Q: can you lose 3 pounds a week?

A: You can certainly lose 3 pounds of weight per week, but for most people that would be counterproductive. Even though we always talk about 'losing weight', we really want to lose FAT, not just weight. It is fat that gives us the flabby chunky appearence and it is extra fat that carries a host of potential health problems.

So the question then becomes: can you lose 3 pounds of FAT in a week? For most people the answer would be NO, or at least NO, for more than a couple of weeks. When you have aggressive fat and weight loss like that, your body will be simultaneously losing a lot of muscle (which your body can and does burn for energy, just like it does with fat). When you lose muscle quickly with severe calorie restriction like you'll need for fast fat loss, your metabolism will very quickly shut down and fat loss will grind to a halt.

So you might go one week losing 6-7 pounds of which 3 are fat, then another week losing 3-4 pounds of which 1-2 are fat, and that's it. Past that second week your weight loss and especially fat loss will be minimal, if any. And soon enough, because you've lost all that muscle and lowered your metabolism, the fat that you lost comes back, usually with extra! This is by far the most common scenario for countless fad diets and this is the reason none of them work in the long-term. They give you seemingly great results quickly, which soon enough stop, and soon after that reverse with all the fat coming back.

If you're very severely overweight or obese, 3 pounds per week may be an OK weight loss pace, but for most people who just need to lose 20 pounds of fat or so, trying to lose it so quickly will backfire. For an average person I recommend losing weight and fat at about 1 pound per week and certainly no faster than 2 pounds per week.