“My metabolism is so bad, I gain weight really fast and it’s impossible to lose it.”
Most of us have heard some saying this, if not said it ourselves. Many of us blame our metabolism for low energy, or weight gain despite eating less and exercising more. It has become an easy explanation for a body that isn’t responding the way we expect. Metabolism is often seen as the villain working against our health goals. But is it really the villain, or just collateral damage caused by years of unhealthy habits or environmental triggers?
In most cases, metabolism is simply reflecting what’s happening inside the body as a result of poor sleep, unhealthy diet, stress, lack of physical activity, and overall lifestyle.
Metabolism sits at the center of most health challenges. In fact, nearly all major lifestyle diseases such as diabetes, obesity, PCOS, fatty liver, hypertension are now referred to as metabolic disorders. When metabolism is disrupted, multiple systems and pathways in the body start to break down.
What Is Metabolism, Really?
Metabolism refers to all the activities that occur within the body to maintain our life. Contrary to popular belief, metabolism is far more than just digestion and absorption of food; it also involves building and repairing tissues, eliminating waste products, and managing hormones and cellular functions. The energy needed for every single organ in our body to function such as the heart beating, lungs contracting and expanding, kidney purifying the blood and more – all forms part of the metabolic energy spent. Metabolic activity is not a single system but a combination of multiple pathways operating at the cellular level. The energy required to perform these metabolic functions is measured in calories.
One of the core components of metabolism is Basal Metabolic Rate (BMR) — the number of calories your body needs at rest to maintain essential functions like breathing, circulation, temperature regulation, and organ activity. It is interesting to note that metabolic energy spent amounts to nearly 60–70% of total energy expenditure (TDEE) in most people.
Exercise and other normal activities, along with the thermic effect of food (energy used to digest, absorb, and process the nutrients in your meals) accounts only for the remaining 30 – 40% share.
“Metabolism accounts for the lion’s share of your daily energy expenditure”
How to measure my metabolism?
When people ask, “What is my metabolism?” They are usually referring to how many calories their body burns in a day, or whether their metabolism is “slow” or “fast.” Your metabolic rate is not a constant number; it may vary every day, based on the food you eat, stress you undergo, outside climate and more. However, the metabolic rate may settle within a range for every person, based on their health, age, weight and many other factors.
There are certain mathematical equations and models to assess our metabolic rate, based on inputs such as age, weight, height, and sex. However, these equations give only a rough idea of how many calories your body needs at rest. Two people with the same age, weight, height and sex can still have different metabolic rates, even though the equations give the same number for both.
These days, there are wearable devices and smartwatches that give approximations of metabolic rate using heart rate and movement data, but even they too are not reliable and are only approximations. Blood tests can offer indirect insights into metabolic health rather than “metabolic rate.” Markers such as fasting insulin, HOMA-IR, triglycerides, HbA1c, liver enzymes (like ALT and AST), and thyroid hormones (TSH, Free T3, Free T4) can help in identifying metabolic disorders such as insulin resistance, hypothyroidism, etc.
In summary, you can’t measure metabolism to a single number. However, you can assess metabolic rate and overall metabolic health using clinical tests, predictive equations, and activity tracking. These numbers are only indicative and cannot be looked at in insolation to derive any meaningful conclusions.
Can You Boost Your Metabolism?
The phrase “increase metabolism” is quite often used among health enthusiasts, but it’s important to differentiate between increasing and improving metabolism. Scientifically, increasing metabolic rate beyond normal levels isn’t always healthy. For example, people with hyperthyroidism have abnormally high resting metabolic rates, which leads to unintended weight loss, muscle wasting, and cardiovascular stress. Similarly, smokers often have a higher metabolic rate due to nicotine-induced sympathetic nervous system activation and higher heart rate, but that’s clearly not a sign of good health.
The goal, therefore, is not just to “speed up” metabolism, but to optimize it – meaning a metabolic rate that supports energy balance, hormonal health, muscle maintenance, and fat regulation without pushing the body into stress or breakdown. One should strive towards ‘improved metabolism’ instead of ‘increased metabolism’ – an improved metabolism is one that functions efficiently, stays within healthy ranges, and supports long-term physical and metabolic health.
One of the most effective ways to improve metabolism is by improving the body composition – i.e by increasing lean muscle mass and reducing excess body fat. Muscle tissue is metabolically 3x – 4x times more active and burns more energy at rest compared to fat tissues. On average, 1 kg of muscle burns about 13–15 kcal/day at rest, while 1 kg of fat burns only around 4–5 kcal/day. This means that people with higher muscle mass naturally have a higher basal metabolic rate (BMR), which supports better weight regulation and metabolic function.
