Have you ever experienced unexpected weight change (weight gain or weight loss), getting tired easily, or feeling sluggish? Well, all these, experts say, could be a result of slow or poor metabolism.

Scientifically, metabolism describes all the chemical processes that go on continuously inside one’s body to keep them alive and their organs functioning normally, such as breathing, repairing cells and digesting food.

These chemical processes, however, require energy, and the minimum amount of energy the body requires to carry out these chemical processes is called the basal metabolic rate (BMR).

According to Francis Kazungu, a general practitioner in Kigali, body size, age, gender, and genes play a big role when it comes to speeding or slowing down one’s metabolism.

Also, he says, one’s muscle cells can also determine metabolism rate, explaining that muscle cells require more energy to maintain than fat cells, therefore, people with more muscle than fat tend to have a faster metabolism.

When it comes to age, Kazungu says, as one gets older, they tend to gain fat and lose muscle, and this is the reason metabolism tends to slow down as one ages.

Another aspect when it comes to slow or fast metabolism, the medic points out, is that gender also plays a role, noting that in general, men tend to have a faster metabolism because they have more muscle mass, heavier bones, and less body fat than women.

Things that tend to slow down metabolism

Private Kamanzi, a nutritionist and dietician, says it’s vital to understand that metabolism is how your body changes food into energy.

For those with a slow metabolism, he says, depending on the reason, focusing on your habits can be helpful.

One of the things that tend to slow down metabolism, he says, is hormones. Here, he explains that a shift in hormones can put a halt on the body’s energy use, which can make one tired, thus leading to a slow metabolism rate.

Other factors include; some conditions, like an underactive or overactive thyroid and diabetes.

Moving forward, he mentions that stress too can affect metabolism by releasing hormones that trigger a slow-down.

Lack of sleep is also a factor, whereby studies have clearly shown that sleep deprivation can alter the glucose metabolism and hormones involved in regulating metabolism, that is, decreased leptin levels and increased ghrelin levels.

To rectify this, Kamanzi says for adults, one should at least have seven to nine hours of sleep on a daily basis.

If one has a deficiency in calcium, it can as also contribute to a slower metabolism.

It has been established that calcium is needed not just for the bones but also a quicker metabolism more than your bones as it is a key nutrient for a swift metabolism.

Calcium can be obtained from milk and dairy products, orange juice, and soy or almond milk.

Meanwhile, some drugs can also slow down your metabolism, these include many antidepressants and certain antipsychotics.

Speeding up your metabolism

Nelson Mukasa, a fitness trainer, says it has been established that engaging in physical activities, especially aerobic exercise, is the most effective way to burn calories.

This, he says, when aimed at doing at least 150 minutes activity such as walking, cycling, and swimming, can boost your metabolism rate.

He says one can simply achieve this target by doing 30 minutes one of these exercises at least five times a week.

Still on exercise, he says being active also improves your metabolism rate.

"It is essential to get involved in any physical activity of your choice, and make it a routine for better results. Walking or cycling can be helpful. In addition to this, taking in more protein at every meal has shown to increase your metabolism rate,” he says.

Kazungu says drink more water on a daily basis is essential too as it has been proven that people who drink water instead of sugary drinks are more successful at losing weight and keeping it off.

"This is because sugary drinks contain calories, so replacing them with water automatically reduces your calorie intake,” Kazungu says. 

Studies have shown that drinking 17 ounces (0.5 litres) of water increases resting metabolism by 10 to 30 per cent for about an hour.

Also, the medic says spicy food like peppers contain capsaicin, a substance that is said to boost metabolism.