Does metabolism actually slow down as we age? Here’s what research says

Your metabolism refers to all the biochemical reactions occurring in the body. One of these key reactions is converting food and drinks into energy. Your body uses this energy for vital functions such as breathing, brain power, digestion, repairing muscle, and so much more.¹ The rate at which it works to burn calories to keep your body going is known as metabolic rate. Metabolic rate is unique to every person, and is determined by genetics, age, muscle mass, and activity level. Increasing your metabolic rate is commonly referred to as “boosting metabolism,” meaning there is an increase in the number of calories your body needs while resting and moving. Having a fast metabolism means your body burns more calories. On the flip side, a slower metabolism means your body needs fewer calories and does not convert food into energy as efficiently.

A common question about metabolism is: Does metabolism slow down with age? The answer is yes, your metabolism slows — but not as drastically as you may think.

Keep reading to learn more about why metabolism slows with age, why it matters, and how a slower metabolism impacts your overall health.

Does metabolism slow down with age? Here's what research says

Yes, research has proved that metabolism does slow down with age. While people may assume it’s a gradual decline after young adulthood, your metabolism doesn’t significantly slow down until later in life.

From the age of about 20 to 60, your metabolic rate actually remains pretty consistent. A 2021 study published in Science found that metabolic rate starts to decrease after age 60, by about 0.7 percent each year.² A slow metabolism is often blamed for weight gain later in life. While science does confirm this is a factor for weight gain, there may be other reasons for gaining weight as you age, including decreased activity, loss of muscle mass, diet changes, and how we respond to the food we’re eating.^2,3

Why your metabolism slows down with age

There are multiple reasons why your metabolism slows with age, which may lead to weight gain. As you get older, you lose more muscle mass. Studies have found that muscle mass decreases approximately 3–8% per decade after age 30, and after 60, the rate of decline goes even higher.²

This impacts metabolism because muscle tissue burns more calories at rest than body fat.³ Additionally, other hormonal changes, such as declining testosterone and oestrogen may also play a role in decreasing muscle mass as we age.³

As you age, you may also become less active, which can lead to weight gain. Not only do you burn fewer calories with less movement, but less movement can also contribute to the loss of muscle, which further decreases energy expenditure.⁴

Another cause: as you age, the number of calories your body needs start to decline.² However, many factors may contribute to altered nutrition choices, including eating alone, difficulty cooking or feeding yourself, decreased appetite, or decreased access to healthy food.^4,5 Maintaining balanced glucose levels can also play a role in maintaining a healthy metabolism and weight. Some of the changes in muscle mass seen with ageing may be the result of insulin resistance as insulin plays a big role in the way our body digests and uses protein, along with its effects on glucose.³

Additionally, steady glucose levels have been shown to positively impact your mood, energy levels, mental focus, sleep, and more.⁶ Using a continuous glucose monitor (CGM) like Lingo can help you gain insights into your unique glucose responses and achieve improved metabolic health as you age.

What is the impact of a slower metabolism?

A slowing metabolism may lead to weight gain. However, there are ways you can combat this. Since muscle mass and hormonal changes (including insulin resistance) are some of the main drivers of metabolic changes as you age, both nutrition and physical activity are of the utmost importance:

1. Prioritise protein: Start with a healthy diet that focuses on protein consumption. Older adults struggle to eat adequate protein and they need more protein to support healthy muscles.^3,4 Doing so will benefit your glucose levels, insulin sensitivity, and support muscle tissue.^7,8 Aim to eat 25-35 grams of high-quality protein at each meal.

2. Stay active: Specifically, older adults should focus on strength training. The NHS recommends adults do 75 minutes of muscle strengthening activities at least 2 days a week, and 150 minutes of moderate intensity exercise.^9,10 If time or energy is limited, focusing on strength training and balance exercises will give you the most benefit.¹¹

3. Maintain steady glucose: As we age, the ability of your muscle cells and other tissues to respond to insulin is impaired.³ Focusing on foods that keep glucose levels steady (and in turn, do not require large amounts of insulin) can help, like low-GI foods. Additionally, evidence shows that protein is better metabolised in older adults when consumed without carbohydrates.³ Aim for meals with a quality source of protein, non-starchy veggies, and when eating carbs, make sure they are complex carbs like starchy vegetables or whole grains.

A final note from Lingo

While metabolism does slow down as you age, it’s often much later in life than many people expect. A slowing metabolism may be a factor for weight gain as you get older, but other factors like decreased activity, changes in appetite, loss of muscle mass, and dietary changes can also contribute.

Using a continuous glucose monitor like Lingo can help you understand your habits and patterns and work towards limiting glucose (and insulin) spikes, which can help mitigate the metabolic changes seen with ageing.

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