Do you remember a time when you could eat anything you wanted and not gain weight? There’s long been an assumption that your metabolism slows down as you get older. If we want to avoid gaining weight as we get older, we need to exercise more and eat less.
But a new study suggests your metabolism, the rate at which you burn calories, doesn’t slow down as you get older!
Four Pennington Biomedical researchers were part of an international team of scientists who analyzed the average calories burned by more than 6,600 people as they went about their daily lives. The subjects ranged from newborn to 95-years-old and lived in 29 different countries from various ethnic backgrounds and cultures. The results were almost exactly the opposite of what our observations might have led us to believe.
To come up with a number for total daily energy expenditure, the researchers used a sophisticated technique called the “doubly labeled water” method. It’s a urine test that involves having a person drink water. The hydrogen and oxygen in the water molecules have been replaced with naturally occurring “heavy” forms and then measured how quickly they’re flushed out. This method is considered the gold standard for measuring daily energy expenditure (the total calories you burn in a given day).
Our metabolic rate is highest when we are babies, peaking at about 12 months of age. It then slows down by about 3 percent each year until our 20s, when it levels off into a new normal.
Another surprise? People’s metabolisms were remarkably stable from age 20-60. There is virtually no slowing in midlife.
So then, why do so many people gain weight in Their midlife?
The answer is simple; we are eating more and moving less.
We can go the entire day without raising our heart rate. With a press of a button from our cars, elevators, phones, televisions, and microwaves, everything can be done.
Never before in our history can we be so lazy and have constant access to high-calorie good tasting food. In less than 20 minutes, we can drive through a fast food joint and quickly consume over 2,000 calories, and all we have to do is use our fingers to retrieve it.
We repeat this behavior for years and don’t forget to add in the high-calorie parties and holidays. The pounds continue to add up while never getting burnt off.
Furthermore, we gain weight as we get older because:
- Your kids are older, so you’re not catering to their every need
- Your workouts aren’t as long or intense as they once were.
- You might feel stiff and achy, so you move less. (Unfortunately, inactivity accelerates this process.)
- Your leisure activities are less active than they used to be
- Changes in hormones
- When we use our bodies less, our body composition also changes. We lose muscle mass, which further reduces the number of calories we burn at rest. So, in that sense, our metabolism might be slowing down—but not due to our age. Instead, it is slowing due to lifestyle choices.
The truth is, most people are very unaware of how much they consume and how little they move.
The following change seems to occur around age 60 when the metabolism does indeed start to slow. The slowdown is gradual, only 0.7 percent a year. A person in their 90s needs 26 percent fewer calories each day than someone in midlife.
How To prevent midlife weight gain
The good news is that much more of this may be within our control than we previously assumed. Make sure you are doing most or all of these:
- Track your food in a food tracking app to know exactly how many calories you eat a day. I like MyFitnessPal
- Move more – aim to get 10,000 steps a day.
- Strength train – if you need a strength training program, check out my FIT Babes ebook that has 6-weeks of home workouts.
- Switch up your cardio. Your body gets used to doing the same cardio, which means over time, you won’t burn as many calories as you once did. If you ride your bike every day, switch to walking, swimming, etc., at least two days a week.
- Increase the amount of weight you lift or how many reps or sets you do.
- Eat protein with every meal and snack. Protein helps keep you fuller longer, which can make it easier to curb over-eating. It also helps us build and maintain muscle tissue (along with an effective workout program), which helps us burn more calories at rest (while you read this blog post).
aftannFIT Protein Tip: Meat, eggs, fish, and dairy, are the best protein sources. Beans, legumes, grains, nuts, and seeds also provide protein, just not nearly as much per serving. It takes more servings of plant-based foods to provide the same amount of protein you’d get from fewer servings of most animal-based foods.
If you need help with your diet or workouts, I offer personal and group training in Huntington Beach, California. If you don’t live in the area, I have an online FIT12 Program or Customized Meal Plan.
This research was supported by the United States National Science Foundation (BCS-1824466), the International Atomic Energy Agency, Taiyo Nippon Sanso, and SERCON. Other Pennington Biomedical scientists are Peter Katzmarzyk, Ph.D., Associate Executive Director for Population and Public Health Sciences; Corby Martin, Ph.D., Professor and Director, Ingestive Behavior Laboratory; and Eric Ravussin, Ph.D., Associate Executive Director for Clinical Science.