Staying in good shape also has major effects on your mentality, energy levels, and much more. It just turns out that as you age you've really gotta start shifting your diet hard from what it was like when you were younger.

However staying in shape by becoming a gym bro spending hours a week lifting weights and chugging protein powder also has major effects on your mentality, and those aren't good effects.

What effects do you think lifting weights regularly has on one's mentality, and why don't you think that those are not good effects?

Obesity isn't the thing you have just before you become a "gym bro". There's a chasm separating them.

Sure, and I maintain with healthy weight just on the normal walks around the village (although I did go slightly into the "overweight" category after one Christmas

The point is that it's very easy to go too far in the opposite direction, from being overweight to being a gym addict.