This doesn't follow at all. Fat is an efficient way to put energy into long-term storage. This is a very useful feature for survival. It doesn't say anything about what is optimal as primary daily fuel. Most likely some fat is not harmful to metabolism, but excess may be, and how much is excess probably varies from person to person.If fat was harmful to our metabolism, it certainly wouldn't make sense to have it be our primary storage form of energy.
Are you sure it wasn't those bored aristocrats figuring that three meals a day was the minimum they could get away with allowing their employees/serfs and still have them put in a reasonable ROI (day's work)? While they themselves continued to eat elevenses and afternoon tea and supper in addition to those three 'meals' a day?People should likely be eating less often, not more. 3 meals a day is an invention of bored aristocrats. More than that an invention of supplement industry.
Depends which ones. There is hunger now (some of it self-inflicted), and there was hunger before. There have also been groups who have eaten generously in the past. At this point, life expectancy is low in the countries with low calorie intake, and high in the countries with high calorie intake (with a few exceptions, possibly more to do with who equitable the distribution of the available food is).Humans (industrialized) eat more and move less than ever.