Kathleen J. Melanson

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.

Changes in eating behaviour and meal pattern following Roux-en-Y gastric bypass

Background:Little is known about eating behaviour and meal pattern subsequent to Roux-en-Y gastric bypass (RYGB), knowledge important for the nutritional care process. The objective of the study was to obtain basic information of how meal size, eating rate, meal frequency and eating behaviour change upon the RYGB surgery.Materials and methods:Voluntary chosen meal size and eating rate were measured in a longitudinal, within subject, cohort study of 43 patients, 31 women and 12 men, age 42.6 (s.d. 9.7) years, body mass index (BMI) 44.5 (4.9) kg m−2. Thirty-one non-obese subjects, 37.8 (13.6) years, BMI 23.7 (2.7) kg m−2 served as a reference group. All subjects completed a meal pattern questionnaire and the Three-Factor Eating Questionnaire (TFEQ-R21).Results:Six weeks postoperatively meal size was 42% of the preoperative meal size, (P<0.001). After 1 and 2 years, meal size increased but was still lower than preoperative size 57% (P<0.001) and 66% (P<0.001), respectively. Mean meal duration was constant before and after surgery. Mean eating rate measured as amount consumed food per minute was 45% of preoperative eating rate 6 weeks postoperatively (P<0.001). After 1 and 2 years, eating rate increased to 65% (P<0.001) and 72% (P<0.001), respectively, of preoperative rate. Number of meals per day increased from 4.9 (95% confidence interval, 4.4,5.4) preoperatively to 6 weeks: 5.2 (4.9,5.6), (not significant), 1 year 5.8 (5.5,6.1), (P=0.003), and 2 years 5.4 (5.1,5.7), (not significant). Emotional and uncontrolled eating were significantly decreased postoperatively, (both P<0.001 at all-time points), while cognitive restraint was only transiently increased 6 weeks postoperatively (P=0.011).Conclusions:Subsequent to RYGB, patients display markedly changed eating behaviour and meal patterns, which may lead to sustained weight loss.

Obesity and cardiovascular disease risk: research update.

The obesity epidemic has reached unprecedented proportions in Western society. Evidence continues to accumulate that obesity is associated with significant morbidity and mortality and in particular that it is an independent risk factor for cardiovascular disease (CVD). The association of obesity with CVD and its risk factors, including hypertension, dyslipidemia, glucose intolerance, and impaired hemostasis is becoming more clearly understood. An increasing body of data indicates that risk factors tend to cluster in obese individuals and may act synergistically to increase these people’s risk for CVD. Individuals with disproportionate visceral adiposity are at significantly greater risk for CVD. Adult weight gain also underlies the development of many risk factors and augments the risk of CVD. Physicians can play a vital and active role in the prevention and treatment of obesity and overweight and thereby reduce patients’ CVD risk.

High-fructose corn syrup, energy intake, and appetite regulation

High-fructose corn syrup (HFCS) has been implicated in excess weight gain through mechanisms seen in some acute feeding studies and by virtue of its abundance in the food supply during years of increasing obesity. Compared with pure glucose, fructose is thought to be associated with insufficient secretion of insulin and leptin and suppression of ghrelin. However, when HFCS is compared with sucrose, the more commonly consumed sweetener, such differences are not apparent, and appetite and energy intake do not differ in the short-term. Longer-term studies on connections between HFCS, potential mechanisms, and body weight have not been conducted. The main objective of this review was to examine collective data on associations between consumption of HFCS and energy balance, with particular focus on energy intake and its regulation.