There are no quick fixes or panacea to boost metabolism. No herb, seed, medicine or food can act as a quick fix to improve or boost your metabolism. Consistent resistance training, combined with adequate protein intake and recovery there by improving body composition, is the only way out. When muscle quality and quantity increases, resting energy expenditure goes up, which is often what people are referring to when they say they’ve “boosted” their metabolism.
Lifestyle Habits That Slow Metabolism
For sure, the metabolism is bound to slow down gradually, and gets impaired as we age. However, many other factors such as our lifestyle choices, body composition, muscle vs fat mass, hormone balance, etc also impacts our metabolism and metabolic rate. One major factor behind a declining metabolism is age-related sarcopenia – the gradual loss of muscle mass and strength that typically begins after the age of 30. As muscle mass decreases significantly due to inactivity, low-protein diets, or insufficient resistance training, metabolic rate also declines, leading to reduced calorie expenditure even at rest. This makes weight maintenance more difficult and increases the risk of fat accumulation and lifestyle diseases over time.
Also Read: Obesity & Sexual Health
Chronic calorie restriction to lose weight, especially when combined with low protein intake and excessive cardio, also can backfire and bring down basal metabolic rate. This is what happens when people often skip meals or survive on salads and smoothies to lose weight. The body perceives this as a survival threat and reduces energy expenditure by lowering thyroid hormone activity, reproductive hormones, and spontaneous movement (NEAT). This is often seen in people who crash diets without proper resistance training or recovery.
As they lose weight with such a crash diet, they often lose muscles also along with fat. And with lower muscle mass, metabolism crashes further and such a person is prone to gaining weight faster. This is the reason why such crash diets often give only temporary weight loss and the person eventually gains fat as they get to normal eating habits.
Another common cause of low metabolism is hypothyroidism, a condition where the thyroid gland produces insufficient amounts of thyroid hormones – T3 and T4. These hormones play a crucial role in regulating basal metabolic rate by controlling how efficiently cells convert nutrients into energy. When thyroid hormone levels drop, the entire metabolic system slows down, energy production decreases, fat oxidation is impaired, and thermogenesis (heat generation) reduces. This leads to symptoms like weight gain, fatigue, cold intolerance, and reduced exercise capacity. Hypothyroidism can also lead to fluid retention and slower gastrointestinal motility, compounding the sensation of “metabolic slowdown” even when calorie intake is not excessive.
Sleep deprivation and chronic stress are other reasons for low metabolic activity, due to increased cortisol levels, which in turn affect glucose metabolism, insulin sensitivity, and fat storage patterns. Cortisol may also suppress thyroid function, further reducing resting metabolic rate. Lastly, sedentary behavior has a compounding effect. A lack of both structured exercise and everyday movement (like walking, climbing stairs, or standing) significantly reduces NEAT which can vary up to 2,000 kcal/day between individuals. This is the reason why two people with similar diets and workouts get very different results.
Metabolic Disorders: When the System Starts to Break Down
Metabolic disorders occur when the body’s ability to convert food into energy, or regulate that energy efficiently becomes impaired, often due to hormonal or enzymatic dysfunction. These disorders involve disturbances in glucose metabolism, fat processing, insulin signaling, and hormonal regulation, often affecting multiple systems in the body. The most common examples of metabolic disorders are type 2 diabetes, insulin resistance, dyslipidemia, fatty liver, hypothyroidism, and polycystic ovarian syndrome (PCOS).
Also Read: PCOS & its impact on Fertility
It is important to note that these conditions are not isolated issues and are often interlinked and progress over time if underlying causes are not addressed. While some metabolic disorders may be due to genetic or autoimmune reasons, the vast majority of them occur due to a bad lifestyle.
Metabolic disorders are now among the most common and costly health conditions globally. According to WHO and other health bodies, metabolic syndrome affects up to 1 in 3 adults in urban populations, especially in countries like India where sedentary jobs, dietary changes, and stress have become widespread. India is already being referred to as the diabetes capital of the world, with rapidly rising cases of type 2 diabetes, prediabetes, and insulin resistance, even among younger populations.
These metabolic diseases don’t just impact individuals, they also strain the healthcare system and create a significant economic burden for families. Increased medical expenses, higher insurance premiums, loss of productivity, long-term complications, reduced quality of life and added financial stress are all end results of poor metabolism.
Many of these issues are preventable and reversible especially in their early stages. By focusing on sustainable lifestyle interventions like strength training, better nutrition, sleep hygiene, stress management, and regular movement, one can protect and even improve their metabolic health. Remember – a person with optimal metabolic function tends to look and feel healthier, both physically and mentally, often appearing more energetic, youthful, and resilient.
