Why Can’t I Lose Weight Even Though I Diet and Exercise? Hormones, Metabolism & Weight-Loss Plateaus

Quick Answer: Why Can’t I Lose Weight Even Though I Diet and Exercise?

There may not be one single reason.

Common contributors can include:

Metabolic adaptation after weight loss
Increased hunger as body weight decreases
Reduced spontaneous daily movement
Changes in lean muscle mass
Menopause-related body-composition changes
Thyroid disease
Certain medications
Sleep problems
Stress
Underlying metabolic disease
Changes in food intake that are difficult to recognize
Hormonal disorders in selected patients

Research confirms that the body adapts during weight loss.

As weight decreases, total energy expenditure generally falls. Some people also experience adaptive thermogenesis, meaning measured energy expenditure drops somewhat more than would be expected from the change in body size alone. A 2024 human study measured an average adaptive reduction in resting energy expenditure of approximately 121 calories per day after substantial weight loss, although individual responses varied widely.

A 2026 review of weight-loss plateaus similarly concluded that reduced energy expenditure, increased appetite, and reductions in non-exercise activity can all contribute to the point where weight loss slows or stops.

That does not mean your metabolism is permanently broken.

It means the human body actively responds to changes in energy intake and body weight.

Watch: Amanda Brandao, RN, Explains Why Weight Loss Can Become Difficult

Video Transcript

Amanda Brandao, RN:

I’m a nurse, and I’m going to tell you the real reason why you can’t lose weight no matter what you’re trying.

First, your hormones are working against you.

If your testosterone level is low and your cortisol levels are chronically elevated, then you’re likely storing fat around your midsection.

It doesn’t matter how clean you eat or how often you go to the gym, your metabolism has slowed down.

Second, your metabolism has adapted to fight you.

Years of calorie restriction, crash diets, and over-exercising have taught your body how to do more with less.

Third, your body needs clinical support, not just more effort.

There’s a point where lifestyle changes just aren’t enough.

Most people hit that wall and instead of looking for a solution, they blame themselves.

Important Context About the Video

Amanda highlights three legitimate areas worth investigating:

hormones, metabolic adaptation, and the potential role of medical weight-management support.

But there are a few important nuances.

Hormones can influence body composition, but they are not always the reason weight loss is difficult.

Conditions involving thyroid hormone, pathologically elevated cortisol, menopause-related hormonal changes, and testosterone deficiency can affect metabolism or body composition.

However, most people struggling to lose weight do not simply have one hormone that needs to be “balanced.”

Cortisol and belly fat have a relationship, but it is complicated.

Long-term exposure to excess cortisol, as occurs in Cushing syndrome, clearly promotes central adiposity and metabolic dysfunction. Research also links cortisol metabolism with visceral obesity.

But studies examining ordinary stress-related cortisol activity and obesity have produced inconsistent results. A systematic review found significant variation between studies and concluded that the relationship between obesity and HPA-axis activity remains complex.

So having abdominal fat does not automatically mean your cortisol is “too high.”

Low testosterone and excess weight can affect each other.

In men, obesity itself can contribute to lower testosterone.

The Endocrine Society’s July 2026 statement specifically notes that when low testosterone is associated with overweight or obesity and there is no other identified pathological cause, weight loss is typically the first-line approach, rather than automatically beginning testosterone therapy.

Metabolic adaptation is real, but your metabolism is not permanently ruined.

The body reduces energy expenditure as weight is lost, and additional adaptive changes may occur.

Those responses make continued weight loss harder.

They do not mean previous dieting has permanently destroyed your ability to lose weight.

1. Weight Regulation Is More Than Willpower

Body weight is influenced by the balance between energy intake and energy expenditure.

But both sides of that equation are biologically regulated.

Your brain receives signals involving:

Hunger
Fullness
Food reward
Stored energy
Gastrointestinal hormones
Adipose tissue
Sleep
Stress
Physical activity

When weight decreases, the body may respond in ways that make additional loss harder.

