What is better for weight loss (considering time / efficiency)? Cardio or Weight Training
If time is a consideration, your best bet is cardiovascular activity. This has been backed up by studies in MASS and the Journal of Applied Physiology (see below). Keep in mind though, when doing these studies individuals are being put through a basic, lower intensity / volume of training. In general, these were beginner level trainees. As such they are not going to be burning nearly as many calories when compared to an equal amount of time performing cardio.
Cardiovascular health in overweight / obese individuals is not that good. Furthermore, the body quickly acquires adaptations when first introducing cardiovascular exercise, even if just adding in walking. Over the lifespan of an individual, once some of the body fat is lost and they are closer to a natural set point, then adding lean mass (muscle) is going to have a significant impact. However, from the perspective of an overweight person with a limited amount of time (reality or perceived) it has been scientifically shown in studies that cardiovascular exercise is more beneficial in caloric burn. And, applying the law of thermodynamics, this equates to more weight loss (fat).
What about someone whom doesn’t have a lot of body fat to lose?
The biggest impact to their physique will be made through weight training. You cannot change your shape, or aesthetic look, without some form of progressive overload / resistance training. Dialed in dietary habits and cardio are NOT going to change your muscular shape or “look”. This may not be your focus, so the “it depends factor” applies to the overall equation.
In general, the optimal approach is specific to the individual. If the goal is to have the most impact visually on a lean person, then weight training should be considered. If time is a factor, and you are very overweight, then paying attention to your diet and focusing on cardio may be a better success path for you.
What about a balance of both?
The cited study shows similar benefit in weight loss but added benefit of body composition change (lean mass) with the addition of weight training. Don’t rely on just the scale. Changes in body measurements, physical look and the ways clothes fit are all indicators of progress that may not be readily apparent on the scale. In the study however, they were nearly the same when looking exclusively at weight loss.
It is advised to seek a lifestyle change, or better put sustainability. We can put someone whom is overweight on super low calories and a high workload of cardio (think Biggest Loser) and they are going to drop weight. The problem is how sustainable, and healthy, is that? We cannot sustain extreme caloric deficits or exercise regimens, and risk negative hormonal adaptations and other disorders. What we can maintain is a healthy dietary approach with moderate levels of activity (weight training, cardio).
Food for Thought:
If you aren’t losing fat fast enough, or feel stuck, the first place to look is in your nutrition and not to include more exercise. In my opinion, on a basic level cardio is more of a short-term strategy for fat loss, while weight training is a long-term approach to maintaining lower body fat levels.