It's not your age that's slowing your metabolism, new research says. Here's what to do
(CNN)If you're middle-aged and have been slowly but steadily putting on weight for years, you've probably attributed it to an age-related decrease in metabolism.
Your metabolic rate is the rate at which your body burns calories to keep you alive and functioning. It's a generally accepted belief that as you age, your resting metabolism slows --especially over age 40. And if you are a woman in menopause, your metabolism slows even more.
Not true, says a new paper published in Science. By analyzing data from nearly 6,500 people ranging in age from infancy to elderly, the paper's authors determined that resting metabolism holds steady from age 20 to 60 before logging a decrease of less than 1% per year thereafter.
Further countering conventional wisdom, the paper cites no real differences between resting metabolic rates of men and women, even for menopausal women, when controlling for other influences.
Now you might be wondering why you feel like your metabolism has slowed down.
The answer is less about age and more about lifestyle. Although your baseline resting metabolic rate may not have changed between ages 20 and 60, the factors involved in boosting other aspects of your metabolism -- when you are not resting -- likely changed, lowering your ability to metabolize fat, maximize the caloric burn from exercise, increase energy-burning muscle mass and get quality rest to enable metabolic processes.
Don't worry -- this isn't bad news. It actually means that you have the power to make changes that will boost your metabolism, regardless of your age.
Read on for four science-backed ways to boost your metabolism.
Important note: Consult your doctor before beginning any new exercise program.
Be active throughout the day
When asking yourself why you feel like your metabolism has slowed down with age, you should also question whether your daily activity level has slowed down. In addition to all the other health risks associated with prolonged sitting, experts point to consistent inactivity as the biggest detriment to your metabolism.
"Being sedentary most of the day markedly reduces fat metabolism," said Edward Coyle, professor of kinesiology and health education at the University of Texas at Austin.
Fat metabolism refers to the type of fuel you are burning during resting metabolism.
Coyle, who is also the director of the school's Human Performance Laboratory, said his research has found it's necessary to take at least 8,500 steps per day -- throughout the day, rather than all at once -- in order to maintain adequate fat metabolism.
Additionally, in his lab, Coyle has found that just five four-second bursts of exercise performed at full effort every hour throughout the day can dramatically increase fat metabolism by as much as 49%.
Although doing 20 seconds of full-out sprints every hour isn't practical for almost anyone, sedentary office workers whose time limitations and responsibilities make it difficult to get to the gym regularly should take heart that simply getting up and moving a few minutes per hour can pay significant dividends.
Do the right kinds of exercise
High-intensity interval training (HIIT) and strength training have both been shown to have statistically significant impacts on your metabolism.
HIIT is a training style that involves periods of exercising intensely with an elevated heart rate alternated with recovery periods. It has been shown to elevate your metabolic rate, specifically for fat burning, long after your workout ends. One study found that, after 12 weeks of HIIT, overweight men reduced their belly fat by 17% and overall fat mass by 4.4 pounds (2 kilograms), which is comparatively more than other studies on fat burning using alternate forms of exercise. You can learn more about safely performing HIIT here.
With strength training, you increase your body's muscle mass, which increases your overall metabolic rate. Like HIIT, that means more calories burned after exercising. However, unlike HIIT, the muscle you build strength training will continue to burn caloric energy regardless of how often you work out, as long as you are doing enough to maintain muscle mass.
As such, strength training can also help you avoid muscle loss and metabolic decrease associated with dieting for weight loss. In a study of 48 overweight women on a diet of only 800 calories per day, strength training was shown to enable them to maintain muscle mass and metabolism, while those in the study who did only aerobic exercise or no exercise lost muscle and experienced decreased metabolism.
To maximize your metabolic boost through exercise, you should mix up your weekly workout program to include both strength training sessions and HIIT training sessions. That said, it is important to note that to get the most out of any kind of exercise program, you need to also break up long periods of sedentary time during the day with short bouts of activity, as mentioned above.
Doing a one-hour workout would normally increase your fat metabolism, Coyle said. But if you've been inactive all day long, it won't be as effective due to what he referred to as "exercise resistance."
Coyle's research has shown that people who are inactive all day long become resistant to some of the beneficial effects of exercise -- fat metabolism in particular.
That's why it's crucial to engage in spurts of activity throughout your day in addition to doing longer workouts.
Fuel your body with protein and water
Digesting food actually increases your metabolism for a few hours, because it takes caloric energy to process the nutrients you eat. This is called the thermic effect of food (TEF).
That doesn't mean you should eat more in order to boost your metabolism, but if you eat more protein, it can lead to bigger boosts in metabolism than other foods. That is because protein causes the largest rise in TEF, increasing your overall metabolic rate by 15% to 30%.
Eating protein is also essential for building and repairing muscle, which -- as established above -- boosts your metabolism. Additionally, ingesting protein helps you avoid muscle loss and the resulting decrease in metabolism that can come with dieting.
Registered dietician and Eleat Sports Nutrition owner Angie Asche, who is the author of the book "Fuel Your Body: How to Cook and Eat for Peak Performance," advised eating 20 to 25 grams of protein within an hour after working out.
That's equal to a 3-ounce chicken breast (24 grams of protein), one 7-ounce container of 2% Greek yogurt (20 grams) or one scoop of whey or plant-based protein powder (grams of protein varies depending on brand).
Drinking more water may also briefly raise your metabolism. Research shows that drinking 0.5 liters of water can increase resting metabolism by 24% for about an hour. Additional research points to a possible enhanced metabolism boost if you drink cold water because of the energy expenditure needed to heat it to body temperature.
Get the rest you need
Sleep is crucial for the recovery and restoration of all of the processes of your body.
Sleeping fewer than seven hours on a regular basis is associated with numerous negative health implications, like weight gain, diabetes, hypertension, heart disease and stroke, depression, impaired immune function, increased pain, impaired performance, and greater risk of death, according to the American Academy of Sleep Medicine and Sleep Research Society.
When it comes to the harmful effects of lack of sleep on body processes, metabolism is no exception. Sleep deprivation and reduced quality of sleep have been shown in research to have a detrimental impact on metabolism.
The US Centers for Disease Control and Prevention reports that 1 in 3 Americans don't get the recommended seven or more hours of sleep per night. To get the sleep you need to maintain a healthy metabolism and overall health and wellness, it's important to create a nightly routine that includes strategies that facilitate rest, such as breathing exercises to help calm your nervous system. You can also practice these four yoga moves to prepare your body for sleep.
Research points to the rate of your metabolism, particularly fat metabolism, being largely in your hands. It's up to you to make lifestyle changes that will boost your metabolism and your overall health and wellness.
