Is weight loss the optimal target for obesity-related cardiovascular disease risk reduction?

Financial incentives for exercise adherence in adults: systematic review and meta-analysis

CONTEXT

Less than 5% of U.S. adults accumulate the required dose of exercise to maintain health. Behavioral economics has stimulated renewed interest in economic-based, population-level health interventions to address this issue. Despite widespread implementation of financial incentive-based public health and workplace wellness policies, the effects of financial incentives on exercise initiation and maintenance in adults remain unclear.

EVIDENCE ACQUISITION

A systematic search of 15 electronic databases for RCTs reporting the impact of financial incentives on exercise-related behaviors and outcomes was conducted in June 2012. A meta-analysis of exercise session attendance among included studies was conducted in April 2013. A qualitative analysis was conducted in February 2013 and structured along eight features of financial incentive design.

EVIDENCE SYNTHESIS

Eleven studies were included (N=1453; ages 18-85 years and 50% female). Pooled results favored the incentive condition (z=3.81, p<0.0001). Incentives also exhibited significant, positive effects on exercise in eight of the 11 included studies. One study determined that incentives can sustain exercise for longer periods (>1 year), and two studies found exercise adherence persisted after the incentive was withdrawn. Promising incentive design feature attributes were noted. Assured, or "sure thing," incentives and objective behavioral assessment in particular appear to moderate incentive effectiveness. Previously sedentary adults responded favorably to incentives 100% of the time (n=4).

CONCLUSIONS

The effect estimate from the meta-analysis suggests that financial incentives increase exercise session attendance for interventions up to 6 months in duration. Similarly, a simple count of positive (n=8) and null (n=3) effect studies suggests that financial incentives can increase exercise adherence in adults in the short term (<6 months).

Clinically significant improved fitness and weight loss among overweight persons with serious mental illness

OBJECTIVE

The objective of this study was to evaluate the effectiveness of a fitness health mentor program (In SHAPE) in improving physical fitness and weight loss among overweight and obese adults with serious mental illness.

METHODS

A randomized controlled trial was conducted with 133 persons with serious mental illness and a body mass index (BMI) >25 who were assigned either to the In SHAPE program (one year of weekly sessions with a fitness trainer plus a fitness club membership) or to one year of fitness club membership and education. Assessments were conducted at baseline and three, six, nine, and 12 months later.

RESULTS

Participants had a mean baseline weight of 231.8±54.8 pounds and a mean BMI of 37.6±8.2. At 12-month follow-up, In SHAPE (N=67) compared with fitness club membership and education (N=66) was associated with three times greater fitness club attendance, twice as much participation in physical exercise, greater engagement in vigorous physical activity, and improvement in diet. Twice the proportion of participants (40% versus 20%) achieved clinically significant improvement in cardiorespiratory fitness (>50 m on the six-minute walk test). Weight loss and BMI did not differ between groups. Among In SHAPE participants, 49% achieved either clinically significant increased fitness or weight loss (5% or greater), and 24% achieved both clinically significant improved fitness and weight loss.

CONCLUSIONS

The In SHAPE program achieved clinically significant reduction in cardiovascular risk for almost one-half of participants at 12 months. Although the intervention showed promise in improving fitness, optimizing weight loss may require additional intensive, multicomponent dietary interventions.

Effects of an intensive short-term diet and exercise intervention: comparison between normal-weight and obese children

