Your TDEE is often referred to as your daily metabolism - although these two things are pretty different! Regardless, when someone speaks about increasing or decreasing their metabolism, they are typically referring to increasing or decreasing the number of calories their body burns and uses each day.
Unfortunately, there is no special pill, superfood, or supplement that can do this. Because your BMR and daily movement make up so much of your TDEE there are really only two ways to change your TDEE - change your weight or exercise more. In other words, gaining muscle and working out more often mean you get to eat more calories and maintain your weight!
Learn more about how your metabolism works and how you can get the most out of your daily burn.