Does Our Metabolism Really Slow Down As We Age?
By Cassandra Forsythe-Pribanic, PhD, RD, CSCS
Is it possible to maintain our leanness and muscularity as we age? Or, should we just enjoy it while we’ve got it and not fight fate?
Well, first think about this: About 40% of the calories we expend every day, called our Total Energy Expenditure, is due to the amount of activity we engage in.
Part of this activity is exercise, but another part is called NEAT, which stands for non-exercise activity thermogenesis and consists of spontaneous physical activities such as fidgeting, but also any activity outside of formal exercise programs (like washing dishes or sweeping).
Both of these together are called Activity Energy Expenditure or AEE.
Now, compare your AEE now, to your AEE 10, 20 or even 30 years ago? Are you doing the same amount of physically activity, which includes gym or game time, plus daily movements as your younger years? Or, are you considerably less active?
If you’re like most North Americans, you’re probably a lot more sedentary than you used to be. From long commutes to work, to hours on an office chair, to lengthy business meetings and then busing your kids to soccer practice, then gymnastics and Tae Kwan Doe, you definitely move a lot less now than you did when you were younger – especially if you have kids.
For myself, 10 years ago I was walking to and from my classes at college all day long. Then, I’d hit the gym for at least 2 hours (yes, it was a long time, but I didn’t really like studying and used every excuse not to), followed by working long shifts as either a server or clerk where I was constantly on my feet. Also, if I ever had to go anywhere other than school or the gym, I’d bike or walk, but never, ever drive.
Compare that to now, where I have to drive everywhere (I swear, I’ve driven more in the past 5 years than I ever have in all the previous years of my life, not by choice, but because it’s now impossible to walk or bike), I sit for many hours at a computer writing articles like this, then, I manage to get in at least a few hours of teaching exercise classes, followed by house work and chasing around a 13 month old.
Yes, it’s not complete laziness, but it’s definitely a lot less than a decade ago.
And, this decline in activity impacts how many calories we burn each day, in addition to how much muscle we have (you’ve heard the phrase “Use it or lose it”, right? Well, it’s true).
So, this is the first issue. If you want to prevent your metabolism from dropping when you get older, and do everything possible to not end up looking like your overweight parent, you’ve got to keep moving!
Specifically, exercising with a mixture of both aerobic and strength activities is going to give you the best bang for your buck. Physical activity also preserves lean muscle mass, so in addition to a fast metabolism, you’ll keep your toned tummy.
Researchers have shown that aerobic capacity and exercise volume are positively correlated with the amount of calories your burn each day. This means that both the intensity and amount of exercise you do is important.
Further, for men, maintaining a high energy intake along with high energy expenditure is important for keeping their metabolism going strong. For women, this isn’t found to be the case. But, calories are important for giving you the energy to actually be physically active.
Regular physical activity additionally has the benefit of helping people maintain normal cognitive function, such as memory, processing time, and executive function, while reducing or delaying the risk of late-life dementia.
Sounds pretty good, right? Then get off your butt and get moving to help not only keep your leanness, but preserve brain power!
But can we really prevent out metabolism from slowing down?
According to experts in this area of aging research, it looks like no matter what we do, we can’t really prevent our metabolisms from slowing down completely.
It’s just like aging: there’s no such thing as anti-aging. Regardless of what we do, we’re still going to age. The Fountain of Youth doesn’t really exist.
As we age, the metabolic function of our muscles and organs change, such that we become worse at oxidizing (burning) fats and carbs, and better at storing them. We also have a harder time making muscle and other important tissue like healthy skin and bones.
However, older adults who are more fit are proven to have more muscle and less fat, but the rate of decline in muscle loss and metabolic rate is similar for all adults regardless of fitness level.
But the bottom line is that if you start out with more muscle, it’ll take longer to break it down and you’ll still have more than your sedentary roommate in the nursing home when you die.
What should we eat to maintain a fast metabolism?
Recently, a large group of researchers collected prospective data from a cohort 3,075 older adults in something called the Health, Aging and Body Composition (ABC) study. From this information, many different discoveries have been found, but one of them that was particularly applicable to this discussion was what healthy older adults eat to stay lean.
Although this study only used food frequency questionnaires (FFQ) to analyze diet, which is subject to reporter bias, it was found that there were six dietary patterns that were associated with healthy survival over a 10 year period:
3. Whole Grains
6. Low-fat (not fat-free!) Dairy
Basically, when you include plenty of fruit and vegetables, which are rich in age-fighting antioxidants, whole grains like rice (not bread!), turkey, chicken, eggs, and salmon, along with low-fat yogurt, you’re getting nutrients that help you live a long, healthy life.
It also suggests that red meats may not be the answer to a long life, but that may be up for debate as the FFQ often lumps red meat with processed high-salt, nitrite-containing meat products. And, not-so-healthy vegetable oils/soy bean oils, are usually combined with good oils like olive and flax, so it’s hard to say these are life-shortening or not.
In addition to this data, we can compare with information from the dietary habits of healthy centarians (people who live healthily past 100 years). From the well-researched book, Blue Zones, by Dan Buettner, five Blue Zones have been identified in the world:
• Sardinia, Italy
• Okinawa, Japan
• Loma Linda, CA
• Nicoya Peninsula, Cost Rica
• Icaria, Greece
In these areas, there are certain common nutrition and physical habits that they all display:
• They consume plenty plant foods, such as fruits, vegetables, beans, nuts and seeds and real whole grains (grains, not breads)
• They do not smoke
• They drink moderate wine and tea
• They do not stress when they eat
• They include powerful spices like turmeric and cayenne
• They maintain a consistent high level of physical activity
Now, since I’ve never really seen these Blue Zone people in person, I can’t say if they’re incredibly lean and attractive, but what I do know is that most of them are much leaner than most older North American adults, and don’t suffer from dementia or a decline in quality of life – which is just as important as keeping your six pack of abs.
Living Long and Living Lean
So, ladies: if you want to avoid the thunder thighs and tummy pooch that your mother carries around, and guys, if you want to avoid your dad’s beer gut, do everything you can to stay very physically active your whole life and eat real food, not processed junk.
Don’t let kids get in your way of a healthy exercise routine and daily movement. Instead, be active with your kids, and that doesn’t mean just driving them around to every activity you can cram in their day. And, don’t make the excuse that you have to eat excessive amounts of candy, or refined foods because that’s all your kids eat. If you let them only eat that, it’s your own issue, but don’t fall into the same trap yourself.
If you’re not a parent, don’t let work or extended happy hour ruin your daily lift or run. Your life (and lean body) is too important to throw all away in just a few years of a new corporate position. Work is not life, and it won’t buy you liposuction when you develop more cellulite lumps than a bowl of cottage cheese.
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Health ABC information: https://www.nia.nih.gov/ResearchInformation/ScientificResources/HealthABCDescription.htm
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