What is the effect of age on your metabolism?

Metabolism slows down gradually as people age, but the extent to which this happens varies greatly from person to person. The biggest factor is not age in itself, but the loss of muscle mass that occurs over the years. The questions below delve deeper into the mechanisms behind this change and what people can do about it themselves.

How quickly does your metabolism change per decade of life?

Metabolism does not change suddenly, but gradually declines over the decades. Research suggests that the basal metabolic rate decreases by a few percent per decade, with the decline becoming more noticeable after the age of forty. This means that a fifty-year-old is more likely to gain weight than at a younger age if eating habits remain the same.

In their twenties and thirties, the metabolism of most people remains relatively stable, provided their lifestyle does not change significantly. Around the age of forty, muscle mass begins to gradually decline, a process known as sarcopenia. Because muscle tissue burns more energy than fat tissue, resting energy expenditure drops accordingly. After the age of fifty, this process accelerates in people who do not actively intervene with strength training or a protein-rich diet.

It is important to realise that metabolism and age do not have a linear relationship. Hormonal changes, such as the drop in oestrogen during the menopause or lower testosterone production in men, also play a role. These hormonal shifts affect both fat storage and muscle building, which indirectly slows down the metabolism further.

Why does metabolism slow down as you get older?

Metabolism slows down with ageing due to a combination of muscle loss, hormonal changes and a decrease in physical activity. Muscle mass is the main driver of resting energy expenditure. As people get older, muscle mass decreases while fat mass relatively increases, which lowers total calorie expenditure.

In addition, hormonal factors play a major role. Growth hormone, which contributes to muscle recovery and fat burning, is produced to a lesser extent as we age. In women, the menopause causes a drop in oestrogen, which changes the distribution of fat in the body and promotes fat storage around the abdomen. In men, testosterone gradually declines, which hinders muscle building.

A third factor is behavioural: on average, people exercise less as they get older, especially when a busy work schedule or physical limitations get in the way of an active lifestyle. Less exercise means less active energy expenditure, which amplifies the effect of the slowed metabolism in ageing further strengthened.

What is the difference between basal metabolic rate and active energy expenditure?

The basal metabolic rate is the amount of energy the body consumes at rest to maintain vital functions, such as breathing, heart rate and cell renewal. Active energy expenditure is the extra energy that is burned through movement, exercise and daily activities. For most people, the basal metabolic rate makes up the largest part of total daily energy expenditure.

In an average adult, the basal metabolic rate is responsible for about sixty to seventy percent of total energy expenditure. This proportion changes with age: as muscle mass decreases, the basal metabolic rate drops, while active energy expenditure also decreases when people become less active.

The distinction is relevant because people who want to work on their metabolism after 40 can influence both components. Strength training increases muscle mass and with it the basal metabolic rate. More daily exercise, such as walking or cycling, increases active energy expenditure. Both strategies together have a greater effect than just watching your diet.

Does muscle mass have more influence on your metabolism than age?

Muscle mass has a greater direct impact on daily energy expenditure than age alone. Muscle tissue burns considerably more calories at rest than fat tissue. A fifty-year-old with a high muscle mass can have a higher basal metabolic rate than a thirty-year-old with low muscle mass and a sedentary lifestyle.

This is an important insight for people who notice that weight and age seem to be increasingly conflicting with each other. Age itself is less determinative than the body composition that has been built up at that age. Anyone who has actively maintained muscle tissue throughout life through regular strength training and sufficient protein intake experiences a less sharp decline in metabolism.

This also means that it is never too late to intervene. Even at an older age, the body responds positively to resistance training. Building muscle mass after the age of fifty is slower, but is certainly possible and has a measurable effect on resting energy expenditure.

Can medication affect metabolism during ageing?

Certain medications can affect the metabolism, both in a positive and negative sense. Some medicines that are commonly prescribed to older people, such as certain antidepressants, beta-blockers or corticosteroids, can reduce energy expenditure or promote fat storage. Conversely, there are medicinal treatments that have been specifically developed to support the metabolism in weight-related issues.

GLP-1 medication is an example of a treatment category that has been receiving more attention in recent years in the context of weight loss. This medication works, among other things, by influencing the feeling of fullness and regulating blood sugar levels, which can contribute to weight reduction in people with overweight or obesity. Results vary per person and a medical assessment is always required before such treatment is started.

It is important that people who take medication and notice that their weight is changing discuss this with a doctor. Adjusting or stopping medication without medical consultation is never recommended. A doctor can assess whether the medication is contributing to weight change and whether adjustments to the treatment plan are sensible.

Which lifestyle factors slow down the metabolism the most?

The lifestyle factors that slow down the metabolism the most are a lack of exercise, insufficient protein intake, chronic sleep deprivation and prolonged stress. These factors reinforce each other and together can have a significant effect on the metabolism, regardless of age.

A sedentary lifestyle is the most direct brake on energy expenditure. People who exercise little lose muscle mass more quickly and burn fewer calories per day. Insufficient protein intake intensifies this effect, because the body needs protein to build and maintain muscle tissue.

Sleep deprivation has a less obvious but well-documented effect on metabolism. Insufficient sleep disrupts the hormonal balance, including the regulation of insulin and cortisol, which promotes fat storage and inhibits fat burning. Chronic stress has a similar effect via increased cortisol levels, which stimulate the storage of belly fat.

• Little movement: reduces active energy expenditure and accelerates muscle loss
• Too little protein: hinders muscle maintenance and recovery
• Sleep deprivation: disrupts hormonal balance and promotes fat storage
• Chronic stress: increases cortisol and stimulates abdominal fat storage
• Very low-calorie diet: can the basal metabolic rate temporarily decrease as an adaptive response

This last point deserves extra attention: an overly restrictive calorie-controlled diet without sufficient protein can trigger starvation mode in the body, causing the basal metabolic rate to drop to conserve energy. This makes boost metabolism in the long run actually more difficult.

How Wellumo helps with weight loss and a sluggish metabolism

For people who notice that losing weight becomes increasingly difficult as they get older, Wellumo offers medical guidance through a fully digital programme. A BIG-registered doctor assesses the situation and determines whether treatment is appropriate and medically sound. Not everyone is eligible, and this is communicated honestly.

What Wellumo offers:

• A medical intake via a questionnaire, assessed by a BIG-registered doctor
• Guidance on weight loss, where GLP-1 medication may be considered following a medical assessment
• Transparent pricing information beforehand, with no hidden costs
• Discrete shipping of medication following approval by a doctor and pharmacy
• Support throughout the entire process, not just with the first order

The process always involves a medical assessment. Prescription-only medication is never supplied without the approval of a doctor and the collaborating pharmacy. Results vary per person and depend on multiple factors, including lifestyle and individual health.

Do you want to know if a treatment might be suitable? Start the Medical intake at Wellumo, view how the trajectory works of neem Contact us with questions.