Lifestyle intervention programs currently emphasize weight loss secondary to obesity as the primary determinant of phenotypic changes. We examined whether the effects of a short-term lifestyle intervention program differ in normal-weight versus overweight/obese children. Nineteen overweight/obese (O; BMI = 33.6 ± 1.9 kg/m(2)) and 14 normal-weight (N; BMI = 19.9 ± 1.5 kg/m(2)) children participated in a 2-wk program consisting of an ad libitum high-fiber, low-fat diet and daily exercise (2-2.5 h). Fasting serum samples were taken pre- and postintervention for determination of lipids, glucose homeostasis, inflammatory cytokines, and adipokines. Only the O group lost weight (3.9%) but remained overweight/obese (32.3 ± 1.9 kg/m(2)). Both groups exhibited significant intervention-induced decreases (P < 0.05) in serum insulin (N: 52.5% vs. O: 28.1%; between groups, P = 0.38), homeostatic model assessment for insulin resistance (N: 53.1% vs. O: 28.4%, P = 0.43), leptin (N: 69.3% vs. O: 44.1%, P = 0.10), amylin (N: 28.7% vs. O: 26.1%, P = 0.80), resistin (N: 40.0% vs. O: 35.1%, P = 0.99), plasminogen activator-inhibitor-1 (N: 30.8% vs. O: 25.6%, P = 0.59), IL-6 (N: 58.8% vs. O: 48.5%, P = 0.78), IL-8 (N: 46.0% vs. O: 42.2%, P = 0.49), and TNFα (N: 45.8% vs. O: 40.8%, P = 0.99). No associations between indices of weight change and phenotypic changes were noted. A short-term, intensive lifestyle modification program is effective in ameliorating metabolic risk factors in N and O children. These results suggest that obesity per se was not the primary driver of the phenotypes noted and that dietary intake and physical inactivity induce the phenotypic abnormalities. These data may have implications for the weight loss-independent management of cardiometabolic risk in pediatric populations.

Interventions for lifestyle changes to promote weight reduction, a randomized controlled trial in primary health care

Background

Overweight and obesity are growing public health problems in high income countries and is now growing at a dramatic pace in low and middle income countries, particularly in urban settings. The aim of this trial was to examine the effects of a weight reduction program in adults and to determine whether or not a more extensive intervention was superior to ordinary care.

Methods

Patients seeking advice for overweight/obesity or illness related to overweight/obesity at eight primary health care centers in Sweden were randomized either to intervention or control care groups with both groups given dietary advice and individualized information on increased regular physical activity. In the intervention group advice was more extensive and follow-up more frequent than in the control group during the study period of two years. Main outcome measure was reduction in body weight of five percent or more from study start.

Results

From October 2004 to April 2006, 133 patients, 67 in the intervention group and 66 in the control group, were randomized over a period of 18 months. Target weight was achieved at 12 months by 26.7% of the patients in the intervention group compared with 18.4% in the control group (p = 0.335). There was an average absolute weight loss of 2.5 kg in the intervention group and 0.8 kg in the control group at 12 months as compared with the weight at study entry. There were no significant differences between the groups in quality of life, blood glucose and lipids. At 24 months target weight was achieved in 21.9% versus 15.6%, with an average weight reduction of 1.9 kg and 1.2 kg in the two groups, respectively.

Conclusions

Promotion of a diet with limited energy intake, appropriate composition of food and increased physical activity had limited effects on body weight in a Swedish primary care setting. More extensive advice and more frequent visits made no significant difference to the outcome.

Trial registration

ClinicalTrial.gov: NCT01606917

Pathophysiology of human visceral obesity: an update

Excess intra-abdominal adipose tissue accumulation, often termed visceral obesity, is part of a phenotype including dysfunctional subcutaneous adipose tissue expansion and ectopic triglyceride storage closely related to clustering cardiometabolic risk factors. Hypertriglyceridemia; increased free fatty acid availability; adipose tissue release of proinflammatory cytokines; liver insulin resistance and inflammation; increased liver VLDL synthesis and secretion; reduced clearance of triglyceride-rich lipoproteins; presence of small, dense LDL particles; and reduced HDL cholesterol levels are among the many metabolic alterations closely related to this condition. Age, gender, genetics, and ethnicity are broad etiological factors contributing to variation in visceral adipose tissue accumulation. Specific mechanisms responsible for proportionally increased visceral fat storage when facing positive energy balance and weight gain may involve sex hormones, local cortisol production in abdominal adipose tissues, endocannabinoids, growth hormone, and dietary fructose. Physiological characteristics of abdominal adipose tissues such as adipocyte size and number, lipolytic responsiveness, lipid storage capacity, and inflammatory cytokine production are significant correlates and even possible determinants of the increased cardiometabolic risk associated with visceral obesity. Thiazolidinediones, estrogen replacement in postmenopausal women, and testosterone replacement in androgen-deficient men have been shown to favorably modulate body fat distribution and cardiometabolic risk to various degrees. However, some of these therapies must now be considered in the context of their serious side effects. Lifestyle interventions leading to weight loss generally induce preferential mobilization of visceral fat. In clinical practice, measuring waist circumference in addition to the body mass index could be helpful for the identification and management of a subgroup of overweight or obese patients at high cardiometabolic risk.