The Effect of High-Fructose Corn Syrup Consumption on Triglycerides and Uric Acid

Rates of overweight and obesity have been on a steady rise for decades, and the problems society faces from this and associated metabolic diseases are many. As a result, the need to understand the contributing factors is great. A very compelling case can be made that excess sugar consumption has played a significant role. In addition, fructose, as a component of the vast majority of caloric sweeteners, is seen to be particularly insidious. Evidence shows that fructose bypasses many of the bodys satiating signals, thus potentially promoting overconsumption of energy, weight gain, and the development on insulin resistance. It has also been shown to increase uric acid levels, which in turn promotes many of the abnormalities seen in the metabolic syndrome including hypertriglyceridemia. However, the main source of fructose in the diet is high-fructose corn syrup (HFCS), an artificially manufactured disaccharide that is only 55% fructose. This review highlights the fact that limited data are available about the metabolic effects of HFCS compared with other caloric sweeteners. The data suggest that HFCS yields similar metabolic responses to other caloric sweeteners such as sucrose.

The effect of physical activity on weight loss is mediated by eating self-regulation

OBJECTIVE This study tested whether different forms of physical activity (PA) were associated with eating self-regulation during weight control, and if changes in eating behavior mediated the relationship between PA and weight loss, in overweight/obese women. METHODS 239 women (37.6+/-7.0 years; 31.3+/-4.1kg/m(2)) participated. The intervention group received a 12-month group behavioral treatment designed to increase autonomy and self-regulation for weight control. Controls received a health education program. Assessments included body weight, structured and lifestyle exercise/PA, and eating self-regulation. RESULTS Moderate+vigorous and lifestyle PA were associated with 12-month change in most eating variables (p<0.05) and with body weight change (p<0.01). Mediation analysis showed that flexible cognitive restraint and emotional eating fully mediated the relation between lifestyle PA and weight change (effect ratio: 0.63). About 34% of the effect of moderate+vigorous PA on weight change was explained by these same mediators (partial mediation). CONCLUSION Exercise and PA may positively influence weight control through eating self-regulation. Flexible dietary control and reduced emotional overeating are mechanisms by which an active lifestyle can contribute to long-term weight management. PRACTICE IMPLICATIONS Regular exercise and PA can contribute to improved eating behaviors during weight management. This could represent an important incentive for people seeking weight control.

Weight loss and total lipid profile changes in overweight women consuming beef or chicken as the primary protein source

OBJECTIVE Conflicting recommendations are prevalent regarding the appropriateness of red meat versus white meat consumption for individuals aiming to reduce body weight and cardiovascular disease risk. METHODS We examined changes in body weight and lipid profiles in a 12-wk, randomized, controlled trial, in which overweight women followed a hypocaloric diet with lean beef or chicken as the primary protein source, while participating in a fitness walking program. Sedentary non-smoking females (n = 61), age 43.4 +/- 7.8 years, with body mass indexes of 32.1 +/- 3.4 kg/m(2) (means +/- standard deviation), followed calculated-deficit diets (-500 kcal daily) and were randomly assigned to the beef-consumption or chicken-consumption dietary group, while following a fitness walking program. Body weight, body composition (by hydrodensitometry), and blood lipid profiles were measured at baseline and 12 wk. RESULTS Weight loss was significant within (P < 0.05) but similar between (P > 0.05) the beef-consumption (5.6 +/- 0.6 kg, mean +/- standard error) and the chicken-consumption (6.0 +/- 0.5 kg) groups. Both groups showed significant reductions in body fat percentage (P < 0.05) and total (P < 0.05) and low-density lipoprotein (P < 0.05) cholesterol, with no significant differences between groups. High-density lipoprotein cholesterol did not change significantly in either group. CONCLUSIONS These findings demonstrated that weight loss and improved lipid profile can be accomplished through diet and exercise, whether the dietary protein source is lean beef or chicken.

Decreased energy density and changes in food selection following Roux-en-Y gastric bypass.

