Losing body fat as quickly and efficiently as possible
requires a three-pronged approach: (1) balanced nutrition
from natural foods, (2) aerobic training, and (3) weight
training. All three ingredients are essential. If you neglect
any one of these components, it will compromise your results
because you lose the "synergy" created from this
In "The Seven Habits of Highly Effective People" Author Steven Covey wrote, "Synergy means that 1 + 1 may equal 8, 16, or even 1600. Synergy is everywhere in nature. If you plant two plants close together the roots commingle and improve the quality of the soil so that both plants will grow better than if they were separated. If you put two pieces of wood together they will hold much more than the total of the weight held by each separately. The whole is greater than the sum of its parts."
When you include weights, cardio and balanced nutrition in your fat loss regimen, the effects of the three parts brought together are not linear, they are exponential. Each part complements the others and multiplies your results. You develop an efficient metabolism and a lean, muscular body that could not be achieved with one or even two of the components in isolation.
The best you can hope for from diet and aerobics alone is to become a "skinny fat person." You may lose weight from diet and aerobics, but much of it will be muscle, your fat to muscle ratio will plummet and you will take on a "soft" appearance. It's not uncommon for a woman 5 feet 4 inches tall to weigh 125 pounds and yet have 25-30% body fat. According to the Metropolitan Life height and weight tables, 125 pounds is ideal for a medium-framed 5’ 4" female, but 25-30% body fat is extremely poor for anyone! Without the weight training, you will never optimize your muscle to fat ratio and you will always struggle to keep fat off permanently.
If you have extremely limited time, and your main priority is to lose fat, then you can keep your weight training brief - maybe 30 minutes 3 days per week - and spend the rest of your time concentrating on cardio. But never neglect the weights completely - always do both, and if possible, devote an equal amount of attention to each.
Last, but not least, don't forget that weight training, not cardiovascular training, is "shapes" and sculpts your muscles. Simply put, lifting weights makes you look better! If you want a lean, hard, fat-free body, then get out of the aerobics studio, get off that bike or treadmill, and pick up some barbells and dumbbells! Lifting weights isn't just for "muscle-heads" anymore.