Gregory J. Privitera

High fat diet intake during pre and periadolescence impairs learning of a conditioned place preference in adulthood

BackgroundBrain regions that mediate learning of a conditioned place preference (CPP) undergo significant development in pre and periadolescence. Consuming a high fat (HF) diet during this developmental period and into adulthood can lead to learning impairments in rodents. The present study tested whether HF diet intake, consumed only in pre and periadolescence, would be sufficient to cause impairments using a CPP procedure.MethodsRats were randomly assigned to consume a HF or a low fat (LF) diet during postnatal days (PD) 21-40 and were then placed back on a standard lab chow diet. A 20-day CPP procedure, using HF Cheetos® as the unconditioned stimulus (US), began either the next day (PD 41) or 40 days later (PD 81). A separate group of adult rats were given the HF diet for 20 days beginning on PD 61, and then immediately underwent the 20-day CPP procedure beginning on PD 81.ResultsPre and periadolescent exposure to a LF diet or adult exposure to a HF diet did not interfere with the development of a HF food-induced CPP, as these groups exhibited robust preferences for the HF Cheetos® food-paired compartment. However, pre and periadolescent exposure to the HF diet impaired the development of a HF food-induced CPP regardless of whether it was assessed immediately or 40 days after the exposure to the HF diet, and despite showing increased consumption of the HF Cheetos® in conditioning.ConclusionsIntake of a HF diet, consumed only in pre and periadolescence, has long-lasting effects on learning that persist into adulthood.

Proximity and Visibility of Fruits and Vegetables Influence Intake in a Kitchen Setting Among College Students

The hypothesis that participants will eat more fruits (apple slices) and vegetables (carrot cuts) if they are made more proximate and visible was tested using a 2 × 2 between-participants design. Proximity was manipulated by placing fruits and vegetables in a bowl at a table where participants sat (near) or 2 m from the table (far). Visibility was manipulated by placing fruits and vegetables in an opaque bowl that was covered (not visible) or in a clear bowl that was open (visible). The results showed that placing apple slices and carrot cuts in closer proximity to participants increased intake of these healthy foods. Making these foods more visible increased intake of apple slices but not carrot cuts, possibly because fruits taste sweet and so may be more motivationally salient than bitter-tasting carrots. Regardless, these data are the first to demonstrate experimentally that the proximity and visibility of fruits and vegetables can influence intake of these foods.

From weight loss to weight gain: appetite changes in major depressive disorder as a mirror into brain-environment interactions.

A SHIFT IN THE APPETITIVE SYMPTOMS OF DEPRESSION In recent decades, there has been a profound shift in the appetitive characteristics of depression. For early measures of depression, such as the Hamilton Rating Scale for Depression (HRSD; Hamilton, 1960), the key appetitive characteristic of depression was weight loss. In the 1950s and 60s, reduced appetite was considered a key feature even in mild depression and it was noted that in moderate depression the desire for food may almost totally disappear (Beck, 1967); those suffering with severe depression may almost have to force themselves to eat (Schuyler, 1974; Polivy and Herman, 1976). Zung, another pioneer of depression measurement, found that even the individual designated as the significant “other” associated loss of appetite as symptomatic of depression in the patient (Zung et al., 1974). No assessment for increased appetite, food intake, or weight gain was assessed in the HRSD. In these early reports, people with depression who overate or gained weight were diagnosed with “atypical depression” and were treated differently than those with more “typical” depression characterized by weight loss. Yet, this understanding of depression has shifted, with weight gain and increased appetite being identified as a “typical” symptom of depression among those with the disorder today (Doraiswamy, 2013), as is also evident as a common symptom for many other disorders involving emotional distress (American Psychological Association, 2013). Indeed, a recent representative US national survey of 43,093 adults found that the prevalence of major depression with atypical features was almost 40% higher than that of depression without atypical features (Blanco et al., 2012). In this survey, factors that predicted atypical depression appear to mirror the growth of obesity and over eating in our society as a whole.

