Slow Metabolism: Is it Genetics or Hormones? | How to Tell
Metabolism is the engine of your body. It is the complex internal process that converts food you eat and oxygen you breathe into energy to keep you alive and to be able to move. For many people, the “engine” of their metabolic rate can be a source of endless worry and frustration at times when they perceive themselves to be following the “right” protocol of eating healthy and exercising, but the scale continues to remain at the same number or even rises, whereas others appear to eat whatever they want and not have this same experience.
Many people face the same difficulty of trying to determine if they have an inherently sluggish metabolism. It’s easy to chalk it up to bad luck, but in reality it boils down to one of two things: either your genetic make-up has predetermined how quickly your metabolism will be (i.e. your genetics), or your hormone levels are out of balance for some reason. This article will help clarify both of these possibilities, and give you some tips for finding out what is really holding back your progress, so you can start taking positive steps forward.
How Metabolism Is Referred To As A Power Source Of The Body?
Metabolism is frequently referred to as the power source of the body. It converts certain nutrients (food) and oxygen into usable energy for living, working and functioning. For many individuals, it can be a source of frustration to believe that they are eating a healthy diet, exercising, and attempting to improve their health without seeing any change in their weight or their friends and/or family with high blood sugars showing no signs of those problems.
What Is a “Slow Metabolism”?
When individuals refer to having a slow metabolism, they are typically discussing the Basal Metabolic Rate (BMR). BMR reflects the lowest number of caloric intake required by the body to conduct basic bodily functions that are needed to provide life sustaining activity or necessary functions to keep you alive (for example: respiration, circulation, cell repair) while in a state of rest. BMR represents the lowest amount of calories needed to provide an individual with energy “idle”.
Although BMR and metabolism are often used interchangeably, there are significant differences between the two, including weight gain and fat storage. Metabolism is the transformation of energy, while weight gain occurs from an imbalance of the energy consumed versus the amount of energy that is expended. Additionally, fat serves as a reservoir of energy, allowing the body to store the greater amount of energy consumed.
Moreover, the frequently discussed misconception in many health and wellness-related discussions is the idea that people “damaged” or have “broken” metabolism. Metabolic rates may certainly decrease as a result of malnutrition, extreme dieting or a result of time as we age; however, it is highly unlikely that an individual could be completely at harm or destroyed.
Genetic Impact on Metabolism
Though it is extremely common to attribute full control over our metabolism to things like diet and exercise, genetics has a major role in determining how fast or slow we metabolize food and other substances.
Basal Metabolic Rate
Genetic factors affect your BMR (Basal Metabolic Rate) through many different biological means, including the type of muscle fibers your body is born with (fast or slow-twitch) and how easily you can accumulate fat versus muscle.
Fast-Twitch & Slow-Twitch Muscle Fibers
For example, someone who is born with more fast-twitch muscle fibers would typically oxidize fuel differently than someone born with more slow-twitch muscle fibers due in part to the fact that fast-twitch fibers burn energy more rapidly.
Genetic Regulation of Hunger and Energy Use
Some genes are responsible for regulating an individual’s “baseline” hunger and energy use; therefore, even when you’re not eating, there is a minimum level of energy expenditure your body will use (i.e., the “idle” speed of your body) when it isn’t processing food.
Family History as a Clue
An indication that your metabolism is slow due to heredity is a strong family history; if there is a history within your immediate family – parents and siblings – of weight loss to maintain healthy body compositions despite positive lifestyle choices, and then it is likely that you have inherited those same characteristics.
Genetic Influence on Weight Loss Ability
Genetics may have played an important role in your ability to lose weight; therefore, if you consistently exhibited behaviors that made you feel it had always been difficult for you to gain weight, such as having a harder time shedding excess pounds than other people who are of normal weight and maintain a healthy body composition, it may be that your genes predisposed you to a lower metabolic rate.
