Physical activity and the prevention of weight gainД¬hanges in weight are affected by the amount of energy expended versus the amount of energy consumed 17. In the following paper, we will discuss the role of PA and ET in the prevention of weight gain, the expected weight loss from different ET types/modalities, how much PA is necessary to reduce recidivism following weight loss, and further discuss the obesity paradox. Clinicians should consult their patients on what are reasonable expectations based on their specific weight loss program. Overall, the changes in weight in response to ET without caloric restriction are highly heterogeneous and individual differences can span weight gain to clinically significant weight loss 16. A question often encountered in the clinical setting from patients is how much exercise is needed to lose weight and what type of ET should be performed. Strong evidence exists that PA can attenuate weight gain in those at risk for obesity, and many ET programs are capable of producing at least modest weight loss (~2 kg) 15.

The present American College of Sports Medicine (ACSM) recommendations for physical activity to maintain health 9 and promote weight loss 15 are summarized in Figure 1. So above all, clinicians should always encourage their patients to adhere to ET programs or engage in regular PA regardless of the weight loss achieved. Moreover, CRF levels have been shown to alter the relationship of the obesity paradox 14, where high CRF level is associated with greater survival in all body mass index (BMI) categories. Several epidemiological studies even suggest that high levels of PA or CRF attenuates the health risk of obesity 11- 13. High levels of PA and cardiorespiratory fitness (CRF) are inversely associated with CV disease, T2DM and all-cause mortality 10.

High physical activity (PA) levels or exercise training (ET) should be an integral part of any treatment plan for obese individuals regardless of weight loss goals, and is associated with numerous CV benefits 9. Although, the findings of the obesity paradox have been verified in several studies within different clinical populations 6- 8, at the present time, little evidence exists that lower survival is observed in adults with CV diseases after modest or clinically significant weight loss. Recent epidemiological evidence has emerged showing greater survival in adults with CV diseases with higher obesity levels compared to lower levels, which has been coined вЂњthe obesity paradoxвЂќ 5. Thus, a strong rationale exists for clinicians to advocate that overweight and obese patients attempt at least modest weight loss. Clinically significant weight loss (в‰Ґ 5% of baseline body weight) has been shown to be more effective in reducing CV and T2DM risk factors 4.

Weight loss in these patients have been associated with improvements in many cardiometabolic risk factors such as prevalence of the metabolic syndrome, insulin resistance, type 2 diabetes (T2DM), dyslipidemia, hypertension, pulmonary disease, CV disease, and inflammation 3. The American Heart Association's scientific statement on obesity and weight loss 3 recommends weight loss in overweight and obese patients to reduce the severity of CV risk factors. Obesity is a major risk factor for many cardiovascular (CV) diseases such as coronary heart disease (CHD), heat failure (HF), stroke, ventricular dysfunction, and cardiac arrhythmias 3. The total medical cost associated with treating obesity exceeds $140 billion annually, and represents approximately 9.1% of annual medical expenditures 2. In the United States, 66.3% of adults are overweight or obese 1, which represents a major public health concern. Rationale for weight loss in overweight and obese patients

Maintaining healthy disk diet