Why Can’t I Lose Weight? Understanding Why Losing Weight Can Seem So Hard

If you’re struggling with weight loss and asking yourself, “Why am I not losing weight?”, you’re not alone. Many people wonder, “Why is it so hard to lose weight?” even when they feel they’re doing everything right.

Weight management is a complex process; it involves a combination of factors both within and outside your control. Everyone’s body and metabolism are different, meaning what works for one person might not work for another.

Healthcare professionals such as your GP or a registered dietitian can help you navigate this process and create a personalised plan.

Overly Restrictive Diets: A Common Reason You Can’t Lose Weight

It may sound counterintuitive, but sometimes the reason you’re not losing weight is that you’re not eating enough. Overly restrictive diets can cause something called metabolic adaptation, when your body lowers its calorie burn to conserve energy because it’s not getting enough fuel.

Your resting energy expenditure (REE), the number of calories your body burns at rest, typically makes up 60–70% of your daily energy needs. If your intake falls far below this, your metabolism slows, reducing your calorie deficit and stalling weight loss.

Example:
Someone with a total energy expenditure of 2100 calories starts eating 1200 per day. Initially, they lose weight, but soon the scale stops moving, and eventually, weight creeps back. Their REE may have dropped from 1600 to 1000 calories due to restriction. To recover, they’d need to slowly increase calories to restore metabolism before re-establishing a modest deficit.

Even if your calories aren’t drastically low, overly strict diet rules, like cutting out food groups or eating at rigid times, can make your plan unsustainable. Instead of quick fixes, focus on long-term lifestyle changes:

• Eat a variety of nutrient-dense foods

• Include regular physical activity you enjoy

• Manage stress

• Build habits you can maintain long-term

There’s no safe way to lose weight fast; slow, steady, and sustainable progress is what supports both your weight and your overall health.

Diet Quality: Why the Type of Calories Matters for Weight Loss Struggles

If you’re working out but not losing weight, it might not just be about calories; it’s also about what those calories are made of.

Your body uses energy to digest and metabolize food, known as the thermic effect of food. This makes up around 10% of your daily energy expenditure:

• Protein: 20–30% of calories burned during digestion

• Carbohydrates: 5–10%

• Fat: 0–3%

Because protein takes more energy to process, including it in meals supports satiety and metabolism. A balanced diet with all three macronutrients, carbs, fat, and protein, helps manage blood sugar, reduce cravings, and keep you feeling full.

A balanced plate with variety ensures your body gets essential vitamins, minerals, and phytonutrients, all vital for overall health and effective, sustainable weight management.

Chronic Conditions: Medical Reasons Why You Might Struggle to Lose Weight

Sometimes the answer to “Why can’t I lose weight?” lies in underlying health conditions.
Common examples include:

• Insulin resistance (such as with PCOS)

• Thyroid disorders like hypothyroidism

These can affect metabolism and body composition. Certain medications, such as steroids (e.g., prednisone) or psychiatric medications (e.g., lithium), may also cause weight gain.

If you suspect this applies to you, talk to your doctor about checking for underlying conditions or referring you to a registered dietitian.

Even with medical factors, the basics remain important: consistent physical activity, cutting back on sugary drinks, and eating nutrient-dense, whole foods.

Age and Metabolism: Why Losing Weight Gets Harder Over Time

Another reason you might be struggling with weight loss as you get older is that metabolism naturally slows with age, largely due to loss of lean muscle mass, typically about 1% per year from middle age.

The solution? Strength training.

Lifting weights helps maintain muscle mass and bone density, which not only supports metabolism but also reduces the risk of osteoporosis and fractures later in life.

Stress: How Stress Makes Losing Weight So Hard

If you’re exercising but not losing weight, stress might be the hidden culprit.

Chronic stress raises cortisol levels, disrupting hormones that regulate appetite (like ghrelin, leptin, and insulin). It can also trigger emotional eating and cravings for high-calorie “comfort” foods.

While you can’t eliminate all stress, you can manage it through healthy habits such as yoga, meditation, therapy, dancing, or spending time in nature. Managing stress supports both weight control and heart health.

Sleep and Weight: Why Sleep Impacts Your Weight Loss Struggle

Poor sleep can sabotage your weight loss progress. Lack of rest alters leptin and ghrelin, hormones that control hunger and fullness, making you feel hungrier and less satisfied after meals.

Shift workers or those with circadian rhythm disruptions often experience both stress and sleep misalignment, which can impact metabolism and weight regulation. Prioritising consistent, quality sleep supports better appetite control and energy balance.

Alcohol and Weight Loss: Reassessing Empty Calories

If you’re asking, “How can I get started losing weight?”, one simple change is to look at your alcohol intake.

Alcohol provides 7 calories per gram, almost as many as fat, but with no nutritional value. Cutting back can significantly help your calorie deficit.

Here’s a quick look at the calorie content of common drinks:

• 12oz beer: ~150 calories

• 5oz wine: ~125 calories

• Vodka cranberry: ~150 calories

According to the World Health Organization, no level of alcohol is considered safe, and drinking less is always better than drinking more. If you do drink, moderation is key: up to two drinks per day for men, one for women.

Genetics and Set Point: When You’re Doing Everything Right but Still Can’t Lose Weight

Sometimes, “Why can’t I lose weight?” has to do with genetics.
Your genes influence how your body uses energy and stores fat, factors that aren’t entirely in your control.

The set point theory suggests that each person’s body naturally gravitates toward a certain weight range, defended by metabolic and hormonal mechanisms. That’s why two people can eat similarly and exercise equally yet weigh differently.

The takeaway: focus on healthy habits, not perfection. The “healthy weight” for you may look different from someone else’s, even with the same lifestyle.

TL;DR — Why Losing Weight Can Be So Hard

If you’ve been thinking, “I can’t lose weight no matter what I do”, remember that weight loss is multifactorial. Diet, exercise, sleep, stress, genetics, age, and even alcohol all play roles.

Sustainable weight loss comes from small, steady lifestyle changes, not restrictions or extremes. Stay consistent, focus on balance, and seek professional guidance if needed.