'Sarcobesity': a metabolic conundrum

Two independent but inter-related conditions that have a growing impact on healthy life expectancy and health care costs in developed nations are an age-related loss of muscle mass (i.e., sarcopenia) and obesity. Sarcopenia is commonly exacerbated in overweight and obese individuals. Progression towards obesity promotes an increase in fat mass and a concomitant decrease in muscle mass, producing an unfavourable ratio of fat to muscle. The coexistence of diminished muscle mass and increased fat mass (so-called 'sarcobesity') is ultimately manifested by impaired mobility and/or development of life-style-related diseases. Accordingly, the critical health issue for a large proportion of adults in developed nations is how to lose fat mass while preserving muscle mass. Lifestyle interventions to prevent or treat sarcobesity include energy-restricted diets and exercise. The optimal energy deficit to reduce body mass is controversial. While energy restriction in isolation is an effective short-term strategy for rapid and substantial weight loss, it results in a reduction of both fat and muscle mass and therefore ultimately predisposes one to an unfavourable body composition. Aerobic exercise promotes beneficial changes in whole-body metabolism and reduces fat mass, while resistance exercise preserves lean (muscle) mass. Current evidence strongly supports the inclusion of resistance and aerobic exercise to complement mild energy-restricted high-protein diets for healthy weight loss as a primary intervention for sarcobesity.

The downside of weight loss: realistic intervention in body-weight trajectory

OBJECTIVE

To explore the reasons why long-term weight loss is seldom achieved and to evaluate the consequences of various weight trajectories, including stability, loss, and gain.

QUALITY OF EVIDENCE

Studies evaluating population weight metrics were mainly observational. Level I evidence was available to evaluate the influence of weight interventions on mortality and quality of life.

MAIN MESSAGE

Sustained weight loss is achieved by a small percentage of those intending to lose weight. Mortality is lowest in the high-normal and overweight range. The safest body-size trajectory is stable weight with optimization of physical and metabolic fitness. With weight loss there is evidence for lower mortality in those with obesity-related comorbidities. There is also evidence for improved health-related quality of life in obese individuals who lose weight. Weight loss in the healthy obese, however, is associated with increased mortality.

CONCLUSION

Weight loss is advisable only for those with obesity-related comorbidities. Healthy obese people wishing to lose weight should be informed that there might be associated risks. A strategy that leads to a stable body mass index with optimized physical and metabolic fitness at any size is the safest weight intervention option.

Innovative program to increase physical activity following an acute coronary syndrome: randomized controlled trial

OBJECTIVE

To evaluate the impact of a socio-cognitive intervention associated with a pedometer-based program on physical activity, cardiovascular risk factors and self-efficacy expectation during one year following an acute coronary syndrome.

METHODS

Sixty-five subjects were randomized during hospitalization in an experimental or a usual care group. Average steps/day was measured every 3 months until one year following discharge. Other dependent variables were measured at baseline, 6 and 12 months follow-up.

RESULTS

There were 32 patients in the experimental group and 33 patients in the usual care group. Group characteristics were comparable. At baseline, averages steps/day were similar between groups (5845±3246 vs. 6097±3055 steps/day; p=0.812). At 3-month follow-up, both groups increased their averages steps/day (p<0.05). This increase was higher in the experimental group (3388±844 vs. 1934±889 steps/day; p<0.001). At 12-month, interaction effects (group×time) in physical activity and waist circumference were different between groups (p<0.05), whereas self-efficacy expectation increased in both groups similarly (p<0.05).

