At the core of fitness is the principle of adaptability.
By putting my body through training (strength, cardio, athletic training, etc.), I am creating specific environment so my body can adapt and get stronger.
In order to adapt, my body has to be able to overcome the stress of training (recovery).
The body uses energy to recover, just as it uses energy to handle stress. Recovery suffers when all the energy is used towards handling stress. Over time the body will fight back, we lose motivation, we get fatigue, injured and reach the point of diminishing returns.
Don’t workout to exhaust yourself. Train so you can get better.
Our metabolism doesn’t slow down that much, we just become less active as we age.
The food industry isn’t trying to make us sick, they’ve been selling us exactly what we wanted.
It’s easy to play the blame game but ultimately the responsibility lies with us.
Check out the link below if you’re interested in a recent metabolism study on energy expenditure through human life.
https://www.science.org/doi/10.1126/science.abe5017