NIDDK describes the weight-reduced state as involving physiological adaptations that can both reduce energy expenditure and increase the drive to eat.

That is one reason a calorie deficit that produced consistent weight loss six months ago may no longer produce the same rate of change today.

2. Can Hormones Make Weight Loss Harder?

Yes, in some patients.

But “hormone imbalance” is a broad phrase.

Hormones that may be relevant to body weight or composition include:

Thyroid hormones
Cortisol
Testosterone
Estrogen
Insulin
Reproductive hormones
Appetite-regulating hormones

The presence of stubborn weight alone does not diagnose a hormone disorder.

A medical evaluation should look at the patient’s overall symptom pattern, medical history, medications, age, reproductive stage, and other clinical findings before deciding which laboratory tests make sense.

The Re/ Clinic currently offers both hormone-balance services and medical weight-management services, which makes these overlapping concerns reasonable to evaluate together when clinically appropriate.

3. Cortisol and Abdominal Fat

Cortisol is essential.

It helps regulate:

Metabolism
Blood pressure
Immune responses
Stress responses
Glucose availability

The problem occurs when the body is exposed to excessive glucocorticoid activity for prolonged periods.

Cushing syndrome provides the clearest human example.

People with chronic pathological cortisol excess commonly develop:

Central fat accumulation
Insulin resistance
Muscle changes
Metabolic complications

Recent research continues to describe excessive cortisol exposure as a contributor to visceral obesity and metabolic syndrome.

But everyday stress is not the same as Cushing syndrome.

Researchers studying obesity and normal-range cortisol activity have found inconsistent patterns. Some people with abdominal obesity demonstrate altered HPA-axis responses, while others do not.

So if someone says:

“You have belly fat, therefore your cortisol is high.”

that is not enough information to make a diagnosis.

4. Should Everyone Struggling With Weight Test Cortisol?

No.

Cortisol testing is most useful when a clinician has a specific reason to suspect abnormal cortisol physiology.

Testing cortisol without a clinical question can be difficult to interpret because cortisol naturally changes based on:

Time of day
Sleep
Acute stress
Illness
Medications
Testing method

If symptoms or physical findings raise concern for pathological cortisol excess, an appropriate endocrine evaluation is very different from assuming everyday stress is preventing weight loss.

5. Testosterone and Body Composition

Testosterone plays a role in:

Muscle mass
Fat distribution
Bone health
Sexual function
Other physiological processes

Men with true hypogonadism may experience changes in body composition.

But low testosterone and obesity have a particularly complicated relationship.

Excess adiposity can itself contribute to lower testosterone concentrations.

That is why the Endocrine Society cautions against diagnosing testosterone deficiency based on nonspecific symptoms alone and emphasizes addressing reversible causes, including obesity and certain medications.

For men with obesity-associated low testosterone and no other pathological cause, weight reduction may improve testosterone without automatically requiring TRT.

So the relationship is not simply:

Low testosterone causes belly fat.

It can also involve:

Greater adiposity contributing to lower testosterone.

6. What About Testosterone in Women?

Women also produce testosterone, but female weight regulation should not be reduced to a single testosterone value either.

Changes in estrogen and other reproductive hormones during perimenopause and menopause are better studied in relation to midlife body-composition changes.

Hormone testing and treatment should therefore be individualized rather than assuming that every woman with stubborn weight needs testosterone.

7. Thyroid Hormones and Weight

The thyroid deserves a place in any discussion about unexplained weight changes.

Hypothyroidism can reduce metabolic rate and contribute to some weight gain.

However, the American Thyroid Association notes that thyroid-related weight gain is typically more modest than many patients expect, with much of the additional weight resulting from salt and water retention rather than large amounts of new body fat.

For many patients, roughly 5 to 10 pounds may be attributable to hypothyroidism, depending on severity.

Once hypothyroidism is appropriately treated and thyroid levels normalize, the ability to gain or lose weight generally resembles that of people without thyroid disease.

So:

“I can’t lose weight, therefore it must be my thyroid”

is not always accurate.

