It is healthiest to lose weight at a rate of 1-2 lbs. per week. It is okay to lose 3-5 lbs. per week generally speaking in a short term span, but on a healthy long term weight loss plan, it is best to average 1-2 lbs each week.
The reason why is because of several key things. First, when you embark on a weight loss goal, "how much" weight you lose is not as important as "what kind" of weight you lose. If you lose muscle mass weight in the process, this is counterproductive from a health standpoint. Not only is muscle important for strength, movement, and protective support to the body, but it is also responsible for elevated RMR, resting metabolic rate.
RMR elevation is important for long term health and weight loss. It is essentially how quickly your body burns calories and fat while you are resting, not exercising. The more muscle mass you have on the body, the greater your RMR will be. So if you lose muscle mass during a weight loss program, in the long run, not only do you decrease your strength, resulting in greater cause for injury, you also decrease RMR, resulting in greater long term fat storage (basically, any of the weight you lose will eventually all go back on and probably more.)
Muscle mass weight is usually lost in two main ways on a weight loss plan. One is by crash dieting, also known as starving yourself. This is when you cut your calories so low, particularly combined on an exercise program, and your body starts to break down muscle for energy as a result.
Another way to lose muscle weight is to do too heavily a cardiovascular training regimen to lose weight. Say you do an hour of running a day, five days a week, with no resistance training, and you keep your calories relatively low while you do. What will happen is your body will begin to break down muscle for energy, another catabolic process.
Another important reason why 1-2 lbs a week is the healthy recommended weight loss average recommended, in addition to muscle loss, is for daily functioning. If your calories are too restricted, or your energy output by doing too much cardio is too great, you will not have enough energy, vitamins, and nutrients to healthily function on a daily basis. This can interfere with daily energy, mood, concentration, and therefore productivity at work.
Stick with 1-4 lbs. per week max on your weight loss plan to ensure you stay healthy in the process and also keep the weight off in the long run.
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