CONCLUSION

The intervention is useful to improve average steps/day and waist circumference during the first year following an acute coronary syndrome.

PRACTICE IMPLICATIONS

This study supports development of the home-based cardiac rehabilitation program using socio-cognitive intervention associated with a pedometer after an acute coronary syndrome.

The obesity paradox and weight loss

BACKGROUND

An "obesity paradox," in which overweight and obese individuals with established cardiovascular disease have a better prognosis than normal weight subjects, has been reported in a number of clinical cohorts, but little is known about the effects of weight loss on the obesity paradox and its association with health outcomes.

METHODS

Weight was determined in 3834 men at the time of a clinically referred exercise test and again during a clinical evaluation a mean of 7 years later. The associations among weight changes, baseline fitness, and other risk markers with cardiovascular and all-cause mortality were determined by Cox proportional hazards analysis.

RESULTS

During the follow-up period, 314 subjects died (72 of cardiovascular causes). In a multivariate analysis (including baseline weight, weight change, exercise capacity, and cardiovascular disease), weight gain was associated with lower mortality and weight loss was associated with higher mortality (4% higher per pound lost per year, P<.001) compared with stable weight. For all-cause mortality, the relative risks for the no change, weight gain, and weight loss groups were 1.0 (referent), 0.64 (95% confidence interval, 0.50-0.83), and 1.49 (95% confidence interval, 1.17-1.89), respectively (P<.001). Those who died and exhibited weight loss had a significantly higher prevalence of deaths due to cancer and cardiovascular causes.

CONCLUSION

Weight loss was related to higher mortality and weight gain was related to lower mortality when compared with stable weight. The obesity paradox in our sample is explained in part by a combination of non-volitional weight loss related to occult disease and a protective effect of weight gain.

Body mass index and health status in the Bypass Angioplasty Revascularization Investigation 2 Diabetes Trial (BARI 2D)

BACKGROUND

The longitudinal association between obesity, weight variability, and health status outcomes is important for patients with coronary disease and diabetes.

METHODS

The BARI 2D was a multicenter randomized clinical trial designed to evaluate treatment strategies for patients with both documented stable ischemic heart disease and type 2 diabetes. We examined BARI 2D participants for 4 years to study how body mass index (BMI) was associated with health status outcomes. Health status was evaluated by the Duke Activity Status Index (DASI), RAND Energy/fatigue, Health Distress, and Self-rated Health. Body mass index was measured quarterly throughout follow-up years, and health status was assessed at each annual follow-up visit. Variation in BMI measures was separated into between-person and within-person change in longitudinal analysis.

RESULTS

Higher mean BMI during follow-up years (the between-person BMI) was associated with poorer health status outcomes. Decreasing BMI (the within-person BMI change) was associated with better Self-rated health. The relationships between BMI variability and DASI or Energy appeared to be curvilinear and differed by baseline obesity status. Decreasing BMI was associated with better outcomes if patients were obese at baseline but was associated with poorer DASI and Energy outcomes if patients were nonobese at baseline.

CONCLUSIONS

For patients with stable ischemic heart disease and diabetes, weight gain was associated with poorer health status outcomes, independent of obesity-related comorbidities. Weight reduction is associated with better functional capacity and perceived energy for obese patients but not for nonobese patients at baseline.

The effect of increasing consumption of pulses and wholegrains in obese people: a randomized controlled trial

BACKGROUND

Wholegrain intake is inversely related to weight gain over time, but little information is available on the role of pulses in weight control.

OBJECTIVE

To compare weight loss, metabolic outcomes, and nutrient intakes in obese people assigned to a diet rich in pulses and wholegrains or a control diet.

