How can I speed up my metabolism?

Do some people have a faster metabolism than others?

Body size, age, gender and genes all play a role in determining your metabolic rate.
Muscle cells require more energy to maintain than fat cells, so people with a higher muscle to fat ratio tend to have a higher BMR.
As we get older, we tend to gain fat and lose muscle. This explains why the BMR tends to decrease with age.
In general, men tend to have a faster metabolism as they have more muscle mass, heavier bones and less body fat than women, which is why their daily calorie allowance is higher.

Am I fat because of a slow metabolism?

People who struggle to lose weight often blame a slow metabolism. However, numerous studies involving thousands of people worldwide have failed to find evidence to support the widely held belief that overweight people must have slower metabolic rates.
In fact, the opposite appears true: overweight people may actually have a higher metabolism than their leaner counterparts,reflecting the energy requirements of maintaining a larger body size. When you account for differences in body size and composition, there is a remarkable similarity in energy expenditure between individuals.

Can losing weight too fast slow my metabolism?

Crash diets and other calorie-restricted diets can reduce your BMR. With some diets, your body is forced to break down muscle to use for energy. The lower your muscle mass, the slower your metabolism. With less muscle and a slower metabolism, it then becomes a lot easier to put body fat back on after coming off the diet.
Aerobic activity
Aerobic exercise is the most efficient way to burn calories. You should aim to do 150 minutes of aerobic activity, such as walking, cycling and swimming, a week. You can achieve this target by doing 30 minutes five days a week and breaking down your activity sessions in chunks of 10 minutes. To lose weight, you are likely to need to do more than 150 minutes a week and make changes to your diet. Physical activity guidelines for adults.