So, if it’s not a lack of willpower, what’s going on? The answer is often a complex combination of factors. Let’s break down the most common reasons you can’t lose weight no matter what you try. 

You’re Undereating (and Your Body Thinks It’s Starving) 

It sounds counterintuitive, but it’s a common trap. If you cut calories too drastically, your body’s ancient survival mechanisms perceive this as a famine. It responds by going into “energy conservation mode.” This triggers two things: 

• A Slower Metabolism – Your body lowers its basal metabolic rate (BMR), or the number of calories you burn at rest, to save energy. 

• Hormonal Havoc – Your body increases hunger hormones (like ghrelin) and decreases satiety hormones (like leptin), making you feel hungrier and less satisfied. Chronic undereating can directly disrupt this balance. 

Signs this might be you: Persistent fatigue, irritability, feeling cold, and stalled progress despite eating very little. 

You’re Eating Healthy Foods, But in Excess 

On the other end of the spectrum, it’s possible to overdo it on the “good stuff.” Foods like avocados, nuts, seeds, olive oil, and fruit-packed smoothies are incredibly nutritious, but they are also very calorie-dense. 

A “healthy diet but no weight change” often means you’re eating the right foods, just too much of them. Many people underestimate liquid calories (in smoothies, cooking oil, alcoholic drinks, or that splash of creamer), or forget to factor in the daily impact of frequent “healthy” snacking. The solution isn’t restriction; it’s becoming more mindful about portion control. 

Hormones and Insulin Resistance Are Working Against You 

This is one of the most significant and overlooked reasons for not losing weight. Hormones act as chemical messengers that control everything, including your metabolism. 

The most powerful of these is insulin, the hormone that manages blood sugar. When you eat, insulin’s job is to move sugar (glucose) from your blood into your cells for energy. But if your cells are constantly bombarded with glucose, they can become “numb” to insulin’s signal. 

This is insulin resistance. When this happens, your body struggles to use energy, promotes fat storage (especially in the abdomen), and leaves you feeling hungry again, even after a meal. Conditions like PCOS, thyroid issues, and perimenopause can make this hormonal imbalance and resulting weight gain even worse.  

When insulin resistance goes unchecked, it can lead to prediabetes, a condition where blood sugar levels are elevated but not yet high enough for a diabetes diagnosis. According to CDC estimates, up to 98 million U.S. adults have prediabetes, and more than 80% don’t know it.  This means millions of people are struggling to lose weight without realizing that their metabolism is working against them.   

Medication Side Effects 

Sometimes, the obstacle to weight loss is in your medicine cabinet. Certain prescription medications are necessary for your health but can cause fluid retention, increase your appetite, or slow your metabolism as a side effect. Common examples include: 

• Antidepressants (SSRIs, SNRIs) 

• Beta-blockers 

• Steroids (like prednisone) 

• Antihistamines 

If you suspect your medication is contributing, never stop taking it. Instead, have a conversation with your doctor about your concerns. 

Stress Keeps You Stuck in “Storage Mode” 

We live in a high-stress world, and it’s taking a toll on our bodies. Chronic stress—from work, family, or even over-exercising—floods your body with the stress hormone, cortisol. 

Elevated cortisol does two things that are terrible for weight loss: it increases your appetite (especially for sugar and fat) and it signals your body to retain fat, particularly around the midsection. 

Research shows that chronic stress and high cortisol can impair insulin sensitivity, leading to higher blood sugar and more fat storage. Even if your diet is perfect, a high-stress life can disrupt your sleep and blood sugar balance, effectively putting your metabolism in “storage mode.” 

Your Gut Health and Sleep Are Affecting Results 

The two things we often sacrifice first, sleep and rest, are non-negotiable for metabolic health.  

Poor sleep (less than 7-9 hours a night) directly alters your hunger hormones, ghrelin and leptin, making you feel hungrier and less satisfied. In fact, studies show people who consistently sleep less than 6 hours per night are 55% more likely to gain weight. 

Similarly, your gut microbiome, the trillions of bacteria in your digestive tract, plays a key role in digestion, inflammation, and hormone regulation. A diet lacking fiber or an imbalance in gut bacteria can interfere with your body’s ability to extract nutrients and manage weight. 

Chronic Inflammation 

Inflammation is your body’s natural response to injury or infection. But when inflammation becomes chronic and low-grade, it can wreak havoc on your metabolism. This persistent inflammation can come from autoimmune disorders, food sensitivities, poor gut health, or even chronic stress. 

When your body is in a state of inflammation, it prioritizes “healing” this perceived threat over burning fat. Studies also show that inflammation can reduce your body’s sensitivity to leptin, the “fullness” hormone, which can increase hunger and encourage fat storage.