To shed your weight, you have to spend energy. Let us analyze the energy thread bare.
If you have energy, we can do work. Hence energy=work.
What is work? Physics says: If a force acts on a body and it moves to a certain distance, the work is said to be done by the body.
Energy=work=force*distance.
What is the force? Newton second law says, force= mass*acceleration.
So, energy = mass*acceleration*distance
we know
Acceleration= velocity/time
Velocity = distance/time
putting everything in energy equation, we get,
energy= mass*distance^2 /time^2
So distance and time plays more important role in energy than mass
Mass: Small children requires less energy and less food to function. But a heavy adult requires lot of calories through food.
Distance and time: If you want to spend less energy, walk slowly. That is, take a long time to cover a small distance. If you intend to shed weight and calories, walk a long distance in short time. That is fast spaced walk.
Many physical quantities like force, density, frequency can be broken down to fundamental elements of mass , length and time which are the corner stones of physics. They mean matter, space and time without which nothing exist in this universe.