In many cases, what you’re advocating would be unrealistic. Some people would have to be malnourished in order to be thin. While you might not have a problem doing that to your dogs, I’m sure most people would not be willing to do that to themselves or their children.
You’re lucky if you are able to be thin without having to literally starve yourself or work out 2-3X what you do now. Others don’t have your luck.
I’ve known skinny people who live on fast food and rarely exercise. I’ve known heavy people who walk for miles every day and only eat organic foods with very little fat or sugar. Perhaps if you broadened your social circle to include people of all types, you would see that it’s not really all about “diet and exercise.”
