@servant52 No it is not an efficient way to accelerate weight loss.
Cardio is likely not going to play a major role in your weight loss objective. The way people think about "adding" calories burned through exercise to your total daily energy burn isn't how things actually work. Guess it takes a while for the conventional wisdom to catch up to the science.
If you exercise regularly, your body will quickly adapt--specifically, it will downregulate your basal metabolic rate (BMR) which is your main source of calorie burn (up to 2000 kcal per day). Will also downregulate other stuff like NEAT (non-exercise activity thermogenesis). Or in other words, your BMR goes down so that 300 calories burned exercising don't go as far in terms of getting you a calorie defecit. A lower BMR can reduce the net calories burned from exercise by between 30-90%. And if you're in a calorie defecit already because of your diet, your BMR is even further downregulated--pushing the net calorie defecit down even further.
Of course there's individual variation, so everyone's BMR compensation works somewhat differently. But the point is that the more you exercise--especially if you're already trying to lose weight by dieting--the more your body is working against you.
All the above is why people say you should rely on your diet to drive weight loss--the degree to which exercise contributes to weight loss is very difficult to predict. Making it even more complicated is that activity trackers are notoriously inaccurate--partly because of the metabolic compensation that's occurring, but partly because they're just crap.
