Background: Exercise intensity may affect the selective loss of abdominal adipose tissue.
Objective: This study showed whether aerobic exercise intensity affects the loss of abdominal fat and improvement in cardiovascular disease risk factors under conditions of equal energy deficit in women with abdominal obesity.
Design: This was a randomized trial in 112 overweight and obese [body mass index (in kg/m2): 25–40; waist circumference .88 cm], postmenopausal women assigned to one of three 20-wk interventions of equal energy deficit: calorie restriction (CR only), CR plus moderate-intensity aerobic exercise (CR 1 moderate-intensity), or CR plus vigorous-intensity exercise (CR 1 vigorous-intensity). The diet was a controlled program of underfeeding during which meals were provided at individual calorie levels (’400 kcal/d). Exercise (3 d/wk) involved treadmill walking at an intensity of 45–50% (moderate-intensity) or 70–75% (vigorous-intensity) of heart rate reserve. The primary outcome was abdominal visceral fat volume.
Results: Average weight loss for the 95 women who completed the study was 12.1 kg (64.5 kg) and was not significantly different across groups. Maximal oxygen uptake ( _V O2max) increased more in the CR 1 vigorous-intensity group than in either of the other groups (P , 0.05). The CR-only group lost relatively more lean mass than did either exercise group (P , 0.05). All groups showed similar decreases in abdominal visceral fat (’25%; P , 0.001 for all). However, changes in visceral fat were inversely related to increases in _V O2max (P , 0.01). Changes in lipids, fasting glucose or insulin, and 2-h glucose and insulin areas during the oral-glucosetolerance test were similar across treatment groups.
Conclusion: With a similar amount of total weight loss, lean mass is preserved, but there is not a preferential loss of abdominal fat when either moderate- or vigorous-intensity aerobic exercise is performed during caloric restriction.
Effect of exercise intensity on abdominal fat loss during calorie restriction in overweight and obese postmenopausal women:a randomized, controlled trial
There is a debate over the independent effects of aerobic fitness and body fatness on mortality and disease risks. Purpose: To determine whether a 25% energy deficit that produces equal change in body fatness leads to greater cardiometabolic benefits when aerobic exercise is included. Methods: Thirty-six overweight participants (16 males/20 females) (39 ± 1 yr; 82 ± 2 kg; body mass index = 27.8 ± 0.3 kg-m2, mean ± SEM) were randomized to one of three groups (n = 12 for each) for a 6-month intervention: control (CO, 12.5% reduction in energy intake plus 12.5% increase in exercise energy expenditure). Food was provided during weeks 1-12 and 22-24. Changes in fat mass, visceral fat, V O 2 p e a k (graded treadmill test), muscular strength (isokinetic knee extension/flexion), blood lipids, blood pressure, and insulin sensitivity/secretion were compared. Results: As expected. VO2p e a k was significantly improved after 6 months of intervention in CR + EX only (22 ± 5% vs 7 ± 5% in CR and – 5 ± 3% in CO), whereas isokinetic muscular strength did not change. There was no difference in the losses of weight, fat mass, or visceral fat and changes in systolic blood pressure (BP) between the intervention groups. However, only CR + EX had a significant decrease in diastolic BP ( – 5 ± 3% dvs – 2 ± 2% in CR and -1 ± 2% in CO), in low-density ipoprotein (LDL) cholesterol (-13 ± 4% vs – 6 ± 3% in CR and 2 + 4% in CO), and a significant increase in insulin sensitivity (66 ± 22% vs 40 ± 20% in CR and 1 ± 11% in CO). Conclusions: Despite similar effect on fat losses, combining CR with exercise increased aerobic fitness in parallel with improved insulin sensitivity, LDL cholesterol, and diastolic BP. The results lend support for inclusion of an exercise component in weight loss programs to improve metabolic fitness.
