought to be of etiologic significance--field dependence, lack of impulse control, inability to delay gratification, or a maladaptive eating style--have not been supported by experimental evidence. Other factors once thought to be of importance as causes of obesity, depression and dysphoria, for example, appear, instead, to be consequences of being obese and may serve to maintain and intensify weight-related problems. Dieting behavior in response to weight concerns appears, perversely, to be implicated in increasing overweight and adiposity. Finally, arousability in response to food cues in the environment may play a causal role in some obesities.

Eating style and food storage habits in the home. Assessment of obese and nonobese families

Two home observations of eating styles and food storage and food cues in eight obese and eight nonobese families were conducted. Obese and nonobese children and their respective obese and nonobese parents were observed at dinner time and assessed on several different eating behaviors. Observers also recorded foods visible in the home and foods found on the first shelves of the freezer, refrigerator, and the most frequently used cupboard. Results did not reveal a different eating style between obese and nonobese families, although obese daughters appeared to eat differently than nonobese daughters. There were also similarities and differences in eating behaviors between children and parents, independent of individuals' weight status. Caloric totals of food storage, visible foods, and calories consumed appeared to be higher in obese households at the first observation, although obese families reduced the quantity of visible foods, and food consumption at observation two. The validity of socially desirable behaviors collected from more than one observation period and implications of the variability of the target behaviors when assessing obese families' eating styles and food habits are discussed.

Reduction of rapid eating by normal adults

Three normal adults, who considered their eating habits socially unacceptable, were trained in the family home to eat at normal pace by gradually increasing their meal duration. Additional food, descriptive praise, and self-approval were made contingent upon a step-wise increasing criterion of meal duration. During maintenance, the additional food component was withdrawn. A multiple baseline experimental analysis showed that the treatment package was successful in decreasing rapid eating to normal rates, as measured by the subjects' self-monitoring of their meal durations. In addition, the increased durations were maintained when the food component was withdrawn from the treatment package in a subsequent phase.

Food choice and eating behavior among obese, lean, and normal individuals

The current study evaluates the food preferences and eating behavior of lean, normal, and obese subjects in a university cafeteria setting. Results showed that male leans did not differ from male normals in the proportion of calories derived from various food categories. Female leans ate proportionately less regular dairy but more fruit and dessert calories than female normals. Male obese ate more red meats and less fruit and dessert calories than male normals. Female obese showed the same patterns as female leans, consuming more desserts and fruit, but less regular dairy calories than female normals. Male leans also consumed less red meat and more dessert calories than male obese. No differences were found in total calories or menu items within sex and weight groups. Males, however, consumed more calories and chose more items than females. No differences were found among the groups in bite rate, sip rate, and total eating time. However, male and female leans engaged in significantly more noneating activity than their normal group and male obese ate significantly more calories/mouthful than all but the male leans. The results suggest that food choice, particularly saturated fat, may play a weaker role in the weight status of male lean and female obese subjects than in other groups, and that lean subjects are apt to find food and eating stimuli much less reinforcing than obese subjects. Results are discussed in terms of implications for treatment of obesity.

The effects of social setting, perceived weight category, and gender on eating behavior

Four hundred and sixteen male and 233 female subjects were observed in a university cafeteria at lunch time. They were categorized according to five perceived weight groups with category one being underweight and category five being overweight. The number of calories in the food bought for lunch by each subject was calculated and recorded. Males bought food containing more calories than females but for males the amount of calories did not differ by perceived weight category. Females purchased food with fewer calories than males but the heavier females bought food with higher caloric content.

Descriptive analysis of eating regulation in obese and nonobese children

Bite rate, sip rate, and concurrent activities of six 7-yr-old children, three obese and three nonobese, were observed at lunchtime over a six-month period. A procedure for decreasing bite rate, putting eating utensils down between bites, was implemented in a multiple-baseline across-subjects design. Sip rates and concurrent activities were observed to assess behavioral covariations. In addition, bite rate and amount of food completed were computed over six food categories to analyze food preferences. Results indicated the control of bite rate acorss all subjects, with a significant reduction in amount of food consumed. Correlations between the response classes indicated they were at least partially independent. Differences in eating behavior of obese and nonobese subjects were observed for breadstuffs and milk drinking.