Body weight comes down to a simple score sheet. It compares energy in (food) with energy out (everything you burn). Tip the balance and see what happens.
Balanced
Energy balancein vs out
Energy out has three parts. BMR is about 60–70%. It is the energy you need just to stay alive. Physical activity is about 20–30%. The thermic effect of food is about 10%. It is the energy you use to digest food.
📷 Reference image
A real labeled figure to compare with the interactive above.
Energy Balance — OpenStax, CC BY 4.0 (via Wikimedia Commons)
