Have you ever wanted advice from a personal trainer on choosing between training with free weights versus fixed weights? There are positives and negatives for each type of exercise, so it helps to have a goal in mind when choosing a routine. For instance, many people just starting out with a strength training routine feel more comfortable with machines - that in itself is a benefit if it gets people to exercise more. If you are set on getting the most out of your time in the gym and if your main goal is weight loss, then free weight exercises are going to give the most bang for your buck.
The main reason for improved weight loss is that free weight exercises are often performed standing up with the weight supported by the entire body. This ends up taxing a larger portion of your whole body musculature than you will get with a machine based exercise. When your muscles are recruited for force production there is an energy requirement associated with that action. Because your body stores energy as fat, the best way to get rid of it is to create increased energy demands through more activity (strength training workouts, cardio, hiking, sports, etc.). So naturally, you want to involve as many muscles as you can during your workouts to create a net effect resulting in weight loss.
There is a second reason that I consider free weights better for fat loss - they more closely simulate real life activity. When you perform a squat at the gym, that movement pattern is very similar to how you would normally squat and exert yourself in real life. Think of the preparation squat before jumping up to hit a volleyball. Preparing your body for real life activity will make you more likely to participate in additional activities outside of the gym. A more active lifestyle overall should be your ultimate goal to insure weight loss for the long term.
There are many reasons other than weight loss that free weights can be a good choice for your strength training routine. For example, free weight exercise promotes bone mineralization that helps to prevent osteoporosis later in life. So don't just think of free weights for weight loss, consider the many benefits of training with free weights. You can get more info on the debate over machines vs free weights by checking free weights versus fixed weights [http://www.fitness-answers.com/free-weights-versus-fixed-weights.html].
Before starting a routine with free weights consider some instruction from an experienced personal trainer to minimize the chance of injury and to insure maximum results from your workouts.