Cheryl H. Gilhooly

Food cravings and energy regulation: the characteristics of craved foods and their relationship with eating behaviors and weight change during 6 months of dietary energy restriction

Objective:To examine characteristics of craved foods in relation to dietary energy restriction (ER) with high (HG) and low glycemic load (LG) diets.Design:Assessments of food cravings before and during a randomized controlled trial of HG and LG diets provided for 6 months.Subjects:Thirty-two healthy, overweight women aged 20–42 years.Measurements:Self-reported food cravings and dietary intake, body weight, weight history and measures of eating behaviors.Results:Foods craved at baseline were more than twice as high in energy density as the habitual diet (3.7±1.5 vs 1.7±0.3 kcal/g; P<0.001), and on average were lower in protein (P<0.001) and fiber (P<0.001) and higher in fat (P=0.002). There were no statistically significant changes in nutritional characteristics of craved foods after 6 months of ER. There was a significant relationship between reported portion size of craved food consumed at baseline and lifetime high body mass index (r=0.49, P=0.005). Additionally, there was a significant association between susceptibility to hunger and craving frequency at baseline, and there were significant relationships between hunger score, craving frequency, strength and percentage of time that cravings are given in to after 6 months of ER. In multiple regression models, subjects who lost a greater percentage of weight craved higher energy-dense foods at month 6 of ER, but also reported giving in to food cravings less frequently (adjusted R 2=0.31, P=0.009).Conclusion:High energy density and fat content, and low protein and fiber contents were identifying characteristics of craved foods. The relationships between craving variables and hunger score suggest that the relative influence of hunger susceptibility on cravings may be important before and especially after ER. Portion size of craved foods and frequency of giving in to food cravings appear to be important areas for focus in lifestyle modification programs for long-term weight loss.

The Effects of the Dietary Glycemic Load on Type 2 Diabetes Risk Factors during Weight Loss

Objective: To compare the effects of two calorie‐restricted diets that differ in glycemic load (GL) on glucose tolerance and inflammation.

Long-term effects of provided low and high glycemic load low energy diets on mood and cognition.

Energy-restricted low glycemic load diets are being used increasingly for weight loss. However, the long-term effects of such regimens on mood and cognitive performance are not known. We assessed the effects of low glycemic load (LG) and high glycemic load (HG) energy-restricted diets on mood and cognitive performance during 6 months of a randomized controlled trial when all food was provided. Subjects were 42 healthy overweight adults (age 35+/-5 years; BMI 27.8+/-1.6 kg/m(2)) with a mean weight loss of 8.7+/-5.0% that did not differ significantly by diet randomization. Mood was assessed by using the Profile of Mood States (POMS) questionnaire. Cognitive performance was assessed by using computerized tests of simple reaction time, vigilance, learning, short-term memory and attention, and language-based logical reasoning. Worsening mood outcome over time was observed in the HG diet group compared to the LG for the depression subscale of POMS (p=0.009 after including hunger as a covariate). There was no significant change over time in any cognitive performance values. These findings suggest a negative effect of an HG weight loss diet on sub-clinical depression but, in contrast to a previous suggestion, provide no support for differential effects of LG versus HD diets on cognitive performance.

Effect of Calorie Restriction on Mood, Quality of Life, Sleep, and Sexual Function in Healthy Nonobese Adults: The CALERIE 2 Randomized Clinical Trial

IMPORTANCE Calorie restriction (CR) increases longevity in many species and reduces risk factors for chronic diseases. In humans, CR may improve health span, yet concerns remain about potential negative effects of CR. OBJECTIVE To test the effect of CR on mood, quality of life (QOL), sleep, and sexual function in healthy nonobese adults. DESIGN, SETTING, AND PARTICIPANTS A multisite randomized clinical trial (Comprehensive Assessment of Long-term Effects of Reducing Intake of Energy Phase 2 [CALERIE 2]) was conducted at 3 academic research institutions. Adult men and women (N = 220) with body mass index (BMI; calculated as weight in kilograms divided by height in meters squared) of 22.0 to 28.0 were randomized to 2 years of 25% CR or an ad libitum (AL) control group in a 2:1 ratio favoring CR. Data were collected at baseline, 12 months, and 24 months and examined using intent-to-treat analysis. The study was conducted from January 22, 2007, to March 6, 2012. Data analysis was performed from July 18, 2012, to October 27, 2015. INTERVENTIONS Two years of 25% CR or AL. MAIN OUTCOMES AND MEASURES Self-report questionnaires were administered to measure mood (Beck Depression Inventory-II [BDI-II], score range 0-63, higher scores indicating worse mood, and Profile of Mood States [POMS], with a total mood disturbance score range of -32 to 200 and higher scores indicating higher levels of the constructs measured), QOL (Rand 36-Item Short Form, score range 0-100, higher scores reflecting better QOL, and Perceived Stress Scale, score range 0-40, higher scores indicating higher levels of stress), sleep (Pittsburgh Sleep Quality Index [PSQI], total score range 0-21, higher scores reflecting worse sleep quality), and sexual function (Derogatis Interview for Sexual Function-Self-report, total score range 24-188, higher scores indicating better sexual functioning). RESULTS In all, 218 participants (152 women [69.7%]; mean [SD] age, 37.9 (7.2) years; mean [SD] BMI, 25.1 [1.6]) were included in the analyses. The CR and AL groups lost a mean (SE) of 7.6 (0.3) kg and 0.4 (0.5) kg, respectively, at month 24 (P < .001). Compared with the AL group, the CR group had significantly improved mood (BDI-II: between-group difference [BGD], -0.76; 95% CI, -1.41 to -0.11; effect size [ES], -0.35), reduced tension (POMS: BGD, -0.79; 95% CI, -1.38 to -0.19; ES, -0.39), and improved general health (BGD, 6.45; 95% CI, 3.93 to 8.98; ES, 0.75) and sexual drive and relationship (BGD, 1.06; 95% CI, 0.11 to 2.01; ES, 0.35) at month 24 as well as improved sleep duration at month 12 (BGD, -0.26; 95% CI, -0.49 to -0.02; ES, -0.32) (all P < .05). Greater percent weight loss in the CR group at month 24 was associated with increased vigor (Spearman correlation coefficient, ρ = -0.30) and less mood disturbance (ρ = 0.27) measured with the POMS, improved general health (ρ = -0.27) measured with the SF-36, and better sleep quality per the PSQI total score (ρ = 0.28) (all P < .01). CONCLUSIONS AND RELEVANCE In nonobese adults, CR had some positive effects and no negative effects on health-related QOL. TRIAL REGISTRATION clinicaltrials.gov Identifier: NCT00427193.

