It's a given that effective weight loss is much more then simply going on a "diet". To really lose weight and (hopefully) keep that weight off, you need to add exercise to the equation. For Most people, weight loss exercise means aerobics ? running, jogging, kickboxing or some other type of routine where you get your heart racing for 30 to 45 minutes.

It's true, that one hour of aerobic exercise probably burns more calories than one hour of weight training. However, the calories burned during exercise are only part of the story. When you're finished lifting weights, your muscles need repair themselves; this repair process burns additional calories. Further, the result of this repair process is additional muscle mass, and guess what --muscles burn calories, even if you're just sitting around. Recently, Curves' Fitness centers revealed the results of two separate studies that prove just that. The studies showed that participants were actually burning, on average, an additional 265 calories per day, because of the additional muscle mass. Meaning they could actually eat more everyday without gaining weight!

Want to really pack some muscle on? Try adding these three exercises to your fitness routine. All three are "compound exercises" meaning they work multiple muscles simultaneously.

The Squat: One of the toughest exercises you can do, the squat, as its name implies, involves squatting down to an almost sitting position, then pushing yourself back up. Squats can be performed with or without added weights. Simply stated, the squat packs muscle on your lower body, muscle that will be burning calories for you, even while you sleep.

The Deadlift: Another great lower body exercise that also hits your shoulders and arms. Using a barbell, you start in an almost kneeling position, keeping your spine straight. You grip the weight(s) about shoulder width apart, then slowly push up until you're standing with the weight at about waist level. After a momentary pause, you slowly lower the weight back to the starting position.

The Bench Press: Here we work the upper body, especially the chest and shoulders. This exercise can be performed using either a barbell or dumb bells. You start by lying on a bench, grip the weights at about shoulder width, press up until just before your arms lock, then slowly lower the weight back to the starting position.

All three of these great exercises have multiple variations; beginners should start with very low weight and practice the exercise to get proper form. Better yet, invest in an hours worth of personal trainer time and have him/her get you started and help you develop an ongoing plan.

David Olsen is the founder of 40Something Fitness, the website that helps you defy middle-age. Visit us for more muscle and fitness articles today.