Fast weight loss plans may help you drop pounds, but they're not always safe or lasting. Here's how much is safe and sustainable—plus how to shed weight the smart way.

Fast weight loss promises—lose 20 pounds in four weeks!—aren't really our thing. But we understand the allure. After all, it's a rare person who hasn't Googled "can I lose 10 pounds in two months?" or maybe even "can I lose 10 pounds in four weeks?" in advance of a high school reunion, wedding, or another major event at least once. Deadlines await, you know? While we know enough to ignore quick-and-dirty, fast-fix, starvation diets, though, what about healthy weight-loss plans—how much can you really expect to lose in 30 days? And how long does it take to lose 10 pounds—safely and in a way that's sustainable?

Get out your calculators and follow along because the answer to this question is all about numbers.

In one month, you can reasonably anticipate losing eight to 10 pounds if you follow a pretty strict plan. (So, your Q about if you can lose 10 pounds in two months? The answer is yes!) Losing one pound of body fat is equivalent to 3,500 calories. To lose two pounds per week, you must drop 1,000 calories per day. That means cutting the calories you eat, increasing the number of calories burned during your workout—or, most likely, doing some combination of both.

(This advice to lose 10 pounds in four weeks or so only works if you're taking in too many calories to begin with, though. If you've already been on a low-calorie diet, you may need to up your intake to see healthy results. Case in point: This rockstar.)

If you're looking to cut calories in the kitchen, a daily food journal is clutch. This can be as simple as a piece of paper or a phone app like MyFitnessPal. Logging every morsel that goes in your mouth might seem tedious, but it's a proven way for dieters to see patterns like mindless snacking and overeating during stressful times, both of which can lead to additional calories consumed. Dropping 1,000 calories per day may seem daunting, but if you think about it in terms of second helpings, pieces of bread, pats of butter, raids of the cookie jar, etc., it's easy to see where you can make small changes to pare down that number. For instance, these 30 easy strategies all help you drop 100 extra calories from your diet fast.

If you're looking for a calorie-burning assist from the gym, aim for a moderate workout five to six days per week. The number of actual calories burned will be determined by your sex, weight, how fast you did the exercise, and how long you did it. Here are just a few general examples based on a person who weighs 150 pounds. (Bonus: How to Burn 500 Calories in 30 Minutes)

Running on the treadmill for 20 minutes at 6 MPH: 229 calories

229 calories Working out on the elliptical for 30 minutes: 179 calories

179 calories Swimming breaststroke for 30 minutes: 189 calories

189 calories Kickboxing for 30 minutes: 357 calories

So how long does it take to lose 10 pounds or any amount of weight for that matter? The answer depends on how many of the above strategies you try—and feel like you can stick with for a lifetime. Anyone who's tried juice cleanses or crazy detoxes knows what it's like to fall off the wagon and rebound after; not exactly the goal for achieving and maintaining a healthy weight.