As it turns out, there are a slew of factors that affect weight lossdiet and exercise are only two of them. It also depends on your starting weight, your age, and your gender, says obesity expert Matthew Weiner , MD, bariatric surgeon at Tucson Bariatric. Dr. Weiner explains that the best way to predict how much weight you can reasonably lose with basic dietary and exercise adjustments "is by calculating 10 percent of your total body weight."

For example, if youre starting weight is 150 pounds, you can expect to lose about 15 pounds at first through diet and exercise alone. Beyond that, weight loss can become a tad tougher (though not hopeless!). Your body naturally will begin to resist losing much more weight than around 10 percent thanks to its caveman impulses, explains Dr. Weiner. It will work to maintain your fat and energy stores to preserve your body.

Dr. Weiner notes that younger adults can sometimes lose up to 20 percent of their body weight through straightforward diet and exercise. But for postmenopausal women, for example, it might only be 5 to 7 percent.

Weight loss is also generally less speedy for women compared to men, alas. Men do tend to lose weight faster than women, but when you look at the total amount of weight loss [over time] its not as different as you might think, Dr. Weiner explains. It might take men two to three months to lose 10 percent, while it takes women five to six months. (*Glares.*)

Now that you understand those major physiological influencing factors, here are 20 possible behavioral reasons for why your weight just isn't changingand what you can do to overcome each one. (Psstt, you may be doing one or even a few of these!)

1. Youre way overestimating your muscle weight.

Raise your hand if youve ever thought something like the following after weighing yourself: Im still losing fat, Im just strength training really hard and gaining muscle.

Most of us have done it, but the problem is, Dr. Weiner says it doesnt work that way: Muscle is similar in density to water (while fat has a higher density) so its not an apples-to-apples exchange. In other words, refusing to reevaluate your weight-loss strategy because youre working on building muscle can result in your fat composition staying put.

A good thought experiment is comparing one pound of muscle to a 16-oz. can of soda [which has a similar density], Dr. Weiner explains. Imagine adding that much muscle to your bodyyou would see it.

In other words, you would notice yourself actively building enough muscle to tip the scale toward a higher number...so if you basically look the same, think about something other than muscle gain. Consider tweaking your diet a bit to create a caloric deficit to move the needle, or try HIIT workouts to get your heart rate up and burn fat.

2. Youre eating less...but still picking unhealthy foods.

If you consume fewer calories than you expend, Dr. Weiner says its definitely possible to lose about 10 percent of your total body weight through dieting alone. But if you want to lose more, you cant just keep cutting calories. You have to change the type of food you eat, he says, focusing more on the quality of calories versus the quantity.

For example, if you order in delivery for dinner every night, eating fewer restaurant-prepared meals every week for lunch will probs help you shed some pounds at first...but eventually, the weight loss is going to stop unless you make the switch to even healthier lunches (like made with fewer oils, dressings, etc.) on a consistent basis. Once youve changed the quality of your caloriesand are consuming better-for-you foods with more satiating poweryoull also naturally eat less calories, which can make weight loss continue past the 10 percent point.

3. Youre not keeping track of what youre eating.

Dr. Weiner says that its human nature to judge ourselves favorably, dismissing or underestimating our bad decisions and emphasizing our good ones.

Translation? Youre likely to pat yourself on the back for eating a salad on Tuesday, while overlooking the fact that you ate two bowls of B&J for dessert (and then still wonder why youre not losing weight). Tracking your caloric intake in a visible, tangible waylike in a food journal or on an app can help keep you accountable, and help you eliminate the bias we all have toward ourselves, says Dr. Weiner.

4. Youre not eating enough plant-based protein.

Generally speaking, protein has benefits: it fills you up (which means youll eat less food over time) and also helps you build muscle, skin, and healthy bones . But when it comes to weight loss, not all protein is created equal. Dr. Weiner warns about over-consuming animal proteinand the fat that typically comes with itbecause too much can lead to weight gain, and other health problems like diabetes.

Plant-based protein, on the other hand, is different (think: legumes, nuts, seeds, and whole grains). Dr. Weiner says you can eat higher amounts of these foods without worrying about negative effects on your health. Ive literally never seen a study suggesting that [sources of plant protein like nuts] cause weight gain, he adds.

