Is your metabolism friend or foe?
Why is it some people can eat as much as they want and not seem to gain an ounce, while others seem to gain weight just looking at food? These are representations of opposite ends of the metabolism spectrum.
While some people are quick to make conclusions about their metabolism, reducing it to a genetic blueprint and throwing in the weight-management towel, others set unrealistic expectations, untimely or irrelevant to their personal body.
The burning questions are:
can we alter our metabolism?
if so, how?
and how much?
Furthermore, understanding why is also important, and is the reason every long-term success I’ve had with my clients has always included education. If you understand the purpose of something, instead of just being told what to do, it builds self-efficacy and promotes maintenance. Which brings me to sustainability. We should also be asking ourselves if our course of action is sustainable, and if not, how can we make adjustments to make it so. If it isn’t sustainable, with a few extreme exceptions, it’s not worth doing.
Much of the “one size fits all” information about metabolism floating around is due to fanatical trends in health, fitness, and nutrition. Taking a closer look at what is supported by science can help us gain the understanding we need to maintain a healthy, balanced metabolism.
What is BMR (or Basal Metabolic Rate)?
Our BMR is the rate at which our body spends energy at rest for maintenance activities such as temperature control, cell production, muscle substance regulation, keeping the lungs inhaling and exhaling, the heart beating (approx. 100,000 x/day!), etc. Two-thirds of the energy the average person spends in a day supports the body’s basal metabolism.
Factors that Influence BMR
Exercise: The more physically active you are, the more calories you burn overall. BMR will increase with activity level, as the body burns calories to support activity. By exercising regularly, we train our metabolism to stay in higher gear.
Body Composition: Fat tissue has a lower metabolic activity than muscle tissue. As lean muscle mass increases, metabolic rate increases. Ensure resistance training is part of your exercise regime to encourage your body to become a calorie-burning machine.
Stress: Stress may prompt an increase in stress hormones like epinephrine and norepinephrine. This may likewise prompt an increase in heart and respiratory rates, triggering a higher metabolic rate to satisfy these functions. Don’t jump to any silly ideas here though, stress is not necessarily going to help your waistline. It also releases the stress hormone cortisol, signaling your body to hold on to fat. Stress also wears on the body over time in many other detrimental ways. But if you’ve ever wondered why you’ve lost weight in hard times, now you know why.
Age: Our BMR decreases 2-5% per decade after the age of 30. That’s why consuming pizza and beer doesn’t fly as well as it did in our high school days, and also why the habits we set for ourselves in our earlier years matter.
Genetics: Similarly as you may come into the world with your mother’s eyes or your father’s dimples, you may also inherit a predisposition to metabolic rate. This doesn’t mean you can’t alter your BMR, it just means you may need to take more disciplined measures, or it could take you longer. Ensure your goals are realistic and timely to your inherent body type.
Body Size: As weight, height, and surface area increase, a higher BMR is required to support the body.
Gender: BMR averages 5-10% lower in women than in men. This is mainly because women generally possess more body fat and less muscle mass than men of similar size.
Dieting: Weight loss regimens that are too restrictive (provide less daily calories than what is needed to support BMR) will cause a decrease in BMR, as the body attempts to hold on to necessary calories in order to function. This is why crash diets only work in the short term. As our metabolism has been trained to regularly slow down and hold on to calories, in the long run, it negatively affects our weight management.
Growth: during rapid periods of building and development our BMR will increase. This explains why teenagers can eat and eat!
Hot or cold climates: The BMR of people in tropical climates is generally 5-20% higher than their counterparts living in more temperate areas because it takes energy to keep the body cool. Likewise, there is an increase in energy metabolism in cold environments, as it takes more energy to regulate warmth in the body.
Health: Fever, illness or injury may increase resting metabolic rate by as much as double, as the body uses energy to heal.
Hormones: Thyroxine (T4), the key hormone released by the thyroid gland has a significant effect upon metabolic rate. Hypothyroidism is relatively common, especially in women near or after menopause and can contribute to a decrease in BMR.
Women’s cycle (PMS): Right before and up to two weeks prior to menstruation, BMR rises by 10-20%, then during menstruation hormone levels reach their lowest point and your BMR comes back down to normal levels.
Caffeine: Caffeine may increase metabolic rate by approximately 5% after a 100 mg intake (1 cup of coffee). Although caffeine can have a positive influence on our BMR, it is important to personally asses whether caffeine is right for you, in what form your body responds to it best, and most importantly, to ensure you are consuming safe amounts. Too much caffeine can have negative effects.
While we’ve only scratched the surface here on basal metabolic rate, we’ve equipped ourselves with a better understanding of the factors that influence it. We’ve learned what is within our power, so we can better manage our bodies energy expenditure, and hopefully learn to befriend our metabolism.