Great question!
First off, both are great for a healthy life, with that being said, if we are only talking about weight loss or more specifically, fat loss, most forms of exercise are completely inefficient. Before I continue, I need to say, if you love doing yoga, keep doing it! Do what you love! But if you want to just talk about fat loss, I'll over simplify a complex answer.
1. Any form of exercise that is consistent over a period of time qualifies as aerobic exercise. Aerobic is the most inefficient form of exercise for fat loss.
2. What form of exercise melts fat 24/7 even when you're not working out? High-Intensity Interval Workouts (or commonly known as HIIT). Why? Basically, Exercise Post Oxygen Consumption or EPOC. This means when you do cardio, you burn calories, but when you stop exercising, you stop burning calories. When you do a proper HIIT workout, studies should you can still burn calories up to 48 hr after your workout!
What are HIIT workouts? There are great posts found on this forum and others, and all over the web on HIIT workouts. Basically its intervals of any form of exercise. For example, run 100% sprint for 10 secs, take a 30-second break and repeat 10 times. It can really be anything you want, but the most important aspect is giving it 100%, not 90% or 50%! It doesn't work unless you give it your all. Another example could be riding the stationary bike: 15 sec on/10 sec off for a set of 10. Literally becoming a 10 min workout, AND it burns more fat than an hr of running or yoga! Cool!
3. To top off the list of fat burning exercises: Weight training! Yes, studies show lifting out-performs HIIT workouts. Why? For the same reason HIIT out-performs cardio. And if you are afraid that lifting will make you big, it won't! Trust me. If you are eating well, as a female, you don't have enough testosterone and other hormones to 'get big'. If you are worried, stick to higher reps and a shorter break between.
4. At the end of the day, the most proven way to lose fat the fastest and keep it off is your diet change! Studies show that 80% of your results will come from your change in diet. So eat SMART and well-balanced meals!
I hope that helps and keep doing yoga too!
- To Your Success