5. Youre not looking at the big picture.

Frustrated because youve been on your diet for three months and youve only lost, like, eight pounds? Before you freak out and try some new fad diet, think about whether your goal is just to lose as much weight as possible right this second, or to slim down healthfully over time, so you can keep the weight off permanently.

We tend to look at weight loss in the short-term, when its actually a long-term problem, says Dr. Weiner. There will be individual ups and downs every day, just like there are in the stock market.

Instead of taking a short-term POV on weight loss, consider looking at how your weight has changed over the last several years and how you would like to feel several years from now, too.

6. Youre not eating whole foods.

If youre blowing off diets focused on eating whole, clean foods (think: the Mediterranean diet) you might want to reconsider. Nutrition experts have known for a long time that diets full of whole foods, like fruits, vegetables, grains, and protein, are associated with better weight-loss results than diets packed with processed foods (like cereal, crackers, and prepackaged meals).

A 2019 study in Cell Metabolism further emphasized the benefits of a whole food diet; when participants ate diets similar in nutrients (e.g., similar amounts of protein, fat, sugar, and fiber), the group consuming processed foods showed higher levels of caloric intake and weight gain than the group consuming whole foods.

7. Youre eating too many healthy foods.

Yes, sometimes too much of a good thing can be not so good. Just because you swapped your nightly bowl of ice cream for Greek yogurt doesnt mean you can eat twice as much. The basic rule of " fewer calories in, more calories out " still applies, even when what youre eating is healthy.

The one exception? Dr. Weiner says you really cant overeat vegetables (seriously, the more you eat, the better). If you ate a pound of them every day, you would still lose weight because it would change your other eating behaviors, he explains, referring to the fact that if you filled up on veggies, you would reduce your appetite for other less healthy foods.

8. Your cardio isnt intense enough.

Remember the info about quality and quantity of calories above? The same applies to exercise, says Dr. Weiner, who suggests focusing on intensity versus duration when youre trying to lose weight by incorporating exercise.

If you want to walk for weight loss, you would have to walk 10 to 12 miles per day, he explains. Walking one or two miles, like so many people do, is good for you in a million waysbut weight loss isnt one of them.

Instead, if you want your exercise to yield weight loss, you could benefit from choosing activities that will boost your heart rate like boot camps, cycling classes, CrossFit sessions, or other high-intensity workouts that maximize cardio.

9. Youre drinking sugary beverages.

Gonna hit you with something totally shocking here: If youre drinking even one soda per day, you will never lose weight, says Dr. Weiner. Ummm, back up for a sec...is soda really that bad for you? Sorry, but yes: Dr. Weiner says when you drink sugar it drives up weight gain far more than when you eat it.

If youre hungry and eat a cookie you will be less hungry, or youll eat less at lunch; but when you drink 150 calories it doesnt impact your hunger at all, he explains. So you drink a soda, then you still eat a normal lunch, and all youve done is add 150 calories to your daily intake (versus splurging on a cookie and naturally course-correcting by eating 150 calories less later on).

10. Youre not sleeping well .

Dr. Weiner also says working the night shift puts you at a major disadvantage. The disruption to your circadian rhythm, he explains, can lead to weight gainand switching back and forth between night and day shifts, like many people do in order to spend more time with family, is the worst of all. Its just nonstop disruption to an otherwise healthy, normal sleep-wake pattern.

For example, a 2019 study in the International Journal of Obesity observed weight loss over the course of 12 months in nearly 2,000 participants and found that those with less variability in sleep patterns were more likely to be more successful in their weight loss efforts.

Of course, not everyone has the luxury of choosing their work schedule or having a flexible boss. But if you are able to tweak your work schedule or work with your manager to avoid this, you should.

11. You work at a desk job.

Never underestimate the power of keeping your body moving regularly throughout the day. Overly sedentary lifestyles make it harder to lose weight, says Dr. Weiner. If you wake up every morning and then sit at a desk for work, then come home and sit on the couch to watch TV, [weight loss] won't happen.

