Many people take up running in the hopes of shedding weight, only to find that after weeks or months of effort, the number on the scale has barely budged. Or worse, the number has actually gone up.

“I’ve had people say, ‘Why am I training for a marathon and I’m gaining more weight than I ever have?’” says Tom Holland, certified strength and conditioning specialist, exercise physiologist, certified sports nutritionist and author of “The Marathon Method.”

If you’re frustrated by a lack of results, chances are you’ve fallen into one (or several) of the following common running traps. Here is what you need to do to get your progress back on track.

“When people start to exercise they tend to eat a little more, partly because of increased energy needs, but mostly because it is easy to justify,” says Steve Ball, PhD, a professor of nutrition and exercise physiology at the University of Missouri.

In other words, that 8-mile run you just finished can feel like good justification for splurging on a donut (or two). While the occasional treat isn’t a big deal, you could end up canceling out your workout entirely if you don’t watch it.

What’s more, people often assume they’re burning more calories than they really are. For example, in one study, published in the Journal of Sports Medicine and Physical Fitness, people overestimated calories burned during a treadmill session by as much as four times the actual amount, leading them to eat 2–3 times their caloric expenditure from that workout.

As a general rule, you can expect to burn roughly 100 calories per mile, Holland says, though exact numbers may vary depending on weight, sex, age and fitness level. In fact, some estimates dictate a 30-minute run at a speed of 6 miles per hour (a 10-minute mile) can torch 300–444 calories, depending on your weight.

But knowing how many calories you burn on each run won’t do you much good if you don’t also know how many calories you need per day to lose weight.

Use the calculator at the dropdown menu on fitness to determine your daily caloric needs and your basal metabolic rate (BMR) — how many calories you burn at rest. Generally, you want to aim for no more than 500 calories under your BMR for a new daily total that encourages healthy fat-loss. This way, you can be smarter about manipulating your exercise and/or diet to meet that total.

Just be careful not to drop your caloric intake too low or run miles on top of miles — all for the sake of weight-loss. If you find your daily calorie allotment is leaving you feeling sluggish, moody or sleep-deprived, give yourself some more calories.

Either way, start paying attention to how much you’re actually eating and burning per day. “I think most people would be really surprised,” Holland says. He recommends keeping a food log so you become aware of your actual intake. If you have the funds, you could also consult with a sports nutritionist who can provide you with a personalized eating plan.

Another common mistake many runners make is they become so addicted to running that they never try other activities. “That’s a huge problem,” Holland says. “If you do the same thing over and over, it doesn’t matter how healthy it is, you’re going to get injured.”

Varying your training helps you become a more resilient runner, which allows you to continue seeing both performance and weight-loss progress. Strength training in particular makes a great addition to any running program. In fact, performing a combination of cardio and strength training leads to greater weight loss than cardio-only exercise programs, according to a study in BMC Public Health.

“I would definitely recommend including some resistance training in the program if body fat change is the goal,” Ball says, as strength training can help you maintain muscle mass while you restrict calories.

Research backs this up: Elderly obese individuals who strength trained were able to prevent nearly 100% of muscle loss while restricting calories, according to findings published in the journal Nutrients.

Ideally, you’ll cross-train 2–3 days per week with complementary activities like strength training, swimming, cycling and yoga. If you’re overwhelmed at the thought of spending hours in the gym doing non-running activities, keep in mind that a 15–20-minute strength routine and/or a 30-minute swim is sufficient. “It doesn’t have to be long, you just have to be consistent,” Holland says.

When you first started running, it probably felt like the excess pounds just melted away. After a few weeks (or months), however, your results suddenly stop coming. This is because it doesn’t take much for your body to adapt to a new activity, but over time, your body learns how to be more efficient. “The body’s a really smart machine,” Holland says. Unfortunately for you, this means your usual jog around the neighborhood isn’t going to cut it anymore.

If you’re still running the same route at the same pace, you need to start changing things up if you want to continue seeing progress. This could mean kicking up your speed a notch, extending your run another half-mile or mile or choosing a route with more hills. If you have a favorite 3-mile loop, Holland recommends simply reversing your direction. “If you were going clockwise and your loop now goes counterclockwise, suddenly it’s a totally different run,” he says.

Another important thing to remember is once you lose weight, your BMR drops as well, which means you won’t need as many calories as you did when you were heavier. In addition to switching up your usual running routine, be sure to recalculate your BMR every time your weight loss plateaus.

Don’t let a weight-loss plateau discourage you from running. Running offers plenty of great health benefits, from keeping your ticker strong to boosting your mood and quality of sleep. So even if you don’t lose a single pound after a month of dedicated running, keep it up.