Proximity of foods in a competitive food environment influences consumption of a low calorie and a high calorie food

The objective of this study was to test if proximity of a food or preference for a food influences food intake in a competitive food environment in which one low calorie/low fat (apple slices) and one higher calorie/higher fat (buttered popcorn) food was available in the same environment. The proximity of popcorn and apple slices was manipulated and 56 participants were randomly assigned to groups. In Group Apples Near, apple slices were placed near (within arms reach) a participant and popcorn was placed far (2m away). In Group Popcorn Near, buttered popcorn was placed near and apple slices were placed far. As a control for the absence of a proximity manipulation, Group Both Near had both test foods placed near. Although participants rated the popcorn as more liked than apples, the food that was placed closer to the participant was consumed most in the two experimental groups, regardless of preference (R(2)=0.38). Total energy intake was reduced most when popcorn was placed far from a participant compared to when it was placed near (R(2)=0.24). The effects reported here were not moderated by BMI and did not vary by sex. In all, the results support the hypothesis that making a low calorie food more proximate will reduce total energy intake and increase intake of a low calorie food, even when a higher calorie and more preferred food is also available, but less proximate.

Eat now or later: self-control as an overlapping cognitive mechanism of depression and obesity.

While overlapping neurobiological mechanisms are known, relatively little is known about how “self-control” and cognitive affective processing of rewards may also influence the bi-directional risk between obesity and depression. The objective of this study was to identify the extent to which “self-control,” measured using a delay discounting task is co-related to BMI and Depression diagnostic thresholds. A within-subjects counterbalanced design was used in which 92 participants (Mean±SD: BMI = 27.9±3.5, HAMD = 14.7±7.7) completed a series of clinical diagnostic, survey, and demographic questionnaires in a behavioral health laboratory setting. For the delay discounting task, participants chose between one large delayed reward and one successively smaller immediate reward for four food types (dessert, fried food, fruit, and vegetable). Results showed that delay discounting scores were predictive of BMI and depression with lower delay discounting scores associated with higher BMI and HAMD for the dessert (HAMD scores (β = -.197, p = .013), BMI (β = -.239, p < .001)) and fried food (HAMD scores (β = -.328, p = .001), BMI (β = -.166, p = .027)). Clinical significance was further evident when HAMD and BMI scores were converted to diagnostic thresholds. Only depression and/or atypical depressive symptoms were related to delay discounting scores with the fruit and vegetable. Thus, reduced cognitive affective self-control for impulsive food choices—particularly for “comfort foods” high in fat and sugar—appears to be a shared cognitive mechanism for both conditions perhaps contributing to the high prevalence of co-morbid mood disorders and weight gain.

The influence of eating rate on satiety and intake among participants exhibiting high dietary restraint.

Background Studies show inconsistent results with regards to whether eating slower can enhance satiety and reduce intake in a meal. Some methodological differences are apparent and could potentially explain why results are not consistent across studies. Objective To determine whether eating slower can enhance satiety and reduce intake when rate of eating is manipulated and not manipulated in a kitchen setting using a sample of participants who exhibit high dietary restraint (HDR). Design Two samples of college students who exhibit HDR, which is a group likely to use behavioral strategies to manage intake, were selected in a prescreening session. Participants were told how fast or slow to eat (Variation 1) or allowed to eat at their own pace (Variation 2). Self-reported satiety during the meal and amount consumed was recorded. The types of foods, macronutrient intakes, weights of foods, order of food intakes, and the dimensions of foods were held constant between groups to control for group differences in the sensory and hedonic qualities of the meals. Results Eating slower enhanced mid-meal satiety ratings, but only when instructions were given to eat fast or slow (Variation 1). In both variations, eating slower did not reduce amount consumed in the meal, although each variation had sufficient power to detect differences. Conclusion Eating slower is not likely to be an effective strategy to control intake in a meal among those exhibiting HDR.

