Why am I not losing weight? 12 reasons (+ how to fix them)

If you’ve been asking yourself, “Why am I not losing weight?” even though you’re eating healthy and working out, there may be a reason the scale isn’t moving. A weight loss plateau can happen for many reasons, from hidden calories and hormones to medical reasons for not losing weight that are easy to miss.

Here are the most common reasons you might have difficulty losing weight:

1. Not in a calorie deficit

2. Underestimating food intake

3. Overestimating calories burned

4. Gaining muscle while losing fat

5. Inconsistent tracking

6. Eating back exercise calories

7. Hormonal imbalances

8. Poor sleep

9. Too many liquid calories

10. Metabolic adaptation

11. Underlying medical conditions

12. Unrealistic expectations

Let’s discuss them and help you break out of a weight loss plateau.

This isn’t a comprehensive list, but these are some of the most common factors that can hinder results or make weight loss feel more challenging than it should.

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1. You're not actually in a calorie deficit

Weight loss occurs when you burn more energy than you eat. Sounds easy enough, but maintaining that deficit over time is where most people struggle.

The standard recommendation is to reduce your daily calorie intake by 500-750 calories below your maintenance level, which can lead to sustainable weight loss. But here's what most people don't realize: your body has regulatory mechanisms that adjust your food intake and energy expenditure over time.

Research on individuals ranging from Tour de France cyclists to military trainees reveals a consistent pattern: if you eat less on one day, your body doesn't immediately compensate; however, after several days, it prompts you to eat more to balance out the deficit.

So, what may have started as a deficit last month might not be one anymore if you aren’t paying close attention. This is why many people hit plateaus even when they feel like they're doing everything right.

2. You're underestimating how much you eat

Even for people who are paying attention to how much they eat, it’s still easy to get the numbers wrong.

In one study of 130 people with type 2 diabetes who had all received professional nutrition education, nearly half still underestimated the caloric deficit needed to reach their weight loss goal by more than 100,000 calories. When asked to calculate how many calories they'd need to cut, estimates varied widely, with most people guessing far lower than the actual number.

Cooking oils, condiments, handful-sized snacks, and restaurant meals all add up in ways that are easy to miss. If weight loss has stalled, taking a week or two to weigh, measure and track everything you eat might reveal gaps you didn't know existed.

3. You're overestimating calories burned during exercise

That intense workout probably burned fewer calories than you think. Research shows people often struggle to accurately estimate exercise calorie burn, and the errors can go in both directions. Some people underestimate by hundreds of calories, others overestimate by even more.

In one study, adults who walked or jogged on a treadmill for 25 minutes were asked to guess how many calories they’d burned and then prepare a meal they believed was equivalent.

After vigorous exercise, overweight adults not trying to lose weight overestimated their calorie burn by 72%, and then overestimated the calories in their meal by 37%.

That means a person who burned 300 calories might believe they burned over 500, a difference which can be meaningful when it comes to weight loss. If you’ve been “earning” extra snacks or meals based on your estimates, that might be stalling your progress.

4. You're building muscle while losing fat

If you’ve added strength training or resistance workouts, your body composition may be changing even if your weight isn’t. That’s because muscle tissue is denser than fat and takes up less volume, so your body can look leaner while the scale remains stable. 

Increasing lean muscle helps improve glucose metabolism and may play a role in regulating appetite and energy balance.

Pro tip: Tracking progress with body measurements or progress photos can show improvements that the scale can’t.

5. You're not tracking consistently

It’s easy to start strong with tracking, then slowly drift off. Maybe you log every meal for a few weeks until work gets hectic or you go on vacation. Most people don’t realize how quickly that drop-off happens.

Research comparing different mobile tracking methods, such as calorie-tracking apps, photo-based meal apps, and wearable devices, found that fewer than half of participants were still logging meals by week 10.

If you’ve stopped seeing results, try a short one-week “reboot” of daily tracking. It can help you notice small changes, like bigger portions or extra snacks, that might be slowing your progress.

6. You're eating back all your exercise calories

Sometimes, people eat more or choose higher-calorie foods after exercise, especially if the session felt intense or like hard work. Other times, it’s simply about refueling and satisfying post-workout hunger.

But the research on this is mixed. There’s limited evidence on how frequently people compensate for exercise by eating more, which foods they choose, or what drives those behaviors.The key isn’t to ignore hunger after working out but to stay aware of how your mindset can influence post-exercise food choices.

7. Your hormones may be working against you

Certain hormones play a direct role in how your body manages energy, and when they’re out of balance, losing weight can be harder.

Cortisol, the body’s “stress hormone,” affects metabolism and inflammation. In a six-month study of over 300 adults, people with higher cortisol, insulin, and stress levels were more likely to gain weight. In short, stress and hormonal shifts can make it easier to gain weight.

Thyroid hormones (T3 and T4) also influence metabolism. Too little, as in hypothyroidism, is linked to decreased insulin sensitivity and a slower metabolism and has been associated with weight gain. Too much thyroid hormone, as seen in hyperthyroidism, can cause insulin resistance in the liver and skeletal muscle and disrupt blood sugar control. 

If you’ve been following a consistent eating and exercise routine but still struggle with unexplained weight changes, it may be worth asking your healthcare provider about checking thyroid levels to rule out a hormonal cause.

8. You're not getting enough sleep

Poor sleep can interfere with weight loss in ways you might not expect. Research reviewing sleep deprivation studies found that sleep loss often leads to higher calorie intake, mainly from extra snacks and foods high in fat and carbohydrates. 

Lack of sleep also affects the hormones that regulate appetite, metabolism, and energy balance, making it harder to stay on track with healthy eating.

