Metabolism is an area of nutrition and science that has piqued people's interest due to the rise in obesity rates. I often get asked if it is possible to speed up metabolism by eating certain foods or drinking hot or cold beverages. What happens to metabolic speed as you age? Does it slow down? What can you do to make sure it remains steady throughout middle age? These are common questions people have. However, the problem is that although we're learning more about metabolism, science is still emerging. This means we have good guesses, but sometimes what we thought was true can change with new research.
According to the dictionary, metabolism is"the chemical processes that occur within a living organism to maintain life." Most people refer to the Basal Metabolic Rate (BMR) when they refer to metabolism and is the energy your body uses at rest. It is usually measured in calories and maintains body temp, breathing, blood circulation, and cell repair. All of these biochemical processes require energy in the form of calories and are always happening. It is the most significant component of your metabolism, accounting for about 2/3 of the expenditure. This will drop the more active you are, and your BMR is slowest during sleep.
Everyone's BMR is different. It is highest in babies and young people in the growing phase of their lives, pregnant women, and those with higher amounts of lean body mass. For example, if you compare two adults weighing the same, one who may be obese and one who is fit with high amounts of skeletal muscle tissue, the individual with more lean muscle will burn more calories at rest. The good news is that everyone can increase muscle mass; the trick is to do it as safely and consistently as possible.
An accurate BMR can only be obtained by measuring oxygen input and carbon dioxide output. Many BMR calculators account for age, weight, height, sex, and lean body mass. Some of these tools may give you a BMR ballpark figure; however, their accuracy is highly doubtful, and I wouldn't recommend them.
Metabolism slows slightly as we age due to loss of muscle mass and less movement in our daily lives. These are natural tendencies that occur with most people as they age. As stated above, it is possible to counteract this by keeping a strength training regimen of at least two times per week coupled with adequate, brisk exercise most days of the week. Of course, check with your licensed doctor to ensure healthy and safe, and choose an activity you enjoy. The benefits cannot be overstated with some research underlying exercise's role in disease prevention
Temperature also affects the metabolic rate, and the body spends about 40% of its BMR to keep an adequate temperature in cold or hot climates. Clients have asked me in the past if it is beneficial to exercise in the cold due to your body using energy to stay warm. Yes, you will burn more calories to keep your body warm, but is it enough to make a difference? It is hard to say without accurate measurement. My advice would be to keep moving. Whether you choose hot or cold weather to exercise, both are good choices, and the benefits will be more muscle building, stress relief, better sleep, and calorie expenditure.
Can you blame a sluggish metabolism for weight gain? The answer is no; the body still needs to expend more energy to move around for people with excessive fat composition. The increased body mass also increases organ size and, in turn, increases the need for energy or calories. Genetics plays a significant role in whether or not someone is prone to weight gain and fat distribution, with metabolism being affected by genetics.
Due to the thermic effect of food, some foods take more energy to digest than others. For example, high-fat meals take more energy to digest because fat has more calories per gram than protein or carbohydrate. There is some compelling research that suggests that highly processed foods take less energy to digest. As we pour more money into researching certain foods and their effect on weight gain, we realize that a whole food diet high in fiber, produce, and lean protein is the most beneficial for health.
It is nearly impossible to change your Basal Metabolic Rate. However, there are measures you can take to help increase metabolism overall. Focusing on healthy habits is the best way to change health for the better, including diet, muscle building, and movement.