A Fitness Trainer Shares 9 Reasons You're Struggling to Lose Weight (and How to Fix It!)

All those extra bites, licks, and tastes can add up to hundreds of extra calories. "Take a week or two and really try not eating anything outside your planned meals and/or snacks," suggested Marci. If it goes in your mouth, track it, just to see how it affects your daily calories.

"It doesn't matter if you're perfect Monday-Friday, overeating on the weekend can undo all the progress you made the days before," Marci said. Instead of being strict all week, you might do better allowing yourself a little treat every day, and that could prevent overeating on the weekend.

A handful of almonds here, a spoonful of peanut butter there, a drizzle of olive oil on your salad — these are all healthy foods, but be mindful of healthy foods that are calorie dense. "Nuts and nut butters, olive and coconut oil, avocado, etc. while all healthy, pack a big caloric punch." Marci added, "Not to say don't eat them, but do be mindful of how much you're eating."

Saying you ate "half an avocado," could mean anything, since calories range between sizes. "A heaping tablespoon instead of a leveled one can be the difference in at least 50 extra calories," Marci said. If you want to be precise about what you're eating, measure your food with a scale. You don't have to do this forever, but a week or two of accurately measuring your food can be eye-opening.

Exercising does build muscle and burn calories, so you think more is better, right? "Not giving your body days off to recover can increase cortisol," Marci said, which can make it harder to lose weight. NASM-certified personal trainer and NPC bikini competitor Dee Gautham told POPSUGAR "Elevated cortisol levels result in many negative symptoms, like feeling fatigued, poor sleep, water retention (which can make you feel bloated and actually mask fat-loss), poor immune system functionality, and much more."

Rest days help your body repair and recover. Dee added, "If fat loss is your goal, taking a day to rest your muscles and restore your energy can help you push harder in the gym the next day, so you can get to your fat loss goal more efficiently." She said that a beginner just starting to work out might need two to three rest days a week, while a more experienced athlete might be fine with one day.

If you're kicking butt in the gym for an hour, but sitting on your butt the rest of the day, then you're probably not burning as many calories as you think. NEAT stands for nonexercise activity thermogenesis, and it's the calories you burn moving around throughout the day (not through exercise). Increasing NEAT will increase your metabolic rate, burning more daily calories, which will help you lose weight.

"You can't diet forever without your metabolism slowing down, meaning you'll be burning fewer calories overall," Marci explained. "When you need a break depends on how long you've been dieting and how much weight you have to lose. But a period of 1-2 weeks at maintenance for every 2-12 weeks of dieting is a good place to start."

Chronic inflammation from too much exercise or from certain foods can also increase cortisol levels, which "can wreak havoc on not only your weight-loss results but your health in general," Beachbody trainer Autumn Calabrese told POPSUGAR. Be sure to incorporate rest days, take time for self-care like foam rolling and stretching, and eliminate foods like sugar, dairy, wheat, corn, and soy if you're sensitive to them.

Stress plays a big role in creating a leaner waist because it triggers the production of cortisol, which is a stress hormone that's linked to an increased appetite and more belly fat. Sleep and weight gain are also closely linked since a lack of sleep will raise cortisol levels, as well as grehlin (hunger hormone), and increase cravings, so you eat more. Find healthy ways to relax and bring more joy to your life each day, and aim to get seven to nine hours of sleep nightly.

"Feel like you're doing everything right yet the scale just won't seem to budge? If you're frustrated with your fat loss progress, you might be making one, or many, of these mistakes," Marci said.