But unexplained weight change combined with symptoms such as fatigue, cold intolerance, constipation, dry skin, or other thyroid-related concerns may justify evaluation.

8. Perimenopause, Menopause, and Changing Body Composition

Many women notice their bodies changing during midlife even when the number on the scale has not changed dramatically.

This observation has real biological support.

A 2025 review concluded that menopause is associated with changes involving:

Reduced muscle mass and strength
Increased fat mass
Greater visceral fat accumulation

But the researchers also emphasized that the exact contributions of hormonal change, aging, energy balance, and lifestyle remain difficult to separate.

Other menopause research similarly shows that the hormonal transition is associated with a shift toward greater abdominal fat, even when menopause alone does not explain all midlife weight gain.

That may explain why someone can say:

“My weight hasn’t changed much, but my waist definitely has.”

Body composition and scale weight are not the same measurement.

9. What Is Metabolic Adaptation?

This is the section of Amanda’s video with some of the strongest scientific support.

When you lose weight, your body becomes smaller.

A smaller body generally requires less energy.

So some reduction in calorie expenditure is expected.

But researchers have also identified adaptive thermogenesis, where energy expenditure may fall somewhat more than predicted based solely on changes in body size and composition.

In a 2024 study involving people with severe obesity who lost approximately 18 kilograms over 10 weeks, measured resting energy expenditure was an average of 121 calories per day below predicted values. Individual responses varied significantly.

That may not sound enormous.

But combine it with:

Increased hunger
Smaller energy requirements
Reduced spontaneous movement
Less body mass to move around
Greater food preoccupation

and continued weight loss becomes harder.

10. Can Years of Dieting Damage Your Metabolism?

“Damage” is probably the wrong word.

A better term is:

adaptation.

The body is designed to respond to reduced energy availability.

NIDDK specifically recognizes metabolic adaptation and increased appetite as physiological challenges after weight reduction.

A 2026 review of weight-loss plateaus found that total energy expenditure decreases during weight loss, while hunger may increase. It identified reductions in non-exercise activity thermogenesis, or NEAT, as an especially important contributor.

NEAT includes all of the movement you do that is not formal exercise:

Standing
Walking around your home
Fidgeting
Taking stairs
Moving while working
Everyday physical tasks

Someone can continue exercising at the gym while unconsciously moving less during the rest of the day.

That makes metabolic adaptation particularly difficult to notice.

11. What About Crash Dieting?

Very restrictive diets can produce rapid weight loss.

But rapid loss is not always synonymous with sustainable fat loss.

Greater restriction can increase:

Hunger
Dietary fatigue
Food preoccupation
Difficulty maintaining adherence

Weight loss itself can also reduce both resting and non-resting energy expenditure.

That does not mean everyone who has ever crash dieted has permanently damaged their metabolism.

It means repeated cycles of aggressive restriction can create a difficult pattern in which maintaining another very large deficit becomes increasingly challenging.

12. Why Do Weight-Loss Plateaus Happen?

A plateau means the amount of energy being consumed and the amount being expended have reached a new balance.

That can happen even when the same plan produced weight loss earlier.

A 2026 review reported that plateaus commonly emerge after several months of weight-loss treatment, although timing varies widely. Contributors can include:

Lower total energy expenditure
Reduced NEAT
Increased appetite
Previous weight-loss history
Behavioral changes
Genetic differences

The plateau is therefore not necessarily evidence that:

“Nothing works for me.”

It may mean the treatment plan needs reassessment.

13. Other Reasons Weight Loss May Be Difficult

Hormones and metabolism are not the only possibilities.

Medications

A number of medication classes can contribute to weight gain or metabolic changes.

A 2024 review identified examples including:

Some antipsychotics
Certain antidepressants
Glucocorticoids
Some beta blockers
Insulin
Certain neuropathic medications
Some sleep medications
Other drugs

Psychiatric medications deserve especially individualized discussion because weight-gain liability varies considerably between specific drugs.

Never stop a prescribed medication solely because of weight concerns without discussing alternatives with the prescribing clinician.

