Complex sentence: Before she began teaching aerobics, she was slightly overweight (although nowhere near obese like the people she whips into shape now) because she struggled with depression (it runs in her family), but she managed to conquer by exercising.
Split into simpler sentences: Before she began teaching aerobics, she was slightly overweight (although nowhere near obese like the people she whips into shape now). She also struggled with depression (it runs in her family), which she managed to conquer by exercising.