Losing 10 pounds in 3 weeks is doable if you are ready to put an extra effort and stay committed towards the goal. It is not recommended if you are already at a healthy weight. This falls under the category of short term goal where you will have to shed weight for an upcoming event. If you are mindful about what you eat and minimize the alcohol consumption you will positively start experiencing the weight loss happening. For genuine weight loss to happen diet and exercise should go hand in hand.
There are even weight loss programs that help you achieve this goal but you will have to be careful in choosing the one. Programs that offer a weight loss result at a steady rate are highly recommended to stay away from health complications. Nutriystem is a well known diet program that offers safe weight loss at a steady rate. It does not believe in rapid weight loss and focuses on portion control which is a successful strategy that most of the popular weight loss programs use in the market. It has recently launched a plan called Turbo 13 which is specifically designed to accelerate the weight loss process in dieters. By following this plan, the dieters will be able to lose up to 13 lbs and 7 inches in the first month. Have a look at http://www.alabama-reading.org/ the clearly explains the Nutrisystem and its way of operating.
As a first step towards you goal you will have to arrive at the daily calorie need. You need to arrive at a number that is below the number what you burn. Losing one pound requires you to create a deficit of 3500 calories. Therefore to lose 10 pounds you will have to create a deficit of 350000 calories in 3 weeks. This translates to creating a deficit of 1666 calories per day. You can effectively combine diet and physical activity to arrive at this deficit and achieve the goal.