Sleep

Insufficient or disrupted sleep may affect appetite, energy, and the ability to consistently maintain weight-management behaviors.

It can also signal conditions such as obstructive sleep apnea, which is common in people with obesity.

Loss of Muscle Mass

Muscle is metabolically active tissue.

A weight-loss strategy that produces substantial lean-mass loss can affect body composition and energy requirements.

This is one reason resistance training and adequate nutrition are important components of many weight-management plans.

Changes in Food Intake

Human beings are not calorie-tracking machines.

Portion size, liquid calories, restaurant meals, bites and snacks, weekends, and changes in food density can all affect total intake without being obvious.

That does not mean the answer is always:

“You’re secretly eating too much.”

It means food intake is one variable worth reviewing alongside all the others.

14. When Lifestyle Changes May Not Be Enough

This is Amanda’s third point, and it aligns with major medical guidance.

Lifestyle intervention remains a foundational component of weight management.

But lifestyle is not the only evidence-based treatment for obesity.

NIDDK states that when lifestyle changes alone are insufficient, additional treatments may include prescription medications or metabolic and bariatric surgery.

A 2025 clinical practice guideline similarly describes obesity pharmacotherapy as an integral component of comprehensive obesity management for appropriate patients, alongside health-behavior changes and bariatric treatment when indicated.

That means needing medical support does not indicate that diet and exercise “failed.”

It means different tools may be appropriate at different stages of a chronic disease.

15. What Does “Clinical Support” Actually Mean?

Clinical support should mean more than simply handing someone a weight-loss prescription.

A thoughtful weight-management evaluation may consider:

Weight history
Previous diets and medications
Current nutrition
Physical activity
Resistance training
Sleep
Stress
Medical conditions
Medication-related weight effects
Menstrual or menopausal changes
Symptoms of hormone disorders
Thyroid status when clinically indicated
Cardiometabolic risk factors
Patient goals
Previous response to treatment

The treatment plan might involve:

Nutrition changes
Exercise programming
Resistance training
Sleep improvement
Medication review
Treatment of an underlying endocrine condition
FDA-approved weight-management medication for an eligible patient
Referral to another specialist
Bariatric treatment when appropriate

There is no one treatment that makes sense for every person struggling with weight.

16. What About Semaglutide and Tirzepatide?

Medications in the GLP-1 and GIP/GLP-1 classes have significantly expanded medical options for chronic weight management.

FDA-approved chronic weight-management medications currently include semaglutide under the Wegovy brand and tirzepatide under the Zepbound brand for patients who meet their respective indications.

These medications influence appetite and satiety pathways.

They do not eliminate the role of nutrition, activity, sleep, body composition, or long-term weight-maintenance planning.

NIDDK states that weight-management medications work best as part of a broader lifestyle program.

The Re/ Clinic currently offers semaglutide- and tirzepatide-based weight-management services in Sandy, Utah.

Patients should discuss the specific product being prescribed, whether it is an FDA-approved branded medication or a compounded formulation, its indication, risks, and ongoing monitoring with their provider.

17. Who Might Benefit From Weight-Management Medication?

Eligibility depends on the medication and the patient’s health.

In general, NIDDK notes that prescription weight-management medication may be considered for adults with:

BMI of 30 or greater, or
BMI of 27 or greater with a weight-related health condition

although the final decision should be individualized.

BMI is also not the only consideration.

Newer obesity guidance increasingly emphasizes evaluating central adiposity and obesity-related health complications alongside BMI when making treatment decisions.

Medication should be selected based on factors such as:

Medical history
Other medications
Potential benefits
Risks and side effects
Weight-related conditions
Treatment goals
Cost and access

18. What Should a Weight-Loss Evaluation Include?

At The Re/ Clinic, a patient struggling with weight may benefit from looking at the full picture rather than assuming the answer is simply another diet.

An evaluation may include discussion of:

Your Weight History

When did weight become difficult to manage?

Was there a specific change?