Low or Moderate Dietary Energy Restriction for Long-term Weight Loss: What Works Best?

Theoretical calculations suggest that small daily reductions in energy intake can cumulatively lead to substantial weight loss, but experimental data to support these calculations are lacking. We conducted a 1‐year randomized controlled pilot study of low (10%) or moderate (30%) energy restriction (ER) with diets differing in glycemic load in 38 overweight adults (mean ± s.d., age 35 ± 6 years; BMI 27.6 ± 1.4 kg/m2). Food was provided for 6 months and self‐selected for 6 additional months. Measurements included body weight, resting metabolic rate (RMR), adherence to the ER prescription assessed using 2H218O, satiety, and eating behavior variables. The 10%ER group consumed significantly less energy (by 2H218O) than prescribed over 12 months (18.1 ± 9.8%ER, P = 0.04), while the 30%ER group consumed significantly more (23.1 ± 8.7%ER, P < 0.001). Changes in body weight, satiety, and other variables were not significantly different between groups. However, during self‐selected eating (6–12 months) variability in % weight change was significantly greater in the 10%ER group (P < 0.001) and poorer weight outcome on 10%ER was predicted by higher baseline BMI and greater disinhibition (P < 0.0001; adj R2 = 0.71). Weight loss at 12 months was not significantly different between groups prescribed 10 or 30%ER, supporting the efficacy of low ER recommendations. However, long‐term weight change was more variable on 10%ER and weight change in this group was predicted by body size and eating behavior. These preliminary results indicate beneficial effects of low‐level ER for some but not all individuals in a weight control program, and suggest testable approaches for optimizing dieting success based on individualizing prescribed level of ER.

Rationale and consequences of reclassifying obesity as an addictive disorder: Neurobiology, food environment and social policy perspectives

The rapid increase in the prevalence of obesity is a priority for investigators from across numerous disciplines, including biology, nutritional science, and public health and policy. In this paper, we systematically examine the premise that common dietary obesity is an addictive disorder, based on the criteria for addiction described in the Diagnostic and Statistical Manual (DSM) of Mental Disorders of the American Psychiatric Association, version IV, and consider the consequences of such a reclassification of obesity for public policy. Specifically, we discuss evidence from both human and animal studies investigating the effects of various types and amounts of food and the food environment in obese individuals. Neurobiological studies have shown that the hedonic brain pathways activated by palatable food overlap considerably with those activated by drugs of abuse and suffer significant deficits after chronic exposure to high-energy diets. Furthermore, food as a stimulus can induce the sensitization, compulsion and relapse patterns observed in individuals who are addicted to illicit drugs. The current food environment encourages these addictive-like behaviors where increased exposure through advertisements, proximity and increased portion sizes are routine. Taking lessons from the tobacco experience, it is clear that reclassifying common dietary obesity as an addictive disorder would necessitate policy changes (e.g., regulatory efforts, economic strategies, and educational approaches). These policies could be instrumental in addressing the obesity epidemic, by encouraging the food industry and the political leadership to collaborate with the scientific and medical community in establishing new and more effective therapeutic approaches.