9. You're drinking too many calories

Liquid calories add up, often without you realizing. Studies show that when people consume sugar-sweetened beverages, such as soda, juice, or sweetened coffee, they don’t fully adjust their food intake to compensate for the extra calories they’re consuming.

Over time, that imbalance can lead to steady weight gain. If you’re trying to lose or manage weight, it helps to keep liquid calories in check. Swap sugary drinks for water, sparkling water, or unsweetened tea.

10. Your body has adapted to your routine

As you lose weight, your body starts using energy more efficiently, a process called metabolic adaptation. In a study of people following a low-calorie diet, those whose metabolism slowed the most took longer to reach their weight loss goals, even when sticking to their plan. 

This slowdown is your body’s way of conserving energy, which means you may need to adjust your calorie intake or activity level to keep making progress.

11. You may have an underlying medical condition

You can do a lot of things “right” and still struggle with weight if a health condition is involved. Secondary causes for obesity account for about 5–10% of cases and often relate to hormones and how the body regulates appetite, energy use, and fat storage.

Examples include thyroid disorders, sex-hormone imbalances, cortisol excess, certain brain injuries that affect appetite control, and even rare fat-distribution disorders.

If your weight changes don’t match your habits, consider this: underlying medical conditions can contribute to weight gain and may require targeted treatment in addition to lifestyle changes.

12. Your weight loss expectations may be unrealistic

Healthy, sustainable weight loss takes time. Conventional calorie-restricted diets usually cut 500–750 calories a day, which leads to about 0.5 kg (1 lb) of weight loss per week in the early months. As your body adjusts, the rate naturally slows down.

This means that losing 2 kg (around 4-5 lbs) a month is already a strong, healthy pace. Expecting faster results can make progress feel discouraging, even when it’s on track.

Weight can also fluctuate across the week due to normal changes in food intake, exercise, hydration, and hormonal cycles. In the long run, consistency (not speed!) is what drives lasting results.

Remember, there’s no single reason you might hit a weight loss plateau, and everyone’s body responds differently, even when they’re eating less but not losing weight.

If you’re still eating carefully, exercising regularly, and yet progress stalls, what do you do then? Double-check your routine, then, if you’re still stuck, try adjusting by:

• Auditing your habits: Track your meals for a few days, measure portions again, or note snacks that have crept back in. It’s easy to underestimate small changes over time.

• Moving more in small ways: Walk while taking phone calls, park farther away, or tackle that closet you’ve been avoiding. Everyday movement can help you add to your calorie burn.

• Checking your recovery: Lack of sleep, chronic stress, or skipping rest days can make weight loss seem harder. Take a pause and give it time.

• Practicing patience: People don’t lose weight in a straight line. Sometimes, the scale stays steady while your body composition is changing in ways you can’t see.

A plateau isn’t a dead end; it can be a sign that what used to challenge you now feels easy. A few small shifts can help you find your footing again.

For some people, lifestyle changes alone aren’t enough to achieve or maintain meaningful weight loss. That’s where prescription medications such as GLP-1 receptor agonists, can help.

One of the best-studied options is semaglutide, available under brand names like Wegovy or Ozempic. These medications work by mimicking a natural hormone in the body (GLP-1) that helps regulate appetite, slow digestion (by slowing how quickly food leaves your stomach), and improve blood sugar control.

People who may benefit from medication support are typically those who:

• Have obesity or overweight with related medical conditions

• Have tried healthy eating and regular physical activity without achieving sufficient progress

• Need additional help managing blood sugar levels or reducing the risk of cardiovascular (heart) disease

These medications are always recommended to be used alongside a balanced diet and physical activity, not as a replacement for them. For some, these medications can make it easier to follow through on healthy habits by helping to reduce hunger and cravings.

If you’re thinking about trying a GLP-1 medication, start by talking with a licensed healthcare provider. They can help determine whether it’s safe and medically appropriate for your health and goals.

Weight changes, whether gain or loss, can be influenced by many factors. Sometimes the issue isn’t diet or willpower but underlying medical or hormonal causes. 

You should reach out to a healthcare professional if you’re still asking, “Why can’t I lose weight?” and notice things like:

• Unexplained weight gain or loss that doesn’t match your eating or activity levels

• Missing a menstrual period after significant weight loss (which can be linked to low estrogen levels and ovulation changes)

• Medications that may affect your weight, since some prescriptions can alter appetite and metabolism

A primary care clinician can run blood tests to check thyroid function, hormone levels, or nutrient deficiencies. From there, you might work with a nutritionist for meal planning or a psychologist if stress or emotional eating are making things harder.

In some cases, prescription weight loss medications or referrals to a specialist may be appropriate, something you can discuss further with your healthcare provider.

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Weight loss is complex, and progress rarely happens exactly as you expect. If your results have stalled and you’re wondering, “Why am I not losing weight?” it’s worth stepping back to reassess what’s changed.

• Small shifts matter: Changes in food intake, activity, or sleep can make a difference over time. Revisit your habits to see where small adjustments could help.

• Your body adapts: Metabolic adaptation is normal; it’s your body conserving energy as you lose weight. 

• Underlying health conditions play a part: Elevated cortisol and thyroid issues are just a few medical factors that can influence weight changes. Check in with a healthcare provider if you think your lifestyle doesn’t match your weight loss.

• Be patient with the process: Healthy, sustainable weight loss typically happens at a rate of 1-1.5 lbs per week. Expect fluctuations and focus on long-term consistency.

• Help is available: For some, medical guidance or prescription options like GLP-1 medications can support weight management when lifestyle changes alone aren’t enough.

The goal is steady, sustainable progress, especially if you’ve been working out but not losing weight. With realistic expectations and the right support, you can move past a plateau and keep making progress that lasts.