A popular topic among certain dieting circles is the notion that ‘some people are blessed with a fast metabolism, appearing to eat whatever they want without gaining weight’. We’ve all heard similar comments before, but does this concept really hold true from person to person? Here’s an overview of how your metabolism works and if it really makes a big difference…
Firstly, it’s important to understand what resting metabolic rate (RMR) is. Your RMR simply refers to the amount of energy required by your bodily organs to stay alive and accounts for approximately 70% of total energy expenditure (in sedentary individuals). With that in mind, is it possible that seamlessly lean individuals have a higher (faster) metabolic rate when compared to those who struggle with weight loss and/or weight maintenance?
Although there can be differences in RMR between individuals, the difference is a lot less than often assumed. In fact, the majority of people remain within 200-300 kcal (the equivalent of a chocolate bar) of the average RMR.
The greater discrepancy among sedentary individuals and the most variable component of total daily energy expenditure is NEAT (non-exercise activity thermogenesis) and other exercise-based activities. NEAT involves spontaneous activities such as fidgeting, maintaining one’s posture, walking etc. and may be responsible for an individual’s predisposition for weight gain. Another exercise is anything structured, such as the gym or sport.
To sum up, it is true that some people find it harder than others to lose weight but the slow-metabolism rationale as a preventative cause is often over exaggerated. Logically, it’s the structured exercise and your daily activity (NEAT) that makes up the biggest difference. So, next time someone tells you it’s their metabolism causing weight gain, you may want to remind them that for 99% of people without metabolic issues, it’s actually their daily activity that alters the majority of differences in individual calorie burn.
Author: Rudy Mawer, MS – International Sports Scientist & Nutritionist