Previous Attempts

What have you tried?

What worked temporarily?

What did not?

Hormonal Symptoms

Depending on the patient, relevant symptoms may include:

Menstrual changes
Menopause symptoms
Sexual changes
Unexplained fatigue
Thyroid-related symptoms
Other endocrine concerns

The Re/ Clinic currently offers hormone evaluation alongside its medical weight-management services.

Medications

Could something you take be influencing weight or appetite?

Sleep

Are you sleeping enough?

Do you snore?

Do you wake rested?

Nutrition

Rather than asking only:

“Are you eating healthy?”

it may be more useful to look at:

Protein
Meal structure
Total intake
Hunger
Satiety
Alcohol
Liquid calories
Dietary sustainability

Body Composition

The scale cannot tell you whether changes involve:

Fat
Muscle
Water

Preserving lean mass becomes particularly important during significant weight loss.

Treatment Goals

The goal should not always be the lowest possible number on a scale.

Better goals may involve improvements in:

Metabolic health
Strength
Mobility
Sleep
Blood pressure
Glucose
Body composition
Quality of life

Frequently Asked Questions

Why can’t I lose weight even though I barely eat?

Several possibilities exist.

Energy expenditure decreases as body weight declines, and metabolic adaptation may make continued loss more difficult.

However, very low reported intake combined with no weight change can also warrant a closer review of food intake, medical history, medications, body composition, and possible underlying conditions.

Can your metabolism become too slow to lose weight?

Energy expenditure can decrease during and after weight loss.

Adaptive thermogenesis can also produce an additional decline beyond what would be expected from weight change alone.

That is different from saying metabolism is permanently “broken.”

Can crash dieting ruin your metabolism?

There is evidence that substantial calorie restriction and weight loss can trigger adaptive reductions in energy expenditure.

The effect varies between people and is better described as metabolic adaptation than permanent metabolic damage.

Can cortisol make you gain belly fat?

Pathological cortisol excess clearly promotes central fat accumulation.

Cortisol metabolism is also associated with visceral obesity.

But everyday cortisol patterns and obesity have a more complicated and inconsistent relationship.

Belly fat alone cannot diagnose high cortisol.

Does low testosterone cause belly fat?

Low testosterone can be associated with changes in body composition in men with true hypogonadism.

However, obesity can also lower testosterone.

For obesity-associated low testosterone without another pathological cause, the Endocrine Society currently recommends weight loss as the usual first-line approach.

Can menopause make it harder to lose weight?

Menopause is associated with changes in body composition, particularly greater visceral fat accumulation and reductions in lean mass.

Aging, energy balance, physical activity, sleep, and other factors also contribute.

Can hypothyroidism prevent weight loss?

Hypothyroidism can decrease metabolic rate and contribute to some weight gain.

However, thyroid-related weight gain is often more modest than patients expect, and much of it may reflect salt and water retention.

Once hypothyroidism is appropriately treated, persistent weight difficulty usually cannot be attributed solely to the thyroid.

Why did my weight loss suddenly stop?

You may have reached a new energy balance.

As weight decreases:

The body requires fewer calories
Energy expenditure falls
Hunger may increase
Daily spontaneous movement may decrease

These factors can contribute to a weight-loss plateau.

How long before a weight-loss plateau happens?

There is no fixed timeline.

A 2026 review found that plateaus frequently appear approximately six to eight months into weight-loss programs, but there is substantial individual variation.

Do I just need to eat less if I plateau?

Not necessarily.

Further restriction is one possible strategy, but it is not always the best one.

The plan may need to consider:

Protein intake
Resistance training
Daily movement
Hunger
Medication
Sleep
Treatment adherence
Current calorie needs
Medical contributors
Weight-management pharmacotherapy when appropriate

When should I consider weight-loss medication?

Prescription medication may be reasonable when lifestyle changes alone have not been sufficient and a patient meets appropriate medical criteria.

NIDDK notes that adults with BMI of at least 30, or at least 27 with certain weight-related health conditions, may be candidates depending on the medication and individual circumstances.