Randomized Feedback About Diagnosis Influences Statistical and Clinical Significance of Self-Report ADHD Assessment in Adults

Objective: An experiment was conducted to test the hypothesis that feedback about an ADHD diagnosis influences how a nonclinical sample scores on the Adult ADHD Self-Report Scale (ASRS) screener. Method: A total of 54 participants who scored below clinical significance on the ASRS in a pretest, that is, marked fewer than 4 of 6 items found to be most predictive of symptoms consistent with clinical diagnosis of adult ADHD, completed the assessment again 1 week later in a posttest with “negative,” “positive,” or no feedback written on the posttest to indicate how participants scored on the pretest. Results: In all, 8 of 10 participants who scored in the clinical significance range for ADHD in the posttest were those who received positive feedback. Scores for the positive feedback group increased most from pretest to posttest for inattentive domain items (R2 = .19). Conclusion: Patient beliefs prior to a diagnostic screening can influence ASRS self-report ratings.

Emolabeling increases healthy food choices among grade school children in a structured grocery aisle setting

Health literacy, the ability to acquire health-related knowledge and make appropriate health-related decisions, is regarded as a key barrier to meaningfully convey health information to children and can impact food choice. Emolabeling is an image-based labeling strategy aimed at addressing this problem by conveying health information using emotional correlates of health using emoticons (happy = healthy; sad = not healthy). To test the utility of such a method to promote healthy food choices among children, 64 children (59% girls, <5% non-White, mean BMI = 52nd percentile) in kindergarten through 5th grade were first given a brief 5-min lesson on how to use the emoticons, then asked to choose any 4 foods in each of 2 aisles structured to mimic a grocery aisle - there were 12 identical foods placed in the same location in each aisle with half being low calorie and half high calorie snacks. Foods were emolabeled in one aisle; no emolabels were used in the other aisle; the order that children were brought in each aisle was counterbalanced. Results showed that adding emolabels increased the number (M ± SD) of healthy foods chosen (3.6 ± 0.7 with vs. 2.3 ± 1.1 without emolabels present [95% CI 1.0, 1.5], R(2) = .67) and reduced the total calories (M ± SD) of foods chosen (193.5 ± 88.5 Cal with vs. 374.3 ± 152.6 Cal without emolabels present [95% CI -212.6, -149.0], R(2) = .70). Hence, adding emolabels was associated with healthier food choices among children, thereby demonstrating one possible strategy to effectively overcome health literacy barriers at these ages.

The Effectiveness of "Emolabeling" to Promote Healthy Food Choices in Children Preschool Through 5th Grade

Obesity has become a growing global concern. Evidence indicates that ecological factors are most predictive of obesity among children, and that a new strategy, referred to as emolabeling, may effectively address ecological factors, although the extent to which it can influence food choice is not yet known, but tested here. Specifically, we tested the hypothesis that children aged 3 to 11 years will use emolabels, or emotional correlates of health (i.e. healthy-happy, unhealthy-sad), to make healthy food choices. A cross-sectional design was used with two phases. In Phase 1, children were taught how to use emolabels with a “faces of health” lesson. In Phase 2, children made choices between containers that were laid out on a large table in pairs and varied by taste (tastes good, no information), social norms (popular, not popular), branding (image of a minion, no image), or preference (told what food was in each container). A control pair was labeled with only emoticons. The order and presentation of the containers were counterbalanced for each variation. Results showed that a significant proportion of children in the pre-literacy and the early literacy grades used emoticons to specifically make healthy food choices in each variation ( p < .05 for all tests), except when children were told what foods were in the containers. In all, emolabeling effectively influenced food choices for healthy foods among children aged 3 to 11 years, more so than labeling for taste, social norms, and branding, but not preference.

An assessment of liking for sugars using the estimated daily intake scale.

Sugar is often used in learning and conditioning studies as an unconditioned stimulus (US) to enhance liking for a flavor mixed with it. To use sugar as a US, participants are selected only if they like the taste of sugar based on their ratings of a sweetened water US during a preexposure trial prior to experimental procedures. This US-only trail introduces a potential sensory bias and can lead to participant attrition when such a trial is conducted the day prior to experimental procedures. The aim of the present study was to construct a brief scale, called the Estimated Daily Intake Scale for Sugar (EDIS-S), to measure a participants exposure to sugar in their diet. It was hypothesized that exposure to sugar would be positively correlated with liking for sugar. As expected, an 11-item EDIS-S was reliable and significantly correlated with ratings of liking for a sweetened taste solution. Implications for the use of the EDIS-S as an assessment in many areas of research, and as a participant selection tool for conditioning studies are discussed.