Gareth R. Dutton

Myths, Presumptions, and Facts about Obesity

BACKGROUND Many beliefs about obesity persist in the absence of supporting scientific evidence (presumptions); some persist despite contradicting evidence (myths). The promulgation of unsupported beliefs may yield poorly informed policy decisions, inaccurate clinical and public health recommendations, and an unproductive allocation of research resources and may divert attention away from useful, evidence-based information. METHODS Using Internet searches of popular media and scientific literature, we identified, reviewed, and classified obesity-related myths and presumptions. We also examined facts that are well supported by evidence, with an emphasis on those that have practical implications for public health, policy, or clinical recommendations. RESULTS We identified seven obesity-related myths concerning the effects of small sustained increases in energy intake or expenditure, establishment of realistic goals for weight loss, rapid weight loss, weight-loss readiness, physical-education classes, breast-feeding, and energy expended during sexual activity. We also identified six presumptions about the purported effects of regularly eating breakfast, early childhood experiences, eating fruits and vegetables, weight cycling, snacking, and the built (i.e., human-made) environment. Finally, we identified nine evidence-supported facts that are relevant for the formulation of sound public health, policy, or clinical recommendations. CONCLUSIONS False and scientifically unsupported beliefs about obesity are pervasive in both scientific literature and the popular press. (Funded by the National Institutes of Health.).

Validation of the Beck Depression Inventory-II in a Low-Income African American Sample of Medical Outpatients.

The psychometric properties of the Beck Depression Inventory-II (BDI-II) are well established with primarily Caucasian samples. However, little is known about its reliability and validity with minority groups. This study evaluated the psychometric properties of the BDI-II in a sample of low-income African American medical outpatients (N=220). Reliability was demonstrated with high internal consistency (.90) and good item-total intercorrelations. Criterion-related validity was demonstrated. A confirmatory factor analysis supported a hierarchical factor structure in which the BDI-II reflected 2 first-order factors (Cognitive and Somatic) that in turn reflected a second-order factor (Depression). These results are consistent with previous findings and thus support the use of the BDI-II in assessing depressive symptoms for African American patients in a medical setting.

Impact of intensive lifestyle intervention on depression and health-related quality of life in type 2 diabetes: the Look AHEAD Trial.

OBJECTIVE We examined the effects of an intensive lifestyle intervention (ILI), compared with a diabetes support and education (DSE) control intervention, on long-term changes in depression symptoms, antidepressant medication (ADM) use, and health-related quality of life (HRQoL) in overweight/obese individuals with type 2 diabetes. RESEARCH DESIGN AND METHODS Look AHEAD was a multisite randomized controlled trial of 5,145 overweight/obese participants assigned to ILI (designed to produce weight loss) or DSE and followed for a median of 9.6 years. The Beck Depression Inventory (BDI) was administered at baseline, annually at years 1–4, and again at year 8. Mean BDI scores and incidence of BDI scores ≥10, indicative of likely mild or greater depression, were examined. Annually through year 10, participants reported their ADM use and completed the Medical Outcomes Study Short Form 36 (SF-36) questionnaire, which yields physical component summary (PCS) and mental component summary (MCS) scores. RESULTS ILI significantly reduced the incidence of mild or greater depression symptoms (BDI scores ≥10) compared with DSE (hazard ratio [HR] = 0.85; 95% CI 0.75–0.97; P = 0.0145). Although SF-36 PCS scores worsened over time in both groups, ILI participants reported better physical function than DSE throughout the first 8 years (all P values <0.01). There were no significant differences between treatment arms in the proportion of participants who used ADMs or in SF-36 MCS scores. CONCLUSIONS ILI for overweight/obese patients with type 2 diabetes may reduce the risk of developing clinically significant symptoms of depression and preserve physical HRQoL. These findings should be considered when evaluating the potential benefits of ILIs.

A primary care weight management intervention for low-income African-American women.

Objective: To determine whether a tailored weight management program, addressing the needs of obese, low‐income African‐American women, would produce greater weight loss than standard medical care.

High trait self-control predicts positive health behaviors and success in weight loss

Surprisingly few studies have explored the intuitive connection between self-control and weight loss. We tracked participants’ diet, exercise and weight loss during a 12-week weight loss program. Participants higher in self-control weighed less and reported exercising more than their lower self-control counterparts at baseline. Independent of baseline differences, individuals high in dispositional self-control ate fewer calories overall and fewer calories from fat, burned marginally more calories through exercise, and lost more weight during the program than did those lower in self-control. These data suggest that trait self-control is, indeed, an important predictor of health behaviors.

