Resistance training alone unlikely to end in fat or weight loss.
I have served as a military officer for over twenty years. In the military, the belief that the key to maintaining a healthy weight is exercise. If you are overweight, commanders often punish those who fail to make weight standard with extra exercise. One type of exercise is resistance training and the other is exercise. It is believed that resistance training will decrease fat mass, and increase lean body mass, which is believed to help with weight loss maintenance. It is hard for me to believe that they might have it so wrong, but the research is often conflicting.
A recent study looked at resistance training as a means to lose weight (body fat) and keep it off. Researchers sought to examine the effects of a 1-year RT intervention on weight loss maintenance following a 6-month dietary weight loss intervention. Following the 6-month dietary weight loss intervention, the subjects, consisting of 70 postmenopausal overweight or obese women, were randomized to a control group or a resistance training group. After completion of the trial, subjects in both groups experienced significant body fat and weight regains and there was no significant difference at 1-year post-intervention. Resting energy expenditure and total daily energy expenditure did not change after the weight maintenance phase. In fact, both groups had significantly greater than the predicted decrease in resting energy expenditure after the 6-month dietary intervention and at the end of the 1-year weight-loss maintenance phase. This probably explains the weight regain.
The bottom line: Resistance training did not improve body composition or energy expenditure during a 1-year weight maintenance program. I would still recommend both cardiovascular and resistance training if you are trying to lose or maintain weight loss. It may not help keep the weight off in the long run but it certainly is good for you heart and overall health.