Genetic Blueprint for Energy Conservation
Biomarkers of health such as energy level and mood are consistently found to be favorable in conjunction with lower rates of fat loss when compared with those of the same gender/body type who maintain healthy body composition through healthy eating habits, regular exercise, and consistently maintaining a healthy energy balance. It is likely that your genetic heritage has provided you with a blueprint for conserving energy throughout your life.
Hormones and Metabolism — the Hidden Drivers
Unlike genetics, which set the baseline, hormones are the true managers of your metabolism. They can increase or decrease energy expenditure depending on your environment, health, and stress levels.
The Major Hormones That Influence Metabolism
Thyroid hormones (T3, T4): Produced by the thyroid gland, these hormones regulate how quickly every cell in the body uses energy.
Insulin: Made by the pancreas, insulin controls how the body uses and stores glucose. Elevated insulin levels often signal the body to store fat rather than burn it.
Cortisol: Commonly called the “stress hormone,” cortisol helps the body respond to stress. However, chronically high levels can force the body to conserve energy and store fat, particularly around the midsection.
Leptin and Ghrelin: These are your hunger and fullness hormones. Ghrelin tells you when it’s time to eat, while leptin signals the brain that enough energy has been stored.
Sex hormones (Estrogen, Testosterone): These influence muscle mass and fat distribution. Low testosterone or imbalanced estrogen can significantly slow metabolic activity.
If your metabolism has slowed down and you’re experiencing other physical symptoms, the cause may be hormonal rather than genetic. Some frequent imbalances include:
Hypothyroidism: An underactive thyroid that fails to produce enough T3 and T4, slowing the body’s engine.
Insulin Resistance: When cells stop responding to insulin, blood sugar rises and excess fat is stored.
Chronic Stress and High Cortisol: Persistent stress keeps the body in “survival mode,” reducing non‑essential metabolic processes.
PCOS (in women): Polycystic Ovary Syndrome often involves hormonal disruptions that contribute to slower metabolism and weight challenges.
Genetics vs. Hormones — How to Tell the Difference
The first step in determining the right treatment is distinguishing between a genetically slow metabolism (“slow engine”) and a hormonally driven issue (“mechanical failure”).
Genetic Metabolism: Genetic metabolism is generally life long—the majority of individuals with a genetic slowdown experienced more effort to perform compared to their peers at an early age.
Hormonal Changes: Hormonal change typically occurs abruptly and/or occurs in response to a specific life event (e.g., childbirth) or event (e.g., high-stress occupational changes or experiences), as well as trauma from physical or emotional injury.
Hormonal imbalances usually affect more than just weight. They often come with additional symptoms such as mood swings, disrupted sleep patterns, or even temperature fluctuations.
Importantly, the body’s response to treatment for hormonal imbalances can differ greatly from its response to a genetically slow metabolism. For example, while high‑intensity exercise may help someone with genetic metabolic slowdown, it may not be as effective for someone whose metabolism is hindered by hormonal imbalance.
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Tests That Can Help Identify the Cause
To move past speculation about why a metabolic plateau occurs, the most reliable approach is clinical testing. These tests provide the foundation for understanding what’s happening with your metabolism.
The most comprehensive way to investigate the “metabolic thermostat” is through a thyroid function test, which measures TSH, Free T4, and Free T3 levels. Doctors also check fasting glucose and insulin to evaluate fat‑storing tendencies and determine insulin sensitivity.
When stress is suspected as a factor, cortisol testing—often done with a 24‑hour saliva test—can reveal whether the adrenal glands are stuck in “survival mode.” In addition, a broad hormone panel helps assess age‑related changes in testosterone, estrogen, and progesterone.
Finally, while genetic testing such as Nutrigenomics can provide insight into predispositions toward certain macronutrients or appetite patterns, it cannot diagnose current metabolic issues. Most present-day metabolic challenges are driven by hormonal imbalances or environmental influences rather than genetics alone.
What to Do If it’s Genetic
If your slow metabolism is tied to your DNA, it doesn’t mean you’re stuck—it simply means you need a smarter “owner’s manual” for your body. While you can’t change your genetic blueprint, you can optimize how your body burns energy.