Caloric Restriction with or without Exercise The Fitness versus Fatness Debate
This review includes an historical overview of the techniques for measuring energy expenditure (EE). Following this overview, the ‘gold standard’ method of measuring EE, the doubly labelled water (DLW) method, is emphasised. Other methods, such as direct calorimetry, indirect calorimetry systems, heart rate and EE relationships, questionnaires and activity recall, motion sensors, combined heart rate and motion sensors for the estimation of EE are then highlighted in relation to their validation against the DLW method. The major advantages and disadvantages for each method are then considered. The preferred method to determine EE is likely to depend principally on factors such as the number of study participants to be monitored, the time period of measurements and the finances available. Small study participant numbers over a short period may be measured accurately by means of indirect calorimetric methods (stationary and portable systems). For periods over 3–4 days, EE should ideally be measured using the DLW method. However, the use of motion sensors is very promising in the measurement of EE, and has a number of advantages over the DLW method. Furthermore, if used correctly, both heart rate and questionnaire methods may provide valuable estimates of EE. Additional studies are needed to examine the possibility of improving the accuracy of measurement by combining two or more techniques. Such information, if confirmed by scientific rigour, may lead to an improvement in the estimation of EE and population-based physical activity levels. The accurate measurement of physical activity and EE is critical from both a research and health prospective. A consideration of the relevant techniques used for the estimation of EE may also help improve the quality of these frequently reported measurements.
Estimating Human Energy Expenditure
Maximal weight loss observed in low-calorie diet (LCD) studies tends to be small, and the mechanisms leading to this low treatment efficacy have not been clarified. Less-than-expected weight loss with LCDs can arise from an increase in fractional energy absorption (FEA), adaptations in energy expenditure, or incomplete patient diet adherence. We systematically reviewed studies of FEA and total energy expenditure (TEE) in obese patients undergoing weight loss with LCDs and in patients with reduced obesity (RO), respectively. This information was used to support an energy balance model that was then applied to examine patient adherence to prescribed LCD treatment programs. In the limited available literature, FEA was unchanged from baseline in short-term (12 wk) treatment studies with LCDs; no long-term (26 wk) studies were found. Review of doubly labeled water and respiratory chamber studies identified 10 reports of TEE in RO patients (n150) with long-term weight loss. These patients, who were weight stable, had a TEE almost identical to measured or predicted values in never-obese subjects (weighted mean difference: 1.3%; range: 1.7– 8.5%). Modeling of energy balance, as supported by reviewed FEA and TEE studies, suggests that obese subjects participating inLCDprograms have a weight loss less than half of that predicted. The small maximal weight loss observed with LCD treatments thus is likely not due to gastrointestinal adaptations but may be attributed, by deduction, to difficulties with patient adherence or, to a lesser degree, to metabolic adaptations induced by negative energy balance that are not captured by the current models.
Why do obese patients not lose more weight when treated with low-calorie diets? A mechanistic perspective
How much may I eat? Most healthcare workers, when asked this question, have insufficient knowledge to educate their patients on a healthy energy intake level. In this review we examine the available methods for estimating adult energy requirements with a focus on the newly developed National Academy of Sciences/ Institute of Medicine (NAS/IOM) doubly-labelled water total energy expenditure (TEE) prediction equations. An overview is first provided of the traditional factorial method of estimating energy requirements. We then extend this overview by exploring the development of the NAS/IOM TEE prediction models and their role in estimating energy requirments as a function of sex, age, weight, height and physical activity level. The NAS/IOM prediction models were developed for evaluating group energy requirements, although the formulas can be applied in individual ‘example’ patients for educational purposes. Potential limitations and interpretation issues of both the factorial and NAS/IOM methods are examined. This information should provide healthcare professionals with the tools and understanding to appropriately answer the question, ‘How much may I eat?’
How much may I eat? Calorie estimates based upon energy expenditure prediction equations
Sports nutrition is a constantly evolving field with hundreds of research papers published annually. For this reason, keeping up to date with the literature is often difficult. This paper is a five year update of the sports nutrition review article published as the lead paper to launch the JISSN in 2004 and presents a well-referenced overview of the current state of the science related to how to optimize training and athletic performance through nutrition. More specifically, this paper provides an overview of: 1.) The definitional category of ergogenic aids and dietary supplements; 2.) How dietary supplements are legally regulated; 3.) How to evaluate the scientific merit of nutritional supplements; 4.) General utritional strategies to optimize performance and enhance recovery; and, 5.) An overview of our current understanding of the ergogenic value of nutrition and dietary supplementation in regards to weight gain, weight loss, and performance inhancement. Our hope is that ISSN members and individuals interested in sports nutrition find this review useful in their daily practice and consultation with their clients.
ISSN exercise & sport nutrition review: research & recommendations