Weight Loss Maintenance Following a Primary Care Intervention for Low-income Minority Women

Although the primary care setting offers an innovative option for weight loss interventions, there is minimal research examining this type of intervention with low‐income minority women. Further, there is a lack of research on the long‐term effects of these programs. The purpose of this investigation was to examine the weight loss maintenance of low‐income African‐American women participating in a primary care weight management intervention. A randomized controlled trial was conducted with overweight and obese women (N = 144) enrolled at two primary care clinics. Women received a 6‐month tailored weight loss intervention delivered by their primary care physician and completed follow‐up assessments 9, 12, and 18 months following randomization. The weight loss maintenance of the tailored intervention was compared to a standard care comparison group. The weight loss of intervention participants (−1.52 ± 3.72 kg) was significantly greater than that of standard care participants (0.61 ± 3.37 kg) at month 9 (P = 0.01). However, there was no difference between the groups at the 12‐month or 18‐month follow‐ups. Participants receiving a tailored weight loss intervention from their physician were able to maintain their modest weight loss up to 3–6 months following treatment. Women demonstrated weight regain at the 18‐month follow‐up assessment, suggesting that more intensive follow‐up in the primary care setting may be needed to obtain successful long‐term weight loss maintenance.

Is physical activity a gateway behavior for diet? Findings from a physical activity trial

OBJECTIVE While cross-sectional research indicates physical inactivity and poor diet tend to co-occur, there are limited longitudinal data on how interventions targeting one behavior affect other behaviors. The current investigation examined cross-sectional and longitudinal relationships between health behaviors within the context of a physical activity (PA) intervention. METHODS Sedentary women (n=280; mean age=47.1; 94.6% Caucasian) were enrolled in a randomized controlled PA trial comparing the effects of print-based, individually-tailored and gender-targeted PA interventions to a wellness/control condition. Women completed baseline, month 3, and month 12 assessments that included measures of PA and dietary behaviors. RESULTS Participants in more advanced PA stages of change reported significantly greater fruits/vegetables consumption than participants in less advanced stages, although the relationships between diet and minutes of weekly activity were less pronounced. The tailored and targeted print-based PA interventions had no effect on fruit/vegetable intake, although significant reductions in fat intake were observed from baseline (M=31.24%) to month 3 (M=30.41%), p<0.03; and baseline to month 12 (M=30.36%), p<0.01. Changes in PA were not predictive of improvements in eating behaviors. CONCLUSIONS Although fat intake decreased in the context of this PA intervention, fruit/vegetable intake remained unchanged. Also, PA did not serve as a gateway behavior for dietary improvements. In fact, improvements in activity were associated with increases rather than decreases in fat intake.

Weighing the Evidence of Common Beliefs in Obesity Research

Obesity is a topic on which many views are strongly held in the absence of scientific evidence to support those views, and some views are strongly held despite evidence to contradict those views. We refer to the former as “presumptions” and the latter as “myths.” Here, we present nine myths and 10 presumptions surrounding the effects of rapid weight loss; setting realistic goals in weight loss therapy; stage of change or readiness to lose weight; physical education classes; breastfeeding; daily self-weighing; genetic contribution to obesity; the “Freshman 15”; food deserts; regularly eating (versus skipping) breakfast; eating close to bedtime; eating more fruits and vegetables; weight cycling (i.e., yo-yo dieting); snacking; built environment; reducing screen time in childhood obesity; portion size; participation in family mealtime; and drinking water as a means of weight loss. For each of these, we describe the belief and present evidence that the belief is widely held or stated, reasons to support the conjecture that the belief might be true, evidence to directly support or refute the belief, and findings from randomized controlled trials, if available. We conclude with a discussion of the implications of these determinations, conjecture on why so many myths and presumptions exist, and suggestions for limiting the spread of these and other unsubstantiated beliefs about the obesity domain.

Weight change in the first 2 months of a lifestyle intervention predicts weight changes 8 years later

Examine the relationship between 1‐ and 2‐month weight loss (WL) and 8‐year WL among participants enrolled in a lifestyle intervention.

Evaluation of early weight loss thresholds for identifying nonresponders to an intensive lifestyle intervention

Weight losses in lifestyle interventions are variable, yet prediction of long‐term success is difficult. The utility of using various weight loss thresholds in the first 2 months of treatment for predicting 1‐year outcomes was examined.