12. Youre eating too often.

There was a time when eating frequent, small portions of food throughout the day was promoted as a way to lose weight, but science is beginning to show that the whole concept behind intermittent fasting might lead to better results. Dr. Weiner agrees, saying that getting the right amount of calories in a short period of time followed by a longer period of time where you get little to no calories can be more beneficial to your health than eating all day long (even if its small, healthy meals or snacks).

You should talk to your doctor or a nutritionist before trying an intermittent fasting diet, this way they can help you figure out a schedule that makes sense for you. There are also some groups of people for which intermittent fasting is not recommended, like anyone with blood-sugar regulation issues (e.g., diabetes) and pregnant people.

13. Youre not drinking enough water.

Can drinking water really help with weight loss, or is that just an urban legend? Its for real: A 2014 review of studies published in the Journal of the Academy of Nutrition and Dietetics found several links between water consumption and weight-loss results.

Basically? Yeah, you should be drinking more water.

14. Youre drinking too much alcohol.

Not to be a killjoy, but your bi-weekly happy hour could also be interfering with your goals. Alcohol is connected to weight gain for a few reasons: For one, it contains empty calories (which can grow astronomically high when you start drinking cocktails), and two, it changes your relationship to food.

People typically eat more when they drink because their appetite is increased and they stop paying close attention to calorie consumption. Drinking alcohol may also negatively change the way your body burns fat .

15. You have a medical condition that makes it harder.

Any medical condition that affects your hormones (like hypothyroidism or polycystic ovary syndrome), your insulin levels (like diabetes), or your blood pressure (like heart disease) will make it more difficult to lose weight.

Dr. Weiner adds that any injury which results in limited mobility can also contribute to weight gain, partly because it can lead to muscle lossand less muscle means you are burning less when your body is at restand partly because it will reduce your ability to exercise regularly.

16. Youre getting older.

All the diet and exercise in the world wont cancel out the fact that its just plain harder to lose weight the older you are. In your 20s, you might be able to cut back on booze and cake for a few weeks when you want to lose five pounds, but in your 40s, its gonna take more effort.

Focus on resistance training to build muscle mass, which can ultimately help you burn more at rest, and in turn, jumpstart your weight loss if you're stuck.

17. Youre stressed or depressed.

Major life changes, like divorce or a death in the family, are often a trigger for weight gain. Stress-eating is a real thing , and when youre depressed youre typically not focused on counting calories or exercising (because it takes so much effort just to make it through the day).

Weiner recommends finding holistic ways to manage your stress, even if its simply low-impact cardio. And of course, if youre feeling depressed, dont hesitate to get help from a mental health provider .

18. You have unresolved trauma.

While this is heavy stuff, it's important to be aware of the correlation between abuse and weight gain. A history of sexual abuse is often linked to weight gain , in particular, and the number of people who have been sexually abused, especially at young ages, is staggering: According to the National Sexual Violence Resource Center, one in three American women report experiencing some kind of sexual violence in their lifetime.

Whether youre a child or an adult (and whether or not your history is affecting your weight), there are resources that can help victims of sexual violence or other abuse.

19. Youre taking certain medications.

A possibly hidden reason why youre struggling to lose weight: Youre on a medication that can cause weight gain as a side effect. This includes diabetes medications, antidepressants, and steroid medications, among others .

Dr. Weiner suggests talking to your physician about your medications; sometimes they can be adjusted to make weight loss more possible.

20. You're struggling with food addiction.

If you find yourself desperately craving food at all costsand its sabotaging your diet and exercise effortsyou could be dealing with a food addiction . This doesnt mean youre not motivated or strong enough to defeat your cravings and lose weight; you may have developed an emotional reliance on food.

If you are prone to binging or gorging, focus nonstop on food, have trouble functioning in your job or personal life, or suffer from anxiety, depression, or insomnia, reach out to a health-care provider ASAP to be evaluated for food addiction. Its a type of eating disorder, and there is help available .

The bottom line: Clearly, there are a ton of reasons you might be struggling to lose weight, even if you are dieting and exercising more. If you feel you're dealing with any of the issues above, it's worth talking to your doctor, a therapist, or a dietitian to get help so you can reach a weight you feel comfortable and healthy at.