Choosing a goal body weight can be a daunting task, especially if you’re not sure what qualifies as a healthy weight or haven’t been at a healthy body weight since you were a child or teen. While it may seem productive to choose an ideal goal weight and work toward that goal, the truth is that your “ideal” body weight may not be achievable based on factors such as your height and personal health.

Choosing a realistic goal weight can help you gain a better perspective on what you need to do to accomplish your weight-loss goals. On the other hand, choosing an unrealistic goal weight can be disheartening and discouraging, especially if you do everything in your power to meet your goal through diet and exercise, but just can’t seem to reach your ideal weight.

So how do you go about choosing a realistic goal weight? A recent British study may have the answer. The new study, which was published in the Journal of Human Nutrition and Dietetics, revealed that most women tend to have unrealistic expectations about weight loss.

The study involved a group of women who weighed an average of 152 pounds. These women said they considered 123 pounds to be a “happy” weight, while also admitting that they feel 132 pounds is a more realistic and achievable goal weight. If women already know 132 pounds is achievable and more realistic, why are they so intent on losing the extra nine or 10 pounds?

Dawn Jackson Blatner, RD, author of The Flexitarian Diet, says shows such as The Biggest Loser are giving people the impression that weight loss can happen quickly within a short period of time. However, these shows are often taped over the course of several months, and contestants may spend hours per day focused on exercise and nutrition. As a result, any type of weight loss can seem disappointing to dieters who get caught up in the media, thinking that they’re not losing enough weight within the proper amount of time.

To find your target weight, the first step is to write down three numbers: the highest weight you’ve ever been, the lowest weight you’ve ever been as an adult, and a number between these two weights that you might have weighed during a time you were eating healthy and reasonably without focusing too much on obsessive dieting.

Keri Glassman, RD, says to focus on the weight your body is normally at when you’re just an average, healthy person, then subtract five pounds from that third number to get your ideal target weight. For example, if your highest weight was 220, and your lowest weight was at 130 in your early twenties, think about a number in between during which you were active and eating well. If that number is 150, subtract five pounds to get a goal weight of 145. Glassman says that in most cases, this particular formula produces a goal weight that is completely healthy and achievable.

What’s the ideal rate at which you should be losing weight? Blatner says to aim to lose between one-half to two pounds per week. In the beginning, you may lose between three and five pounds if you’ve recently switched to eating healthier foods and are exercising regularly. But on average, weight-loss success can stay consistent if you’re losing at least a half pound per week.