Resistance training may provide superior results.
It has long been argued which type of exercise is superior for weight loss. Once camp argues that aerobic exercise is superior because it burns more calories and is better for the heart. The other group argues that resistance training is superior because it burns more calories over a longer period of time as you rebuild the muscle you have exercised.
A recent study from 2017 looked at this very question. The study, “Effect of Exercise Type During Intentional Weight Loss on Body Composition in Older Adults with Obesity” was published in Obesity. The researchers sought to examine the long-term effects of exercise modality on weight loss and body composition and the associations between body composition and physical function changes. The subject of the study were two hundred forty-nine older adults that were 71% women and 32% African American with an average BMI of 34. The subjects were randomized to weight loss, weight loss plus aerobic training, or weight loss plus resistance training groups and followed for 18 months. Data followed during the study included dual-energy x-ray absorptiometry-acquired body composition, 400-m walk time, and knee extensor strength at 6 and 18 months. The study revealed that total body mass loss was enhanced when weight loss was combined with exercise. Total body fat mass lost was significantly greater in the exercise groups (both aerobic and resistance), but less lean mass (muscle) was lost in weight loss with resistance training.
The bottom line: Weight loss with resistance training results in less lean mass or muscle loss than weight loss plus aerobic training or weight loss alone. It is clear that exercise provides an advantage, but resistance training is superior.