Harvard scientists used cutting-edge microscopic techniques to study 1,700 women and men, and found just one one common factor in every overweight person: low mitochondria levels. They also found one thing common in every person who was slim, toned and has smooth young skin: high mitochondria levels.

That’s because like little engines, mitochondria are tiny parts found inside every cell in our body that make energy from the food we eat and by burning fat stored in our body. This energy, called ATP, is what our body needs to do everything—from moving our muscles, to our heart beat, to thinking.

In short, mitochondria burn fat and fuel every part of our body to keep it running smoothly. So the more mitochondria you have, the more fat you burn!