Background/Objectives:The main objective was to test the hypothesis that dietary energy density (DED) decreases after Roux-en-Y gastric bypass (gastric bypass).Subjects/Methods:A total of 43 patients (31 women and 12 men) aged 43 (s.d. 10) years, with body mass index (BMI) 44.3 kg/m2 (4.9), were assessed preoperatively at 6 weeks and 1 and 2 years after gastric bypass. Self-reported energy intake (EI), food weight (FW) and food choice were assessed using a dietary questionnaire. DED was calculated by dividing EI by FW (kcal/g). Number of dropouts was 4 of 203 visits.Results:Percent weight loss (%WL) was 13.5% at 6 weeks, 30.7% at 1 year and 31.8% at 2 years post surgery (P<0.001 for all). EI decreased from 2990 to 1774, 2131 and 2425 kcal after 6 weeks and 1 and 2 years postoperatively, respectively (P<0.001 at all time points). FW changed from 2844 to 1870 g/day at 6 weeks (P<0.001) and 2416 g/day after 1 year (P<0.05), but was not significantly different from baseline 2 years postoperatively (2602 g/day, P=0.105). DED decreased from 1.07 to 0.78 kcal/g at 6 weeks (P<0.001) and 0.90 kcal/g (P<0.001) and 0.96 kcal/g (P=0.001) after 1 and 2 years, respectively. All statistical comparisons were made from baseline. There was no correlation between changes in DED and %WL, neither after 1 year (r=−0.215; P=0.183) nor after 2 years (r=−0.046; P=0.775) post surgery.Conclusions:Besides substantial reduction in EI and large variation in FW, patients reported decreased DED over 2 years following gastric bypass. Despite lack of association between the reduction in DED and percentage weight loss, changes in food choice were overall nutritionally beneficial.

Body composition, dietary composition, and components of metabolic syndrome in overweight and obese adults after a 12-week trial on dietary treatments focused on portion control, energy density, or glycemic index

BackgroundGiven the rise in obesity and associated chronic diseases, it is critical to determine optimal weight management approaches that will also improve dietary composition and chronic disease risk factors. Few studies have examined all these weight, diet, and disease risk variables in subjects participating in recommended multi-disciplinary weight loss programs using different dietary strategies.MethodsThis study compared effects of three dietary approaches to weight loss on body composition, dietary composition and risk factors for metabolic syndrome (MetS). In a 12-week trial, sedentary but otherwise healthy overweight and obese adults (19 M & 138 F; 38.7 ± 6.7 y; BMI 31.8 ± 2.2) who were attending weekly group sessions for weight loss followed either portion control, low energy density, or low glycemic index diet plans. At baseline and 12 weeks, measures included anthropometrics, body composition, 3-day food diaries, blood pressure, total lipid profile, HOMA, C-reactive protein, and fasting blood glucose and insulin. Data were analyzed by repeated measures analysis of variance.ResultsAll groups significantly reduced body weight and showed significant improvements in body composition (p < 0.001), and components of metabolic syndrome (p < 0.027 to 0.002), although HDL decreased (p < 0.001). Dietary energy, %fat and %saturated fat decreased while protein intake increased significantly (p < 0.001). There were no significant differences among the three groups in any variable related to body composition, dietary composition, or MetS components.ConclusionDifferent dietary approaches based on portion control, low energy density, or low glycemic index produced similar, significant short-term improvements in body composition, diet compositin, and MetS components in overweight and obese adults undergoing weekly weight loss meetings. This may allow for flexibility in options for dietary counseling based on patient preference.

The effects of four hypocaloric diets containing different levels of sucrose or high fructose corn syrup on weight loss and related parameters

BackgroundThe replacement of sucrose with HFCS in food products has been suggested as playing a role in the development of obesity as a public health issue. The objective of this study was to examine the effects of four equally hypocaloric diets containing different levels of sucrose or high fructose corn syrup (HFCS).MethodsThis was a randomized, prospective, double blind trial, with overweight/obese participants measured for body composition and blood chemistry before and after the completion of 12 weeks following a hypocaloric diet. The average caloric deficit achieved on the hypocaloric diets was 309 kcal.ResultsReductions were observed in all measures of adiposity including body mass, BMI,% body fat, waist circumference and fat mass for all four hypocaloric groups, as well as reductions in the exercise only group for body mass, BMI and waist circumference.ConclusionsSimilar decreases in weight and indices of adiposity are observed when overweight or obese individuals are fed hypocaloric diets containing levels of sucrose or high fructose corn syrup typically consumed by adults in the United States.