Agehacking: Can You Speed Up An Aging Metabolism?
Looking back at your early twenties, it can really seem absurd that you could eat junk food and high calorie beverages like soda or alcohol regularly with seemingly little weight consequences. As you progress into your thirties, forties, and beyond, even with portion control and mindful eating it can feel like a struggle to keep weight down. We tend to blame this shift on a slowing metabolism, but what exactly is the metabolism and what can we do to adjust it in our favor?
Put succinctly, metabolism is the chemical processes that occur within a living organism to maintain life. This is a 24/7 operation and includes breathing, pumping blood, digestion, cell repair and replacement, thermoregulation, the whole nine yards. The minimum amount of energy (i.e. calories) that your body requires for this is called the basal metabolic rate or BMR. More specifically, BMR is the amount of energy expended at rest in a neutral environment after your digestive system has been inactive for 12 hours. This is more or less your metabolic rate when you wake up in the morning. Your BMR can account for as much as 80% of your daily energy requirements, depending on your activity levels. Looking at it like this, a slow metabolism is more specifically a low BMR.
So why do some people have a faster metabolism - or higher BMR - than others? Well, body type, age, and gender all play a role in metabolism. Most critically, muscles require more energy input than fat cells. Therefore, people with more muscle run a higher metabolism. As we age, we tend to lose muscle and gain fat. This isn’t the case across all humans and all cultures, but it certainly is given the sedentary lifestyles that have developed in the modern world. This is the main explanation for why we see a shift in metabolism as we age. In addition, men tend to have more muscle mass, denser bones, and less body fat than women, meaning men tend to have a faster metabolism in general. Genes also play a role in dictating muscle mass and body type, therefore affecting metabolism.
So, can we truly blame weight gain on a slowing metabolism?
Turns out there’s not much evidence to support it. Overweight people have faster metabolisms than thinner people, because - logically - larger bodies require more energy to manage the basic processes to maintain life. In fact, only in rare cases are there diseases that actually slow your metabolism and cause weight gain: specifically, Cushing’s Syndrome and hypothyroidism. One of the main hypotheses of weight gain? That we simply eat more calories than we think, and we burn less calories than we think. That is to say, as we age, we underestimate how much we eat, and we overestimate how active we are. Over time, steady increases in calorie consumption and steady declines in daily activity have a huge impact on our waistline.
Then what can I do to speed up my metabolism?
While you do not have much control over your minimum energy requirements (BMR), you do have control over the amount of calories you burn in a day. Burn calories by increasing activity. We all know that the main advice of our doctors is to eat healthy and exercise. Regular exercise will increase your BMR, speeding up your metabolism. In addition, we mention above that muscle requires more energy input than fat. Therefore, as you increase your activity through aerobic exercise and strength training, you in turn will be increasing muscle mass and muscle density. This will adjust your body type to a state that will be burning more calories naturally, thus creating a virtuous cycle. The more you exercise, the more calories you burn, and the more muscle you build, thus doubly revving up your metabolism and burning calories. Remember, weight loss is a numbers game: You need to be burning more calories than you are consuming.
The most important thing is to not be put off by the need to increase exercise to speed up the metabolism. Small gains add up over time. Weekly recommendations for aerobic exercise are 150 minutes per week. When broken down this is only 30 minutes, 5 days a week. Or 20 minutes, 7 days a week. This could be a 10 minute walk in the morning, and a 10 minute walk in the evening. Start where you can, and you will see your metabolism speed up as you increase output.
While there are no cheat codes, here’s one last freebie: studies have found that a compound in green tea - epigallocatechin gallate - helped speed metabolism on average enough to burn an extra 100 calories a day, which can give a small boost to those gains from your increased exercise!