This review evaluates the effectiveness of exercise as a weight loss intervention for individuals with overweight or obesity. A total of 43 studies involving 3476 participants were included. Exercise alone resulted in small weight loss, while exercise combined with diet led to greater weight reduction compared to diet alone. Higher intensity exercise resulted in greater weight loss than lower intensity exercise. Exercise also significantly reduced diastolic blood pressure, triglycerides, and fasting glucose levels, even without weight loss. However, no data were available on adverse events, quality of life, morbidity, costs, or mortality. Exercise is associated with improved cardiovascular disease risk factors, even if no weight is lost. The review found that exercise combined with diet was more effective than diet alone in reducing weight and improving cardiovascular risk factors. However, when directly compared, exercise combined with diet was no more effective than diet alone in reducing cardiovascular risk factors. The review also found that high intensity exercise was more effective than low intensity exercise in inducing weight loss, especially when undertaken without dietary change. However, when diet was also modified, exercise intensity did not significantly affect the degree of weight loss. This may be because the effects of dietary intervention outweighed the effects of exercise intensity. Diet was demonstrated to be significantly more effective at facilitating weight loss than exercise in this meta-analysis. Both low calorie and low fat diets were more effective at facilitating weight loss than exercise alone. This is consistent with other studies that demonstrate dietary modification is superior to exercise in attaining weight loss in overweight and obese adults. The review also found that exercise interventions had positive effects on cardiovascular disease risk factors, including reduced blood pressure, cholesterol, triglycerides, and fasting glucose levels. These changes were independent of significant weight loss. However, weight loss does not appear to uniformly improve cardiovascular risk factors, particularly if 5% or less body weight reduction is achieved. Overall, the review supports the use of exercise as a weight loss intervention, particularly when combined with dietary change. Exercise is associated with improved cardiovascular disease risk factors even if no weight is lost. However, diet alone was more effective than exercise in reducing weight and improving cardiovascular risk factors.This review evaluates the effectiveness of exercise as a weight loss intervention for individuals with overweight or obesity. A total of 43 studies involving 3476 participants were included. Exercise alone resulted in small weight loss, while exercise combined with diet led to greater weight reduction compared to diet alone. Higher intensity exercise resulted in greater weight loss than lower intensity exercise. Exercise also significantly reduced diastolic blood pressure, triglycerides, and fasting glucose levels, even without weight loss. However, no data were available on adverse events, quality of life, morbidity, costs, or mortality. Exercise is associated with improved cardiovascular disease risk factors, even if no weight is lost. The review found that exercise combined with diet was more effective than diet alone in reducing weight and improving cardiovascular risk factors. However, when directly compared, exercise combined with diet was no more effective than diet alone in reducing cardiovascular risk factors. The review also found that high intensity exercise was more effective than low intensity exercise in inducing weight loss, especially when undertaken without dietary change. However, when diet was also modified, exercise intensity did not significantly affect the degree of weight loss. This may be because the effects of dietary intervention outweighed the effects of exercise intensity. Diet was demonstrated to be significantly more effective at facilitating weight loss than exercise in this meta-analysis. Both low calorie and low fat diets were more effective at facilitating weight loss than exercise alone. This is consistent with other studies that demonstrate dietary modification is superior to exercise in attaining weight loss in overweight and obese adults. The review also found that exercise interventions had positive effects on cardiovascular disease risk factors, including reduced blood pressure, cholesterol, triglycerides, and fasting glucose levels. These changes were independent of significant weight loss. However, weight loss does not appear to uniformly improve cardiovascular risk factors, particularly if 5% or less body weight reduction is achieved. Overall, the review supports the use of exercise as a weight loss intervention, particularly when combined with dietary change. Exercise is associated with improved cardiovascular disease risk factors even if no weight is lost. However, diet alone was more effective than exercise in reducing weight and improving cardiovascular risk factors.