Both types of training are required for general health maintenance, as well as to lose weight. Think of it this way, strength training adds lean muscle. Lean muscle burns more fat during rest – thus increasing your basal (resting) metabolic rate. This increase in basal metabolic rate can positively offset the decrease in basal metabolic rate that dieters often see once their body goes into ‘save everything mode.’ It’s a good way to keep your metabolism up, while slimming calories from your daily intake.
Cardio exercise (if in the aerobic, or fat burning, state) is known to burn calories from fat. This is a great way to create a caloric deficit, & combined with some caloric reduction in terms of what you eat, will create the total caloric deficit you need to steadily lose weight.
Not to mention the vast health benefits of a balance exercise routine that includes both resistance (strength) training & cardiovascular training – good for bone health, heart health, and as a way of preventing the onset of some major illness. You’ll sleep better, feel better, and look better, too!
Good luck in your training.
I highly recommend doing both by alternating days of cardio/strength training. As a Wellness Coach, I am interested in overall health for my clients (most of which are in need of fat-loss). For heart health, cardiovascualar training is best, however, working your muscles burns more fat for alonger amount of time. Even though you might not see the pounds come off as quickly, you will lose inches immediately.
For the majority of my clients I create a personalized strength and core training routine and have them do “Peak 8” twice a week. This gets in their cardio training (and burns as many calories in 19 minutes as 2 hours of cardio, per research by Dr. Mercola) and helps the body produce large amounts of the Human Growth Hormone (HGH), which helps with the aging process, inside and outside of the body.
So, to answer your question, I would say that you need both types for overall health, wellness, and fat-loss.