Operation Resiliency | Clinical Commentary August 2026
Written by Michael Murphy, MSN, PMHNP-S
Many people assume that losing weight is simply a matter of eating less and exercising more. While those habits are essential, they’re only part of the equation. Research has shown that hormones, metabolism, medications, stress, sleep, and mental health can all influence how your body responds to weight-loss efforts.
Understanding these factors isn’t about making excuses, it’s about understanding the science. Once you know what’s affecting your weight, you can make more informed decisions and develop a strategy that’s tailored to your individual needs.
In this article I will address the following topics:
- Weight Loss Is More Complex Than “Calories In, Calories Out”
- Your Body Is Designed to Resist Weight Loss
- Mental Health Can Influence Weight Loss More Than Many People Realize
- Some Medications May Also Affect Your Weight
- Emotional Eating Is Often a Symptom, Not a Lack of Willpower
- Why It Is Still Worth Trying
- When Should You Talk to a Doctor About Weight Loss?
Weight Loss Is More Complex Than "Calories In, Calories Out"
For years, weight loss has been simplified to one basic principle: burn more calories than you consume. While energy balance certainly matters, modern research has shown that the human body is far more complex than a simple math equation.
Your genetics, hormones, medications, sleep quality, stress levels, and mental health all influence how many calories you burn, how hungry you feel, and how your body stores fat. Two people can follow the same diet and exercise program and experience very different results because their bodies are responding differently behind the scenes.
This doesn’t mean calories don’t matter, it means they’re only one piece of a much larger picture.
Your Body Is Designed to Resist Weight Loss
One of the biggest surprises for many people is that your body doesn’t necessarily want to lose weight.
As you lose weight, your brain responds by producing hormonal changes designed to protect your energy stores. Levels of leptin, the hormone that helps you feel full, decrease. At the same time, levels of ghrelin, often called the “hunger hormone,” increase, making you feel hungrier than before.
Your metabolism may also slow through a process called adaptive thermogenesis, meaning your body begins burning fewer calories while performing the same daily activities. These natural adaptations helped humans survive periods of famine throughout history, but today they can make long-term weight loss significantly more difficult.
For many people, these biological changes, not a lack of motivation, are the reason progress slows or plateaus over time.
Mental Health Can Influence Weight Loss More Than Many People Realize
Physical health and mental health are closely connected, and both play an important role in weight management.
Depression can reduce energy, motivation, and physical activity while increasing cravings for highly processed comfort foods. Anxiety may contribute to chronic stress, disrupted sleep, and elevated cortisol levels that influence appetite and eating behaviors. Even everyday stress can make it more difficult to prepare healthy meals, exercise consistently, or maintain routines that support long-term success.
Mental health doesn’t directly cause obesity, but it can create barriers that make healthy habits more difficult to sustain. Addressing those barriers is often an important part of creating a successful weight-loss plan.
Some Medications May Also Affect Your Weight
For some individuals, medications may be contributing to weight changes as well.
Certain antidepressants, mood stabilizers, and antipsychotic medications have been associated with weight gain or changes in appetite. These medications are often essential for treating mental health conditions, and they should never be stopped without guidance from a healthcare provider. However, understanding their potential impact on weight can help patients and physicians develop strategies to minimize unwanted side effects while continuing appropriate treatment.
The goal should never be choosing between your mental health and your physical health. With individualized care, it’s often possible to support both.
Emotional Eating Is Often a Symptom, Not a Lack of Willpower
Many people assume emotional eating is simply a matter of self-control. In reality, it is often a response to stress, anxiety, loneliness, boredom, or other difficult emotions.
Food can temporarily activate the brain’s reward system, providing comfort during emotionally challenging moments. While this response is completely human, relying on food as a primary coping strategy can make long-term weight management more difficult.
Recognizing emotional eating patterns without guilt or shame allows people to develop healthier coping strategies that support both emotional well-being and physical health.
So, Why Is It Still Worth Trying?
Understanding the biological and psychological challenges of weight loss isn’t about making excuses, it’s about replacing frustration with knowledge.
While factors like hormones, metabolism, mental health, and medications can make weight loss more difficult, they do not make success impossible. The most effective weight-loss plans recognize that every person faces different obstacles and that lasting results often require more than a one size fits all diet.
A personalized approach that considers medical history, lifestyle, nutrition, physical activity, behavioral health, and, when appropriate, physician-supervised treatments can help address the factors that may be standing in your way.
When Should You Talk to a Doctor About Weight Loss?
If you’ve consistently made healthy lifestyle changes but aren’t seeing the results you expect, it may be time to speak with a healthcare provider.
Difficulty losing weight isn’t always a matter of effort. Hormonal changes, underlying medical conditions, medications, and mental health challenges can all influence your progress. Identifying those factors can help you develop a plan that’s based on your unique needs instead of trial and error.
Frequently Asked Questions
Can depression cause weight gain?
Depression can contribute to weight gain through changes in appetite, activity levels, sleep, stress hormones, and shared biological pathways that influence metabolism.
Can anxiety make it harder to lose weight?
Yes. Chronic stress and anxiety can affect eating behaviors, sleep quality, and hormone regulation, all of which may influence weight management.
Why do antidepressants cause weight gain?
Some antidepressants can increase appetite or affect metabolism. Not everyone experiences this side effect, and the degree of weight gain varies depending on the medication and the individual.
Is slow metabolism the main reason people can't lose weight?
Not necessarily. While metabolism changes during weight loss, research suggests that behavior, mental health, medications, and other biological factors also play important roles.
Should I talk to a doctor if I can't lose weight?
If you’ve consistently followed healthy nutrition and exercise habits without seeing results, it’s reasonable to discuss your concerns with a healthcare provider. They can evaluate for medical conditions, medication side effects, hormonal changes, and other factors that may be affecting your progress.
Final Thoughts
Weight loss is rarely as simple as eating less and exercising more. Biology, psychology, lifestyle, and medical conditions all work together to influence how your body gains, loses, and maintains weight.
Rather than viewing slow progress as a personal failure, consider it an opportunity to better understand your body. The more we learn about the science of weight management, the clearer it becomes that successful weight loss isn’t about finding more willpower, it’s about finding the right strategy for you.
If you’ve been making healthy lifestyle changes but still aren’t seeing the results you expected, you don’t have to figure it out alone. A comprehensive medical evaluation can help identify the factors that may be affecting your progress and determine whether physician supervised weight loss, nutrition counseling, behavioral support, or other treatment options are appropriate for your individual needs.
At Operation Resiliency, our goal is to help you understand what’s standing in the way of your success and develop a personalized plan that’s realistic, evidence based and designed for long-term health. If you’re ready to take the next step, schedule a consultation with our weight loss team to discuss your goals and explore the options available to you.
Sources
This article references research from the American Journal of Clinical Nutrition, StatPearls clinical review on the metabolic consequences of weight reduction (2025), Harvard Health summaries of long-term metabolic adaptation research, the International Journal of Obesity (2025), Lancet Psychiatry (2025), reviews published through PubMed Central and MDPI examining shared inflammatory and neuroendocrine pathways, and the Frontiers in Psychiatry bibliometric review of obesity and psychology (2025).
This article is intended for educational purposes only and should not replace individualized medical advice.