Build Muscle First: Make strength training the foundation of your routine. Lean muscle is the most effective way to permanently raise your basal metabolic rate.
Fuel with Protein: A protein‑rich diet not only requires more energy to digest but also helps preserve the muscle you’ve worked hard to build.
Move More, Every Day: Beyond workouts, focus on NEAT (Non‑Exercise Activity Thermogenesis)—small daily movements like walking while on the phone or taking the stairs—to keep your “metabolic fire” burning.
Stay Realistic & Consistent: Progress may feel slower compared to someone with “fast” genes, but consistency ensures your biology never becomes a barrier to long‑term health.
What to Do If It’s Hormone-Related
If your hormone levels are causing your metabolism to misbehave, then the advice to “eat less and exercise more” could cause stress and slow down your metabolism. If your hormones, such as estrogen, testosterone, or cortisol, are imbalanced, your body does not know how to process energy correctly. To correct this, you need to address the problem at its root—not just the symptoms.
Medical Evaluation and Treatment
The most important first step is to have your hormone levels evaluated with a physician who specializes in the endocrine system (endocrinologist). The endocrinologist will conduct evaluations to find out if you have any issues such as: Hypothyroidism (low thyroid), Insulin Resistance or PCOS. Once you have identified your issue(s), he/she can prescribe the appropriate treatment for you. Targeted treatments for these problems will allow you to “unlock” your metabolism that seems to be stalled.
Stress Management
When cortisol levels surge in the body, this causes fat to deposit on the stomach area. Daily deep breathing, meditation, and nature walks help reduce the “survival” signal of cortisol and allow your metabolism to function optimally.
Optimizing sleep
The benefit of sleep is to reset the hormonal balance within the body. For optimal sleep, aim for a total of 7 to 9 hours of quality sleep in a dark, cool environment, as well as to control hair loss and excessive appetite. When sleep is interrupted, ghrelin production increases (the hunger hormone) while leptin production decreases (the fullness hormone); this makes it nearly impossible to manage metabolism through proper food intake.
Balanced nutrition
Do not fall victim to the false belief of “starvation mode”. When you restrict calories, it can further weaken your thyroid and cause high cortisol levels. Nutritional focus should be on eating whole, anti-inflammatory foods, healthy fats and fibre to stabilize blood sugar, and promote hormone production.
Change the types of exercises you do: If you are unbalanced hormonally, too much high-intensity training may overstress your body.
Combined with Other Factors
Most people will not be able to identify why they have a slower metabolism solely from their genes or from their hormones; rather, it is the combination of both. Genetics and hormones work together, and it is necessary to understand how they interact in order to overcome the plateau of weight loss.
How Genes and Hormones Interact: Genetics provide the “blueprint” and since hormones provide an “on/off” switch, genes may predispose an individual to have insulin resistance, while hormones will be responsible for activating that predisposition only during periods of heightened stress or when the individual is suffering from a lack of quality sleep.
Vicious Cycle: For many individuals, the combination of being genetically predisposed to slow fat loss combined with the associated weight gain is a vicious cycle, resulting in increased levels of leptin resistance and cortisol production, both of which indicate hormonal imbalances, both of which make it feel as though your body is fighting against you on two fronts.
Personalized Approach: Because every individual has a unique combination of genetics and hormones, “one-size-fits-all” diets are generally unsuccessful; however, in order to achieve weight loss success, the individual must take a personalized approach that focuses on both hormonal triggers and genetics.
Conclusion
A sluggish metabolism is not a dead end. Your body is the starting point, but it can be pushed further. To achieve the goal, you first need to find out the underlying issue—if you realize that slow metabolism is due to a genetic factor or a hormonal imbalance, you will no longer be guessing but rather being strategic. If you have extreme tiredness or sudden weight fluctuations which are very annoying, then don’t hesitate to consult a doctor to get the proper examinations done. With knowledge of your bodily functions, you can embark on a path of control and reap the rewards of your effort.