METHODS

Randomized controlled study of 18 months with 113 volunteers (body mass index [BMI] ≥ 28 kg/m(2)). Diets were based on guidelines published by the National Heart Foundation of New Zealand. The intervention group was advised to consume 2 serves of pulses and 4 serves of wholegrain foods per day as substitutions for more refined carbohydrates.

RESULTS

Fiber intakes were higher, intakes of several vitamins and minerals were better maintained, and dietary glycemic index was lower in the intervention compared with the control group. Mean (standard error [SE]) weight loss at 6 months was 6.0 (0.7) kg and 6.3 (0.6) kg in the control and intervention groups, respectively, and was not different between groups (p > 0.05). Blood pressure, triglycerides, and glycemic load were lowered in both groups compared with baseline. Waist circumference was decreased at 18 months in the intervention compared with the control group (-2.8 cm; 95% confidence interval [CI]: -0.4, -5.1).

CONCLUSIONS

Incorporation of pulses and wholegrain foods into a weight loss program resulted in a greater reduction in waist circumference compared with the group consuming a control diet, although no difference in weight loss was noted between groups. Retention of several nutrients was better with the pulse and wholegrain diet.

Association of retinol-binding protein-4 (RBP4) with lipid parameters in obese women

BACKGROUND

Although the adipokine retinol-binding protein-4 (RBP4) has been implicated in the development of obesity-related insulin resistance, its role in human obesity is still unclear. Our objectives were to find out the effect on RBP4 systemic levels of a weight loss induced by gastric bypass surgery and to analyze RBP4 relationships with insulin resistance, parameters of body composition, lipid metabolism, and inflammation.

METHODS

Sixty-three obese women were analyzed before and 12 months after surgery of systemic concentrations of RBP4, fasting glucose, insulin, lipid profile molecules, and inflammation-related proteins (C-reactive protein, tumor necrosis factor-alpha receptors 1 and 2, interleukin-18, and adiponectin), and waist and hip circumference measurements, body mass index calculation, and insulin resistance index by homeostasis model assessment were also made.

RESULTS

We found that RBP4 levels were lower after weight reduction by gastric bypass surgery (p < 0.0001). We found RBP4 associated with triglycerides before (beta = 0.37, p = 0.02) and after surgery (beta = 0.59, p < 0.0001) and negatively with weight loss after surgery (beta = -0.37, p = 0.003). When expressed as a percentage of change, the decrease of RBP4 was related to the reduction in the levels of triglycerides and with the increase in HDL-cholesterol (beta = 0.73, p = 0.02 and beta = 0.62, p = 0.04, respectively). Others parameters analyzed, including inflammatory markers, were not related to RBP4.

CONCLUSIONS

This study shows that, in obese women and after a substantial weight loss due to bariatric surgery, RBP4 was related to weight status and lipid parameters rather than to insulin sensitivity or inflammatory markers.

The influence of physical activity on appetite control: an experimental system to understand the relationship between exercise-induced energy expenditure and energy intake

Investigations of the impact of physical activity on appetite control have the potential to throw light on the understanding of energy balance and therefore, upon body weight regulation and the development of obesity. Given the complexity of the landscape influencing weight regulation, research strategies should reflect this complexity. We have developed a research approach based on the concept of the psychobiological system (multi-level measurement and analysis) and an experimental platform that respects the operations of an adaptive regulating biological system. It is important that both sides of the energy balance equation (activity and diet) receive similar detailed levels of analysis. The experimental platform uses realistic and fully supervised levels of physical activity, medium-term (not acute) interventions, measurement of body composition, energy metabolism (indirect calorimetry), satiety physiology (gut peptides), homeostatic and hedonic processes of appetite control, non-exercise activity, obese adult participants and both genders. This research approach has shown that the impact of physical activity on appetite control is characterised by large individual differences. Changes in body composition, waist circumference and health benefits are more meaningful than changes in weight. Further, we are realising that the acute effects do not predict what will happen in the longer term. The psychobiological systems approach offers a strategy for simultaneously investigating biological and behavioural processes relevant to understanding obese people and how obesity can be managed. This experimental platform provides opportunities for industry to examine the impact of foods under scientifically controlled conditions relevant to the real world.