Potassium Bicarbonate Supplementation Lowers Bone Turnover and Calcium Excretion in Older Men and Women: A Randomized Dose-Finding Trial

The acid load accompanying modern diets may have adverse effects on bone and muscle metabolism. Treatment with alkaline salts of potassium can neutralize the acid load, but the optimal amount of alkali is not established. Our objective was to determine the effectiveness of two doses of potassium bicarbonate (KHCO3) compared with placebo on biochemical markers of bone turnover, and calcium and nitrogen (N) excretion. In this double‐blind, randomized, placebo‐controlled study, 244 men and women age 50 years and older were randomized to placebo or 1 mmol/kg or 1.5 mmol/kg of KHCO3 daily for 3 months; 233 completed the study. The primary outcomes were changes in 24‐hour urinary N‐telopeptide (NTX) and N; changes in these measures were compared across the treatment groups. Exploratory outcomes included 24‐hour urinary calcium excretion, serum amino‐terminal propeptide of type I procollagen (P1NP), and muscle strength and function assessments. The median administered doses in the low‐dose and high‐dose groups were 81 mmol/day and 122 mmol/day, respectively. When compared with placebo, urinary NTX declined significantly in the low‐dose group (p = 0.012, after adjustment for baseline NTX, gender, and change in urine creatinine) and serum P1NP declined significantly in the low‐dose group (p = 0.004, adjusted for baseline P1NP and gender). Urinary calcium declined significantly in both KHCO3 groups versus placebo (p < 0.001, adjusted for baseline urinary calcium, gender, and changes in urine creatinine and calcium intake). There was no significant effect of either dose of KHCO3 on urinary N excretion or on the physical strength and function measures. KHCO3 has favorable effects on bone turnover and calcium excretion and the lower dose appears to be the more effective dose. Long‐term trials to assess the effect of alkali on bone mass and fracture risk are needed.

Long-Term Effects of Energy-Restricted Diets Differing in Glycemic Load on Metabolic Adaptation and Body Composition*

A randomized controlled trial of high glycemic load (HG) and low glycemic load (LG) diets with food provided for 6 months and self-administered for 6 additional months at 30% caloric restriction (CR) was performed in 29 overweight adults (mean+/-SD, age 35+/-5y; BMI 27.5+/-1.5 kg/m(2)). Total energy expenditure (TEE), resting metabolic rate (RMR), fat and fat free mass (FFM), were measured at 3, 6 and 12 months. Changes in TEE, but not changes in RMR, were greater than accounted for by the loss of FFM and fat mass (P=0.001-0.013) suggesting an adaptive response to long-term CR. There was no significant effect of diet group on change in RMR or TEE. However, in subjects who lost >5% body weight (n=26), the LG diet group had a higher percentage of weight loss as fat than the HG group (p<0.05), a finding that may have implications for dietary recommendations during weight reduction.

Use of cereal fiber to facilitate adherence to a human caloric restriction program

Background and aims: Caloric restriction (CR) attenuates biological aging in animal models but there is little information on the feasibility and efficacy of CR regimens in humans. We examined the effects of consuming an insoluble cereal fiber supplement on ability to sustain CR over 1 year in healthy overweight adults. Methods: In 34 healthy overweight women and men (BMI 25–30 kg/m2, age 20–42 yr), a 30% CR regimen meeting national recommendations for dietary fiber was provided for 24 weeks, and for an additional 24 weeks subjects were counseled to prepare the same regimen at home. During 5–10 weeks of CR, subjects were randomized to consume an extra 20 g/day of dietary fiber from a high fiber cereal (+F) or to not consume additional fiber (−F). After this time, all subjects were encouraged to consume the extra fiber. Outcomes included adherence to the provided and self-prepared CR regimens (energy intake determined using doubly labeled water), changes in body weight, and self-reported satisfaction with the amount of consumed food. Results: During 5–10 weeks of CR when all food was provided, both +F and −F groups were highly adherent to the CR regimen and there was no significant difference between groups in energy intake (p=0.51), weight change (p=0.96), or satisfaction with amount of provided food (p=0.08). During self-prepared CR from 25 to 48 weeks, mean adherence was lower than during the food-provided phase and there was a significant association between fiber intake and % CR (r=0.69, p<0.001), decreased BMI (r=− 0.38, p=0.04) and satisfaction with the amount of consumed food (r=0.59, p=0.002). Conclusions: A high fiber cereal intake may facilitate CR in humans self-selecting their own food; longer-term intervention studies are needed to confirm these findings.

Effect of glycemic load on eating behavior self-efficacy during weight loss.

High eating behavior self-efficacy may contribute to successful weight loss. Diet interventions that maximize eating behavior self-efficacy may therefore improve weight loss outcomes. However, data on the effect of diet composition on eating behavior self-efficacy are sparse. To determine the effects of dietary glycemic load (GL) on eating behavior self-efficacy during weight loss, body weight and eating behavior self-efficacy were measured every six months in overweight adults participating in a 12-mo randomized trial testing energy-restricted diets differing in GL. All food was provided during the first six months and self-selected thereafter. Total mean weight loss did not differ between groups, and GL-level had no significant effect on eating behavior self-efficacy. In the combined cohort, individuals losing the most weight reported improvements in eating behavior self-efficacy, whereas those achieving less weight loss reported decrements in eating behavior self-efficacy. Decrements in eating behavior self-efficacy were associated with subsequent weight regain when diets were self-selected. While GL does not appear to influence eating behavior self-efficacy, lesser amounts of weight loss on provided-food energy restricted diets may deter successful maintenance of weight loss by attenuating improvements in eating behavior self-efficacy.