Do weight-loss medications replace diet and exercise?

No.

Evidence-based guidelines recommend medication alongside sustainable health-behavior changes rather than as a replacement for them.

Why do people regain weight after losing it?

Weight regain can be influenced by persistent biological adaptations involving appetite and energy expenditure as well as environmental and behavioral factors.

NIDDK recognizes weight-loss maintenance as one of the most difficult parts of obesity treatment because of these physiological adaptations.

If the Same Strategy Stopped Working, It May Be Time to Change the Strategy

Weight loss is often presented as an equation of discipline:

Eat less. Move more. Try harder.

Those behaviors matter.

But they are not the whole story.

Your body changes as you lose weight.

Your calorie needs change.

Your hunger signals may change.

Your movement may change.

Your hormones, medications, sleep, age, body composition, and health can all change too.

Sometimes the next step is adjusting nutrition or exercise.

Sometimes it is identifying an underlying medical issue.

And for appropriate patients, sometimes it is adding evidence-based medical treatment.

At The Re/ Clinic in Sandy, Utah, we offer medical weight-management services including semaglutide- and tirzepatide-based programs, along with hormone evaluation when clinically appropriate.

Schedule a weight-management consultation with The Re/ Clinic to discuss what may be contributing to your plateau and what options may be appropriate for you.

Call: 385-240-1000
Location: 9035 S 700 E, Sandy, UT 84070

References

National Institute of Diabetes and Digestive and Kidney Diseases. Treatment for Overweight & Obesity. Reviews lifestyle intervention, weight-management medications, and bariatric treatment as components of evidence-based obesity care.
National Institute of Diabetes and Digestive and Kidney Diseases. Prescription Medications to Treat Overweight & Obesity. Current information regarding medication eligibility, FDA-approved long-term weight-management drugs, lifestyle treatment, and long-term management.
Adaptive thermogenesis, at the level of resting energy expenditure, after diet alone or diet plus bariatric surgery. Obesity. 2024. Human study demonstrating measurable adaptive reductions in resting energy expenditure following substantial weight loss.
Weight Loss Plateau: Reasons, Challenges, and Solutions: A Narrative Review. Health Science Reports. 2026. Current review of metabolic adaptation, hunger, total energy expenditure, NEAT, and weight-loss plateaus.
National Institute of Diabetes and Digestive and Kidney Diseases. The Physiology of the Weight Reduced State. Describes physiological adaptations in appetite and energy expenditure that oppose long-term weight-loss maintenance.
Mazgelytė E, Karčiauskaitė D. Cortisol in metabolic syndrome. 2024. Review of cortisol physiology, insulin resistance, visceral adiposity, and metabolic syndrome.
Rodriguez AC, et al. Hypothalamic-pituitary-adrenal axis dysregulation and cortisol activity in obesity: A systematic review. Psychoneuroendocrinology. Review demonstrating inconsistent and complex relationships between cortisol measures and obesity.
Endocrine Society. Statement on Testosterone Replacement Therapy. July 2026. Current guidance regarding obesity-associated low testosterone, reversible contributors, diagnosis, and treatment considerations.
Juppi HK, Karppinen JE, Laakkonen EK. Menopause and Body Composition: A Complex Field. 2025. Review examining menopause-related changes in muscle mass, visceral adiposity, hormonal change, aging, and lifestyle.
American Thyroid Association. Thyroid and Weight. Current patient guidance regarding hypothyroidism, metabolic rate, weight gain, and thyroid treatment.
Anekwe CV, Ahn YJ, Bajaj SS, Stanford FC. Pharmacotherapy causing weight gain and metabolic alteration in those with obesity and obesity-related conditions. Annals of the New York Academy of Sciences. 2024. Review of medication classes associated with weight gain.
Pedersen SD, et al. Pharmacotherapy for obesity management in adults: 2025 clinical practice guideline update. CMAJ. 2025. Current evidence-based guidance supporting individualized obesity pharmacotherapy alongside health-behavior changes.