Randomized controlled pilot trial of yoga in overweight and obese breast cancer survivors: effects on quality of life and anthropometric measures

PURPOSE

To obtain estimates of time to recruit the study sample, retention, facility-based class attendance and home practice for a study of yoga in breast cancer survivors, and its efficacy on fatigue, quality of life (QOL), and weight change.

METHODS

Sixty-three post-treatment stages 0-III borderline overweight and obese (body mass index ≥ 24 kg/m(2)) breast cancer survivors were randomly assigned to a 6-month, facility- and home-based viniyoga intervention (n = 32) or a waitlist control group (n = 31). The yoga goal was five practices per week. Primary outcome measures were changes in QOL, fatigue, and weight from baseline to 6 months. Secondary outcomes included changes in waist and hip circumference.

RESULTS

It took 12 months to complete recruitment. Participants attended a mean of 19.6 classes and practiced at home a mean of 55.8 times during the 6-month period. At follow-up, 90% of participants completed questionnaires and 87% completed anthropometric measurements. QOL and fatigue improved to a greater extent among women in the yoga group relative to women in the control group, although no differences were statistically significant. Waist circumference decreased 3.1 cm (95% CI, -5.7 and -0.4) more among women in the yoga compared with the control group, with no difference in weight change.

CONCLUSIONS

This study provides important information regarding recruitment, retention, and practice levels achieved during a 6-month, intensive yoga intervention in overweight and obese breast cancer survivors. Yoga may help decrease waist circumference and improve quality of life; future studies are needed to confirm these results.

Physical activity plays an important role in body weight regulation

Emerging literature highlights the need to incorporate physical activity into every strategy intended to prevent weight gain as well as to maintain weight loss over time. Furthermore, physical activity should be part of any plan to lose weight. The stimulus of exercise provides valuable metabolic adaptations that improve energy and macronutrient balance regulation. A tight coupling between energy intake and energy expenditure has been documented at high levels of physical exercise, suggesting that exercise may improve appetite control. The regular practice of physical activity has also been reported to reduce the risk of stress-induced weight gain. A more personalized approach is recommended when planning exercise programs in a clinical weight loss setting in order to limit the compensatory changes associated to exercise-induced weight loss. With modern environment promoting overeating and sedentary behavior, there is an urgent need for a concerted action including legislative measures to promote healthy active living in order to curb the current epidemic of chronic diseases.

Cardiorespiratory fitness and metabolic risk factors in obesity

PURPOSE OF REVIEW

An increase in cardiorespiratory fitness (CRF) through exercise training appears to partly ameliorate the health hazards of obesity and a number of mechanisms might explain the potential benefits. We review recent evidence about the relationships between CRF, exercise training and metabolic risk factors in obesity.

RECENT FINDINGS

Epidemiological data have shown that the anti-inflammatory effects of exercise could be an important mechanism in explaining cardio-protective effects of physical activity. Emerging evidence suggests that exercise training reduces markers of inflammation and improves glucose control in obesity, independent of weight loss. Novel mechanisms appear to involve exercise-induced changes in CD14+CD16+ cell populations, expression of toll-like receptors, and key changes in the metabolic regulation of visceral white adipose tissue. Other promising recent research has focused on exercise-induced signalling pathways governing glucose metabolism, such as insulin receptor substrate and Akt substrate. Using novel imaging techniques, studies have demonstrated exercise-induced improvements in lipoprotein subfraction particle size, and reduction in visceral adipose tissue and liver fat, independent of weight loss. These effects appear to be mostly restricted to interventions consisting of relatively high doses of exercise or exercise combined with calorie restriction, although further work is required to elucidate the dose-response relationships.

SUMMARY

Physical activity and the pursuit of physical fitness are important in the treatment of obesity because exercise training can improve a number of metabolic risk factors independent of weight loss. Thus exercise can provide important health benefits irrespective of weight loss in obese and overweight individuals.