There's no magical program that will lead to weight loss on its own. To lose weight you need to burn more calories than your body consumes. The circuit-style, high-intensity workouts provided by CrossFit crank up your heart rate, activate multiple muscles and provide a big calorie burn. If your calorie consumption doesn't negate what you burn, CrossFit will help you lose weight.
How Weight Loss Works
To lose a pound of fat you need to burn 3,500 calories more than you consume. A safe way to reach the number is by reducing your caloric intake by 250 each day, and burning 250 calories through exercise. The 500 calorie deficit will equal one pound per week. The American Council on Exercise conducted a study that showed some CrossFit workouts can burn between 12 and 20 calories per minute. In a 30-minute session this works out to a burn of 360 to 600 calories. As long as your diet does not replace those calories CrossFit will cause weight loss.
Building Muscle to Burn
Muscle is active tissue which burns calories even at rest. So the more muscle tissue you have, the bigger your calorie burn will be on a daily basis. CrossFit utilizes multiple muscle groups through compound exercises, and the activation of multiple muscles will burn more calories than activating a single muscle at a time. If you recover properly and build the desired muscle tissue, this will can aid weight loss.
How long your body requires for recovery will largely depend on your current fitness level. High-intensity workouts, like CrossFit, can sometimes damage the skeletal muscles, and if these muscles don’t adequately recover you will not be able to perform at your peak until they do. If you can't perform your best, you ability to burn calories and lose weight may be hindered. Recovery doesn’t always mean time off, and sometimes your body just needs a break. Every couple of months spend a few weeks doing low-intensity resistance and cardio training before jumping back into a high-intensity workout.
Fueling to Prevent Muscle Loss
Your body will burn muscle for fuel if it is not adequately fueled. ACE Fitness says that eating a steady diet of lean protein and amino acids will help minimize your body’s tendency to resort to eating muscle tissue. The CrossFit nutritional page recommends reducing your sugar and simple carbohydrate intake, but increasing your fruit, vegetable, complex carbohydrate and lean protein intake.